Comparison of the diagnostic yield of aCGH and genome-wide sequencing across different neurodevelopmental disorders.

Most consensus recommendations for the genetic diagnosis of neurodevelopmental disorders (NDDs) do not include the use of next generation sequencing (NGS) and are still based on chromosomal microarrays, such as comparative genomic hybridization array (aCGH). This study compares the diagnostic yield obtained by aCGH and clinical exome sequencing in NDD globally and its spectrum of disorders. To that end, 1412 patients clinically diagnosed with NDDs and studied with aCGH were classified into phenotype categories: global developmental delay/intellectual disability (GDD/ID); autism spectrum disorder (ASD); and other NDDs. These categories were further subclassified based on the most frequent accompanying signs and symptoms into isolated forms, forms with epilepsy; forms with micro/macrocephaly and syndromic forms. Two hundred and forty-five patients of the 1412 were subjected to clinical exome sequencing. Diagnostic yield of aCGH and clinical exome sequencing, expressed as the number of solved cases, was compared for each phenotype category and subcategory. Clinical exome sequencing was superior than aCGH for all cases except for isolated ASD, with no additional cases solved by NGS. Globally, clinical exome sequencing solved 20% of cases (versus 5.7% by aCGH) and the diagnostic yield was highest for all forms of GDD/ID and lowest for Other NDDs (7.1% versus 1.4% by aCGH) and ASD (6.1% versus 3% by aCGH). In the majority of cases, diagnostic yield was higher in the phenotype subcategories than in the mother category. These results suggest that NGS could be used as a first-tier test in the diagnostic algorithm of all NDDs followed by aCGH when necessary.

Genetic landscape of 6089 inherited retinal dystrophies affected cases in Spain and their therapeutic and extended epidemiological implications.

Inherited retinal diseases (IRDs), defined by dysfunction or progressive loss of photoreceptors, are disorders characterized by elevated heterogeneity, both at the clinical and genetic levels. Our main goal was to address the genetic landscape of IRD in the largest cohort of Spanish patients reported to date. A retrospective hospital-based cross-sectional study was carried out on 6089 IRD affected individuals (from 4403 unrelated families), referred for genetic testing from all the Spanish autonomous communities. Clinical, demographic and familiar data were collected from each patient, including family pedigree, age of appearance of visual symptoms, presence of any systemic findings and geographical origin. Genetic studies were performed to the 3951 families with available DNA using different molecular techniques. Overall, 53.2% (2100/3951) of the studied families were genetically characterized, and 1549 different likely causative variants in 142 genes were identified. The most common phenotype encountered is retinitis pigmentosa (RP) (55.6% of families, 2447/4403). The most recurrently mutated genes were PRPH2, ABCA4 and RS1 in autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) NON-RP cases, respectively; RHO, USH2A and RPGR in AD, AR and XL for non-syndromic RP; and USH2A and MYO7A in syndromic IRD. Pathogenic variants c.3386G > T (p.Arg1129Leu) in ABCA4 and c.2276G > T (p.Cys759Phe) in USH2A were the most frequent variants identified. Our study provides the general landscape for IRD in Spain, reporting the largest cohort ever presented. Our results have important implications for genetic diagnosis, counselling and new therapeutic strategies to both the Spanish population and other related populations.

Genotype-Phenotype Correlations in a Spanish Cohort of 506 Families With Biallelic ABCA4 Pathogenic Variants.

PURPOSE: To define genotype-phenotype correlations in the largest cohort study worldwide of patients with biallelic ABCA4 variants, including 434 patients with Stargardt disease (STGD1) and 72 with cone-rod dystrophy (CRD). DESIGN: Cohort study. METHODS: We characterized 506 patients with ABCA4 variants using conventional genetic tools and next-generation sequencing technologies. Medical history and ophthalmologic data were obtained from 372 patients. Genotype-phenotype correlation studies were carried out for the following variables: variant type, age at symptom onset (AO), and clinical phenotype. RESULTS: A total of 228 different pathogenic variants were identified in 506 ABCA4 patients, 50 of which were novel. Genotype-phenotype correlations showed that most of the patients with biallelic truncating variants presented with CRD and that these cases had a significantly earlier AO than patients with STGD1. Three missense variants are associated with CRD for the first time (c.1804C>T; p.[Arg602Trp], c.3056C>T; p.[Thr1019Met], and c.6320G>C; p.[Arg2107Pro]). Analysis of the most prevalent ABCA4 variant in Spain, c.3386G>T; p.(Arg1129Leu), revealed that is correlated to STGD1, later AO, and foveal sparing. CONCLUSIONS: Our study, conducted in the largest ABCA4-associated disease cohort reported to date, updates the genotype-phenotype model established for ABCA4 variants and broadens the mutational spectrum of the gene. According to our observations, patients with ABCA4 presenting with 2 truncating variants may first present features of STGD1 but eventually develop rod dysfunction, and specific missense variants may be associated with a different phenotype, underscoring the importance of an accurate genetic diagnosis. Also, it is a prerequisite for enrollment in clinical trials, and to date, no other treatment has been approved for STGD1.

Genomic Landscape of Sporadic Retinitis Pigmentosa: Findings from 877 Spanish Cases.

PURPOSE: We aimed to unravel the molecular basis of sporadic retinitis pigmentosa (sRP) in the largest cohort reported to date. DESIGN: Case series. PARTICIPANTS: A cohort of 877 unrelated Spanish sporadic cases with a clinical diagnosis of retinitis pigmentosa (RP) and negative family history. METHODS: The cohort was studied by classic genotyping or targeted next-generation sequencing (NGS). Multiplex ligation-dependent probe amplification (MLPA) and array-based comparative genomic hybridization were performed to confirm copy number variations detected by NGS. Quantitative fluorescent polymerase chain reaction was assessed in sRP cases carrying de novo variants to confirm paternity. MAIN OUTCOME MEASURES: The study of the sRP cohort showed a high proportion of causal autosomal dominant (AD) and X-linked (XL) variants, most of them being de novo. RESULTS: Causative variants were identified in 38% of the patients studied, segregating recessively in 84.5% of the solved cases. Biallelic variants detected in only 6 different autosomal recessive genes explained 50% of the cases characterized. Causal AD and XL variants were found in 7.6% and 7.9% of cases, respectively. Remarkably, 20 de novo variants were confirmed after trio analysis, explaining 6% of the cases. In addition, 17% of the solved sRP cases were reclassified to a different retinopathy phenotype. CONCLUSIONS: This study highlights the clinical utility of NGS testing for sRP cases, expands the mutational spectrum, and provides accurate prevalence of mutated genes. Our findings evidence the underestimated role of de novo variants in the etiology of RP, emphasizing the importance of segregation analysis as well as comprehensive screening of genes carrying XL and AD variants in sporadic cases. Such in-depth study is essential for accurate family counseling and future enrollment in gene therapy-based treatments.

Epidemiological and clinical analysis of a consecutive series of conjoined twins in Spain.

PURPOSE: The aim of the study was to analyze the frequency and certain epidemiological characteristics of a consecutive series of conjoined twins born in Spain. MATERIAL AND METHODS: We used data from the Spanish Collaborative Study of Congenital Malformations for the period April 1976 to 2006. Because the Spanish law permitting voluntary termination of pregnancies (TOP) when the fetus presented malformations was effective by the end of 1985, we analyzed the data in 4 periods, 2 before 1986 and 2 after. During the first period (1976-1979) only live births were recorded, whereas both still and live births were included in the other three (1980-1985, 1986-1995, and 1996-2006). In the present study, the cases were classified as symmetrical (16 pairs) and asymmetrical (1 pair) conjoined twins. Each pair of conjoined twins was considered as only one case for calculations, regardless of the type of union. RESULTS: Among a total of 2,281,604 consecutive births between 1980 and 2006, there were a total of 15 cases of symmetrical conjoined twins giving a frequency of 0.70 per 100,000 (1/152,107), whereas there was only 1 stillborn asymmetrical conjoined twin pair (0.04/100,000). Among the 13,418 consecutive stillborns surveyed, 6 cases of conjoined twins were identified (either symmetrical or asymmetrical) giving a frequency of 44.72 per 100,000, and 11 pairs were identified among the 2,425,583 total live births surveyed during the first period 1976 to 1979, a frequency of 0.45 per 100,000. Thus, the frequency among stillborn infants is 99.34 times higher than that observed among live births. However, the frequency for the total births (3 last periods) showed a decreasing trend from 1.47 per 100,000 birth in the first period (1980-1985) when TOP was illegal, to a value of 0.09 per 100,000 in the last period, more than 16-fold lower, probably because of the TOP of affected fetuses. Therefore, we consider that the frequencies observed in the period 1980 to 1985 are the basal values in our population. The most frequent type observed was thoracopagus, with an overall prevalence at birth of 0.44 per 100,000 (1/228,160) from 1980 to 2006, representing 58.82% of the total population of symmetric conjoined twin pairs. Diprosopus pairs were the next most common group (11.76%). Most of the cases were females (4 males/11 females), and although this appeared to be mainly because of the thoracopagus pairs (males-females, 2:8), in such a small number of cases, it is not possible to determine the ratios for the other groups. Gestational age was significantly shorter than in control twins for each type studied. CONCLUSIONS: We conclude that it is incorrect to consider that all types of conjoined twins have the same epidemiological characteristics, such as the frequency at birth. The differences observed may be related with the distinct embryo-fetal mortality of each type of conjoined twins in different populations, and the sex ratio, among others.

[Analysis of the frequencies of genotype combinations of 4 polymorphisms of genes acting on the folate cycle in the Spanish population]. / Análisis de las frecuencias de todas las combinaciones genotípicas de 4 polimorfismos de genes implicados en el ciclo del folato en la población española.

BACKGROUND AND OBJECTIVE: Studies on different populations have shown a great variability of the frequencies of different polymorphisms in genes acting in the folate cycle. The present study was aimed to analyze the frequency in the Spanish population of each genotype combination of four polymorphisms, one of them -1561C-T of the glutamate carboxypeptidase II (GCPII) gene- being the first time that is studied in Spain. The study included a meta-analysis of the published data. SUBJECTS AND METHOD: Using the Spanish Collaborative Study of Congenital Malformations (ECEMC) Network, blood samples of 190 mother-child couples with newborns without any congenital defect, were obtained from 15 Spanish autonomous regions. The study polymorphisms were the 677C-T and 1298A-C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR), the 66A-G of the methionine synthase reductase (MTRR), and the 1561C-T polymorphism of the GCPII gene. To estimate the range for the population frequencies, 99% confidence intervals were calculated. RESULTS: The frequencies observed in our country were significantly different from others, being similar to those obtained in countries of the Mediterranean European area. The 1561C-T polymorphism of the GCPII gene has a frequency in Spain of 5.11%, which is also similar to the values observed in France (5%) and in Italy (6%). On the other hand, the frequency of the genotypes CTCC, TTAC is quite few, while the genotype TTCC was not observed in any mother or infants. A meta-analysis was performed for a big sample (23,612 individuals) and the results showed that with a 99% of probability the values for the genotype combinations CTCC, TTAC, and TTCC were within 0.10-0.24; 0.20-0.36; and 0.003-0.05, respectively. CONCLUSIONS: Our results are important to further analyze the relationship with some health problems and individual susceptibilities. Indeed, considering the published observations of the structure and function of the MTHFR enzyme, it is understandable that those genotype combinations that are quite little frequent, may be related to the embryo-fetal viability, and to the life style of each population.

The safety of calcium channel blockers during pregnancy: a prospective, multicenter, observational study.

OBJECTIVE: To assess the safety of calcium channel blockers during the first trimester of pregnancy. STUDY DESIGN: A multicenter (n=11), prospective observational study of the European Network of Teratology Information Services (ENTIS). The rate of major birth defects was compared between a cohort of pregnant women exposed to calcium channel blockers during the first trimester (n=299) and a control group not exposed to potential teratogens (n=806). RESULTS: Major birth defects were not more common in the study group than in the control group. Birth weight was significantly lower in exposed term newborns. There were more preterm infants in the study group than in the control group (23.8% vs. 6.5%). These adverse effects are more likely due to the underlying disease than to the medication. CONCLUSION: This study suggests that calcium channel blockers during the first trimester of pregnancy do not represent a major teratogenic risk.

Análisis de las frecuencias de todas las combinaciones genotípicas de 4 polimorfismos de genes implicados en el ciclo del folato en la población española / Analysis of the frequencies of genotype combinations of 4 polymorphisms of genes acting on the folate cycle in the Spanish population

Fundamento y objetivo: Distintas poblaciones muestran diferencias en cuanto a las frecuencias de polimorfismos de genes del ciclo del folato. El objetivo de este estudio ha sido analizar las frecuencias genotípicas de 4 polimorfismos, uno de los cuales -1561C-T del gen de la glutamato carboxipeptidasa II (GCPII)- se analiza por primera vez en España, así como realizar un metaanálisis de los datos publicados. Sujetos y método: Utilizando la Red del Estudio Colaborativo Español de Malformaciones Congénitas (ECEMC) se obtuvieron, en 15 comunidades autónomas, muestras de sangre de 190 parejas madres-recién nacidos sin defectos. Se analizaron los polimorfismos 677C-T y 1298A-C del gen de la metilentetrahidrofolato reductasa (MTHFR); 66A-G del gen de la metionina sintasa reductasa (MTRR), y 1561C-T del gen de la GCPII. Los valores poblaciones se calcularon por los intervalos de confianza del 99%. Resultados: Las frecuencias en nuestro país difieren de las de otras poblaciones, excepto las del área mediterránea europea. La frecuencia del polimorfismo 1561C-T (gen GCPII) en España es del 5,11%, igual que en Francia (5%) e Italia (6%). Las de MTHFR, CTCC y TTAC en España son muy bajas y no se observó ninguna madrehijo con TTCC. El metaanálisis (23.612 individuos) mostró que, con un 99% de probabilidad, las frecuencias poblacionales de CTCC, TTAC y TTCC serían de 0,10-0,24; 0,20-0,36, y 0,003-0,05, respectivamente. Conclusiones: Estos resultados son importantes para estudios sobre la relación de dichos polimorfismos con problemas de salud y susceptibilidad individuales, así como para investigar sus implicaciones biológicas. Tras los últimos hallazgos estructurales y funcionales en la MTHFR pueden entenderse las diferencias, porque los genotipos infrecuentes podrían relacionarse con la viabilidad fetal, las concentraciones de homocisteína materno/ fetal y los estilos de vida

Background and objective: Studies on different populations have shown a great variability of the frequencies of different polymorphisms in genes acting in the folate cycle. The present study was aimed to analyze the frequency in the Spanish population of each genotype combination of four polymorphisms, one of them -1561CT of the glutamate carboxypeptidase II (GCPII) gene- being the first time that is studied in Spain. The study included a meta-analysis of the published data. Subjects and method: Using the Spanish Collaborative Study of Congenital Malformations (ECEMC) Network, blood samples of 190 mother-child couples with newborns without any congenital defect, were obtained from 15 Spanish autonomous regions. The study polymorphisms were the 677C-T and 1298A-C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR), the 66A-G of the methionine synthase reductase (MTRR), and the 1561C-T polymorphism of the GCPII gene. To estimate the range for the population frequencies, 99% confidence intervals were calculated. Results: The frequencies observed in our country were significantly different from others, being similar to those obtained in countries of the Mediterranean European area. The 1561C-T polymorphism of the GCPII gene has a frequency in Spain of 5.11%, which is also similar to the values observed in France (5%) and in Italy (6%). On the other hand, the frequency of the genotypes CTCC, TTAC is quite few, while the genotype TTCC was not observed in any mother or infants. A meta-analysis was performed for a big sample (23,612 individuals) and the results showed that with a 99% of probability the values for the genotype combinations CTCC, TTAC, and TTCC were within 0.10-0.24; 0.20-0.36; and 0.003-0.05, respectively. Conclusions: Our results are important to further analyze the relationship with some health problems and individual susceptibilities. Indeed, considering the published observations of the structure and function of the MTHFR enzyme, it is understandable that those genotype combinations that are quite little frequent, may be related to the embryo-fetal viability, and to the life style of each population

Risk of hypospadias in newborn infants exposed to valproic acid during the first trimester of pregnancy: a case-control study in Spain.

BACKGROUND: Hypospadias is one of the most frequently occurring genital anomalies described in infants prenatally exposed to valproic acid (VA). However, to our knowledge, only one publication has studied a potential causal relationship between VA and hypospadias, only estimating the unadjusted global risk. Here we present the results of a multivariate case-control study aimed at analysing and quantifying the specific risk of hypospadias in newborn infants exposed to VA during the first trimester of pregnancy. METHODS: The data analysed here were derived from the Spanish Collaborative Study of Congenital Malformations (ECEMC), an ongoing, hospital-based, case-control study and surveillance system in which collaborating paediatricians identify case and control infants. The paediatricians collect the same data for both case and control infants, blinded to information on any prenatal exposure. The information includes 312 items related to many prenatal exposures, including drug exposure, reproductive and family history, and other characteristics. The sample analysed included 2,393 infants with hypospadias and 12,465 male controls. RESULTS: The results showed that the unadjusted risk of hypospadias in infants prenatally exposed to VA was 5.23 (95% CI 2.31, 11.86; p < 0.00001). Once adjusted for 13 potential confounding factors using conditional logistic regression analyses, the value of the risk was of a similar magnitude (odds ratio = 5.71; 95% CI 1.78, 18.36; p = 0.003). In addition, the frequency of hypospadias in the study population was approximately 1.8/1000 births. This allowed us to calculate the specific risk for an infant with hypospadias to be born to an exposed mother, which was 1 child in 97 births to mothers using VA during the first trimester of pregnancy. We consider this information much more useful for risk assessment than the risk value itself. CONCLUSIONS: An alteration of placental gonadotrophic stimulation caused by changes in gonadotropin-releasing hormone release produced by the effects of VA on GABA is a possible pathogenic mechanism. Our results support the relationship between prenatal exposure to VA and hypospadias.

Does single umbilical artery (SUA) predict any type of congenital defect? Clinical-epidemiological analysis of a large consecutive series of malformed infants.

Most studies associating different types of malformations with the presence of a single umbilical artery (SUA) are based on small and selected series. Here, we present the results of a study aimed at identifying the most frequent, and the most specific anomalies related to SUA. We analyzed 19,909 consecutive newborn infants with congenital malformations, from the Spanish Collaborative Study of Congenital Malformations (ECEMC). To estimate the specificity of the relationship of different congenital defects with SUA, we calculated their relative frequencies (RF) by dividing their frequency in infants with SUA by the corresponding frequency in newborn infants without SUA. Using the different levels of the ECEMC coding system, we calculated the RFs in three steps: (a) a group of individual congenital defects, (b) different groups of malformed infants, and (c) each individual malformation by its clinical presentation in some of the studied groups of malformed infants. The defects most specifically associated with SUA were bilateral renal agenesis and imperforate anus, followed by unilateral renal agenesis, and vertebral defects, the RF of which indicated that they were between 7.99 and 9.93 times more frequent among malformed infants with SUA than among malformed infants without SUA. However, these defects were not as frequent in the group of infants with SUA, as cardiovascular anomalies. Regarding the association of SUA in the groups of malformed infants, the most specific groups were body stalk defects and sirenomelia. Finally, we analyzed the association of the individual defects by different groups of malformed infants in order to identify if the individual defects are associated with SUA in any type of clinical presentation, and in relation to some groups of infants with genetic disorders. The results, together with the embryonic development of the umbilical cord, strongly suggest that not all cases of SUA have the same cause, and that all previously suggested mechanisms may be possible but with different frequencies.

[Adverse effects of selective serotonin reuptake inhibitors use during the third trimester of pregnancy and prevention guidelines]. / Efectos adversos de los inhibidores selectivos de la recaptación de serotonina durante el tercer trimestre de la gestación y guías de prevención.

Selective Serotonin Reuptake Inhibitors (SSRIs) have become the drug of choice for the treatment of depression and have shown to be effective in the treatment for other mental disorders. Recently, several articles have reported about the adverse effects observed in newborns after maternal exposure to these drugs during the last trimester of pregnancy. In this work, a review of literature is presented, regarding the above mentioned adverse effects. Moreover, some guidelines for the rational use of these drugs during the last trimester of pregnancy and for the management of prenatally exposed newborns are provided.

Efectos adversos de los inhibidores selectivos de la recaptación de serotonina durante el tercer trimestre de la gestación y guías de prevención / Side effects of selective serotonin reuptake inhibitors use during the third trimester of pregnancy and guidelines

Los inhibidores selectivos de la recaptación de serotonina (ISRS) se han convertido en el tratamiento de elección de la depresión y han demostrado ser efectivos en el tratamiento de otros trastornos mentales diversos. Últimamente, se han publicado numerosos artículos sobre los efectos adversos observados en el recién nacido tras la utilización materna de estos fármacos durante el último trimestre de la gestación. En este trabajo se realiza una revisión de la bibliografía de dichos efectos adversos y se enumeran unas pautas de actuación para el uso racional de estos fármacos durante la última parte de la gestación, así como para el manejo de los recién nacidos expuestos prenatalmente

Selective Serotonin Reuptake Inhibitors (SSRIs) have become the drug of choice for the treatment of depression and have shown to be effective in the treatment for other mental disorders. Recently, several articles have reported about the adverse effects observed in newborns after maternal exposure to these drugs during the last trimester of pregnancy. In this work, a review of literature is presented, regarding the above mentioned adverse effects. Moreover, some guidelines for the rational use of these drugs during the last trimester of pregnancy and for the management of prenatally exposed newborns are provided

Evolución secular y por comunidades autónomas de la frecuencia de síndrome de Down al nacimiento en hijos de madres jóvenes / Trends in the frequency of Down syndrome in the infants of young mothers in the autonomous communities of Spain

Introducción: Hay una relación universalmente probada entre la edad materna y el riesgo para tener hijos con síndrome de Down (SD), que es mayor a medida que aquélla aumenta. El grupo de madres con más de 34 años (entre un 9 y un 14% del total) tiene globalmente 10 veces más riesgo que el grupo con menos de 35 años. Por ello, las madres con 35 años o más han sido la población diana para el diagnóstico prenatal del SD. Como consecuencia de ello, la frecuencia de recién nacidos con SD en este grupo de madres va disminuyendo con el tiempo. Sin embargo, el desarrollo de nuevas técnicas de cribado ha facilitado también la detección de grupos de riesgo para SD en las madres con menos de 35 años. El objetivo de este trabajo era estudiar la evolución de la frecuencia de SD en los recién nacidos de madres menores de 35 años en España, durante 28 años y por comunidades autónomas. Material y métodos: Se han utilizado los datos registrados por el Estudio Colaborativo Español de Malformaciones Congénitas (ECEMC) entre 1976 y 2003, procedentes de todas las comunidades autónomas. El ECEMC es un programa de investigación clínico-epidemiológica sobre las causas de los defectos congénitos, estructurado como un sistema permanente de registro con un diseño de tipo casos y controles y de base hospitalaria. Para el análisis de la tendencia temporal se ha utilizado el test de tendencia lineal (χ² con un grado de libertad) y la χ² con k-2 grados de libertad para detectar desviaciones de la linealidad. Resultados: La frecuencia global de SD en el grupo de madres menores de 35 años ha disminuido de forma estadísticamente significativa con el tiempo (p = 0,03), fundamentalmente los últimos años. Dicho descenso es estadísticamente significativo en Cataluña (p = 0,002) y Galicia (p = 0,01). Sin embargo, no se alcanza la significación estadística para los descensos observados en Andalucía, Islas Baleares, Madrid y País Vasco. En la Comunidad Foral de Navarra y en La Rioja no se ha podido evaluar la tendencia más reciente porque estas comunidades interrumpieron temporalmente su participación en el estudio. En el Principado de Asturias hemos detectado un incremento secular significativo, y en el resto de las comunidades no se aprecian tendencias destacables. Además, el porcentaje de madres con más de 34 años ha aumentado progresivamente hasta alcanzar el 20,54% del total de madres en 2003, mientras que el número y el porcentaje de niños con SD que nacieron de madres con más de 34 años ha ido disminuyendo hasta ser inferior al de niños con SD hijos de madres con menos de 35 años. Discusión: La evolución global con el transcurso del tiempo de la frecuencia de SD en hijos de madres con menos de 35 años muestra ya un descenso significativo, pero éste no es igual en todas las comunidades autónomas. Este hecho puede ser consecuencia de la aplicación de planes diversos, que se deberían homogeneizar, dirigidos a la detección prenatal del SD en el grupo de madres de menor riesgo

Introduction: There is a universally proven relationship between maternal age and the risk of having an infant with Down syndrome (DS); the risk is greater as maternal age increases. The overall risk is increased almost 10-fold in mothers aged more than 34 years (traditionally accounting for 9-14% of all mothers) than in those aged less than 35 years. For this reason, mothers aged 35 years or older have constituted the target population for prenatal diagnosis of DS and, consequently, the frequency of newborn infants with DS in this age group has clearly decreased over time. However, the development of new prenatal screening techniques has allowed groups with a higher risk to be detected among young mothers. The aim of this study was to analyze trends in the frequency of DS in the infants of mothers aged less than 35 years old in Spain over the last 28 years by autonomous communities in Spain. Material and methods: Data from the Spanish Collaborative Study of Congenital Malformations (Estudio Colaborativo Español de Malformaciones Congénitas [ECEMC]) corresponding to the period 1976-2003, and obtained from all the autonomous communities in Spain, were used. The ECEMC is a clinical-epidemiological research program on the causes of congenital defects, structured as a permanent registration system with a case-control design. The program is hospital-based. For the analysis of time trends, the lineal trend test (χ² with 1 degree of freedom) was used. To detect deviations from linearity, a χ² test with k-2 degrees of freedom was used. Results: The overall frequency of DS in mothers younger than 35 years significantly decreased over time (p = 0.03), mainly in the last few years. This decrease was statistically significant in the autonomous communities of Catalonia (p = 0.002) and Galicia (p = 0.01), but was nonsignificant in Andalusia, Balearic Island, Madrid and the Basque Country. In Navarre and La Rioja, the most recent tendency could not be evaluated because these regions temporarily interrupted their participation in the study. A statistically significant increase was found in the Principality of Asturias. No notable tendencies were found in the remaining regions. The percentage of mothers older than 34 years progressively increased, accounting for 20.54% of all mothers in 2003, while the number and percentage of infants with DS born to mothers older than 34 decreased and was lower those of infants with DS born to mothers younger than 35 years. Discussion: Although the time trend of the frequency of DS in the infants of mothers aged less than 35 years showed a significant overall decrease, differences were found in the distinct autonomous communities. This finding could be a result of the application of different programs for the prenatal detection of DS in lower-risk maternal age groups. Therefore, homogenizing these programs would seem advisable

[Antenatal exposure to corticosteroids for fetal lung maturation and its repercussion on weight, length and head circumference in the newborn infant]. / Exposición prenatal a glucocorticoides para acelerar la maduración pulmonar fetal y su repercusión sobre el peso, la talla y el perímetro cefálico del recién nacido.

BACKGROUND AND OBJECTIVE: To study the effects of antenatal corticosteroids treatment to promote fetal lung maturation, on fetal growth, depending on the number of the courses administered. PATIENTS AND METHOD: The study was based on data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), analysing a sample of 29,557 singleton liveborn infants without congenital defects. An stratified analysis by gestational age was performed to compare the weight, length and head circumference at birth, in the exposed and unexposed infants to dexamethasone/betamethasone. To control confounding factors (year of birth, maternal age, gestational age, parity, maternal smoking and/or alcohol consumption, gestational diabetes, non-gestational diabetes and other maternal chronic diseases) we used a general linear model with random effects, being the randomised variable the place of birth. RESULTS: The exposure to more than one course of antenatal corticosteroids resulted in a significant reduction of birth weight, length and head circumference in singleton preterm infants. The birth weight decreased by 22% (p < 0.0001), the length 5% (p = 0.002) and the head circumference 6% (p = 0.0005). The treatment with only one course reduced also significantly the weight and length but not the head circumference. In addition, we observed a significant interaction between the treatment and gestational age at birth indicating that the effect of corticosteroids is stronger in the most premature babies. CONCLUSIONS: In this retrospective analysis, the antenatal exposure to corticosteroids to promote fetal maturation is associated with diminished weight, length and head circumference in the premature newborn infant. This negative effect was greater in those premature babies exposed to multiple courses.

Exposición prenatal a glucocorticoides para acelerar la maduración pulmonar fetal y su repercusión sobre el peso, la talla y el perímetro cefálico del recién nacido / Antenatal exposure to corticosteroids for fetal lung maturation and its repercussion on weight, length and head circumference in the newborn infant

Fundamento y objetivo: Analizar el impacto sobre el crecimiento fetal del tratamiento con glucocorticoides para acelerar la maduración del pulmón fetal, según el número de ciclos administrados. Pacientes y método: Se ha utilizado la base de datos del Estudio Colaborativo Español de Malformaciones Congénitas (ECEMC) en una muestra de 29.557 recién nacidos vivos no gemelos sin defectos congénitos. Se compararon, mediante un análisis estratificado por edad gestacional al nacimiento, el peso, la talla y el perímetro cefálico de los expuestos prenatalmente a betametasona o dexametasona con los no expuestos. Para el control de factores de confusión o interacción (año de nacimiento, edad materna, edad gestacional, paridad, consumo de tabaco y/o bebidas alcohólicas, diabetes crónica, diabetes gestacional y otras enfermedades crónicas) se utilizó un modelo lineal general con efectos aleatorios, en el que la variable aleatoria fue el lugar de nacimiento. Resultados: La exposición prenatal a 2 o más ciclos de glucocorticoides comporta una disminución del peso, la talla y el perímetro cefálico en prematuros. Concretamente, en la muestra analizada supone una pérdida del 22% del peso (p < 0,0001), del 5% de la talla (p = 0,002) y del 6% del perímetro cefálico al nacimiento (p = 0,0005). La exposición a un solo ciclo también comporta una pérdida significativa del peso y la talla, aunque no del perímetro cefálico. Asimismo, se ha observado una interacción significativa entre el tratamiento y la edad gestacional, lo cual indica que el impacto de la medicación es más acusado en los más prematuros. Conclusiones: En este análisis retrospectivo la exposición prenatal a glucocorticoides para acelerar la maduración pulmonar fetal se asoció, en los recién nacidos prematuros, a un efecto negativo sobre el peso, la talla y el perímetro cefálico. Este efecto fue más acusado en los prematuros expuestos a más de un ciclo de glucocorticoides

Background and objective: To study the effects of antenatal corticosteroids treatment to promote fetal lung maturation, on fetal growth, depending on the number of the courses administered. Patients and method: The study was based on data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), analysing a sample of 29,557 singleton liveborn infants without congenital defects. An stratified analysis by gestational age was performed to compare the weight, length and head circumference at birth, in the exposed and unexposed infants to dexamethasone/betamethasone. To control confounding factors (year of birth, maternal age, gestational age, parity, maternal smoking and/or alcohol consumption, gestational diabetes, non-gestational diabetes and other maternal chronic diseases) we used a general linear model with random effects, being the randomised variable the place of birth. Results: The exposure to more than one course of antenatal corticosteroids resulted in a significant reduction of birth weight, length and head circumference in singleton preterm infants. The birth weight decreased by 22% (p < 0.0001), the length 5% (p = 0.002) and the head circumference 6% (p = 0.0005). The treatment with only one course reduced also significantly the weight and length but not the head circumference. In addition, we observed a significant interaction between the treatment and gestational age at birth indicating that the effect of corticosteroids is stronger in the most premature babies. Conclusions: In this retrospective analysis, the antenatal exposure to corticosteroids to promote fetal maturation is associated with diminished weight, length and head circumference in the premature newborn infant. This negative effect was greater in those premature babies exposed to multiple courses

Vitamin K antagonists and pregnancy outcome. A multi-centre prospective study.

Vitamin K antagonists (VKA) are known to act as teratogens; however, there is still uncertainty about the relative risk for birth defects and the most sensitive period. In a multi-centre (n = 12), observational, prospective study we compared 666 pregnant women exposed to phenprocoumon (n = 280), acenocoumarol (n = 226), fluindione (n = 99), warfarin (n = 63) and phenindione (n = 2) to a non-exposed control group (n = 1,094). Data were collected by institutes collaborating in the European Network of Teratology Information Services (ENTIS) during individual risk counselling between 1988 and 2004. Main outcome measures were coumarin embryopathy and other birth defects, miscarriage rate, birth-weight, and prematurity. The rate of major birth defects after 1st trimester exposure was significantly increased (OR 3.86, 95% CI 1.86-8.00). However, there were only two coumarin embryopathies (0.6%; both phenprocoumon). Prematurity was more frequent (16.0% vs. 7.6%, OR 2.61, 95% CI 1.76-3.86), mean gestational age at delivery (37.9 vs.39.4, p<0.001), and mean birth weight of term infants (3,166 g vs. 3,411 g; p < 0.001) were lower compared to the controls. Using the methodology of survival analysis, miscarriage rate reached 42% vs. 14% (hazard ratio 3.36; 95% CI 2.28-4.93). In conclusion, use of VKA during pregnancy increases the risk of structural defects and other adverse pregnancy outcomes. The risk for coumarin embryopathy is, however, very small, in particular when therapy during the 1(st) trimester did not take place later than week 8 after the 1(st) day of the last menstrual period. Therefore, elective termination of a wanted pregnancy is not recommended if (inadvertent) exposure took place in early pregnancy. Close follow-up by the obstetrician including level II ultrasound should be recommended in any case of VKA exposure during pregnancy.

Análisis comparativo de las frecuencias de ciertos defectos congénitos y su evolución secular en 11 comunidades autónomas / Comparative analysis of the frequencies of diverse congenital birth defects and their time trends in 11 autonomous communities in Spain

Fundamento y objetivo: El conocimiento de la frecuencia de los distintos defectos congénitos a lo largo del tiempo y en las diferentes comunidades autónomas es importante, no sólo para cuantificar la magnitud del problema y planificar los recursos necesarios, sino para disponer de sistemas de vigilancia y analizar el impacto de las diversas actuaciones sanitarias. El objetivo de este trabajo ha sido analizar comparativamente en las 11 comunidades autónomas que participan en la REpIER (Red Epidemiológica de Investigación en Enfermedades Raras) las frecuencias de 6 tipos de defectos congénitos. Sujetos y métodos: Se han utilizado los datos del ECEMC (Estudio Colaborativo Español de Malformaciones Congénitas) correspondientes a las 11 autonomías que participan en la REpIER (Andalucía, Aragón, Canarias, Cantabria, Castilla-La Mancha, Cataluña, Comunidad de Madrid, Comunidad Valenciana, Extremadura, La Rioja y el Principado de Asturias), en el período 1980-2003. El ECEMC es un programa de investigación clínico-epidemiológico acerca de las causas de los defectos congénitos, estructurado como un sistema permanente de registro, con un diseño de tipo caso-control y de base hospitalaria. Los defectos estudiados han sido: anencefalia; espina bífida; labio leporino, con o sin fisura del paladar; sólo fisura del paladar; defectos por reducción de extremidades, y síndrome de Down en hijos de mujeres con más de 34 años. Para el análisis de la tendencia temporal en cada autonomía se ha utilizado la prueba de tendencia lineal (χ2con 1 grado de libertad) y la χ2 con k-2 grados de libertad para detectar desviaciones de la linealidad. Resultados: La distribución temporal de las frecuencias no es igual para todos los defectos estudiados ni en todas las comunidades. La mayor concordancia entre las 11 autonomías estudiadas se observa para la disminución secular del síndrome de Down en madres de más de 34 años, que es significativa en 8 comunidades. La anencefalia disminuye significativamente en 6 autonomías, y en otras 2 no se registró ningún caso. La espina bífida muestra descensos estadísticamente significativos en 6 circunscripciones autonómicas. La distribución secular de las frecuencias de los otros 3 tipos de malformaciones estudiadas no presenta tendencias significativas en la mayoría de las autonomías. Conclusiones: Desde que hay en España la posibilidad legal de realizar una interrupción voluntaria del embarazo tras la detección prenatal de anomalías, se observa un claro descenso de las frecuencias al nacimiento de los defectos para los que es posible el diagnóstico prenatal. Dicho descenso no ha sido igual en todas las comunidades, ni en lo que se refiere a su comienzo ni en cuanto a su intensidad, lo que puede estar poniendo de manifiesto, entre otros factores, diferencias en cuanto a la atención sanitaria

Background and objective: Knowledge of the frequency of the distinct congenital defects over time in the various Autonomous Communities in Spain is important, not only to quantify the scope of the problem and to plan the necessary resources, but also to have surveillance systems and analyze the impact of the diverse health interventions. The aim of this study was to analyze the comparative frequencies of 6 types of congenital defect in the 11 Autonomous Communities participating in the Epidemiological Network on Rare Disease Research (REpIER). Subjects and methods: We analyzed data from the Spanish Collaborative Study of Congenital Malformations (ECEMC) corresponding to the 11 Autonomous Communities participating in REpIER (Andalusia, Aragon, the Canary Islands, Cantabria, Castilla-La Mancha, Catalonia, the Autonomous Community of Madrid, the Autonomous Community of Valencia, Extremadura, La Rioja, and the Principality of Asturias) from 1980 to 2003. The ECEMC is a clinical-epidemiological research program on the causes of congenital defects, structured as a permanent registration system with a case-control design. The program is hospital-based. The defects studied were anencephaly, spina bifida, cleft lip with or without cleft palate, cleft palate only, limb reduction defects, and Down syndrome in infants born to mothers aged 34 years or older. To analyze the time trends in each Autonomous Community, the lineal trend test (chi-square with 1 degree of freedom) and chi-square with k-2 degrees of freedom to detect deviations from linearity were used. Results: The time trend of the frequencies was not the same for all the defects studied or for all the Autonomous Communities. The highest concordance between the 11 Autonomous Communities analyzed was observed in the decreasing secular trend for Down syndrome in infants born to mothers aged 34 years or older, which was statistically significant in 8 Autonomous Communities. The frequency of anencephaly significantly decreased in 6 Autonomous Communities, and in a further 2 no cases were registered. The frequency of spina bifida significantly decreased in 6 Autonomous Communities. The secular distribution of the frequencies of the other 3 types of malformations studied showed no significant trends in most of the regions. Conclusions: Since pregnancy terminations after prenatal detection of anomalies became legal in Spain, the frequency of prenatally diagnosable birth defects has clearly decreased. This decrease has not been equal in all the regions. Differences were found in the time the decreases began and in their intensity, which may reveal, among other factors, differences in health care

Maternal polymorphisms 677C-T and 1298A-C of MTHFR, and 66A-G MTRR genes: is there any relationship between polymorphisms of the folate pathway, maternal homocysteine levels, and the risk for having a child with Down syndrome?

This study was aimed at analyzing the effect of mutations in three non-synonymous SNP genes (677C > T and 1298A > C of the methylenetetrahydrofolate reductase (MTHFR) gene, and 66A > G in the MTRR gene) on total plasmatic homocysteine (Hcy), in 91 mothers of Down syndrome (DS) infants and 90 control mothers. The comparison of both groups of mothers is a new way to determine if those mutations and their interactions increase the risk for DS. Material came from the case-control network of the Spanish Collaborative Study of Congenital Malformations (ECEMC). Using a general lineal model in a backwards step, we performed the analyses including the different mutations, maternal age, the fact that each mother had a DS or a control infant, and all possible interactions of these variables, in the models, being maternal Hcy the continuous dependent variable. In another model, maternal folic acid intake during the third trimester of pregnancy was added. The results from both models were essentially the same: Hcy levels variability differs from case mothers to control ones, the presence of the MTHFR1298A > C polymorphism also affects significantly the Hcy variance, as it does the statistical interaction between the mutations MTRR66A > G and MTHFR1298A > C in the mother. In this sense, the interaction between different polymorphisms may totally modify their individual effects, and some of those effects are different in mothers of DS children and in controls' mothers. For instance, only two mutations in MTRR66 (GGAA) in mothers of control infants increase the reference maternal Hcy level in 4.66 units, and the individual effect of the genotype with only two mutations in the MTHFR1298 gene (AACC) increases the reference Hcy level in 12.74 units. However, the presence of the four mutations (GGCC) interacts giving a statistically significant decrease in 6.00 units in the level of Hcy in control mothers. On the contrary, in mothers of DS infants, the sole presence of two mutations in one of these two genes decreases the levels of Hcy (-2.31 units for GGAA genotype, and -3.43 units for AACC genotype), while the presence of the four mutations (GGCC) increases Hcy in 9.53 units. Taking into consideration that in the one-carbon metabolism cystathionine beta-synthase (CBS) catalyzes Hcy in an irreversible way, and that CBS gene is located in chromosome 21, fetuses and infants with DS have functional folate deficiency due to overexpression of CBS. This fact, as well as others influencing Hcy levels (such as nutrients interactions and lifestyle), together with the fetal genotype, suggest that their relationship with DS could be through an effect on fetal survival up to birth. Three possible mechanisms are considered by evaluating the results in the light of the present knowledge on cytology and molecular biology.