Postnatal genetic and neurodevelopmental assessment in infants born at term with severely low birth weight of non-placental origin.

OBJECTIVE: To determine the frequency of genetic syndromes and childhood neurodevelopmental impairment in non-malformed infants born at term with severely low birth weight and no evidence of placental insufficiency. METHODS: This case series was constructed from the data of infants delivered at term between 2013 and 2018 with severely low birth weight, defined as birth weight more than 2.5 SD below the mean, with normal maternal and fetal Doppler (umbilical artery, fetal middle cerebral artery, cerebroplacental ratio and uterine artery) and no maternal hypertensive disorder during pregnancy or fetal structural anomaly on prenatal ultrasound examination. Clinical exome sequencing and copy number variation (CNV) analysis were performed using DNA extracted from the children's saliva. Cognitive and psychomotor development was evaluated using the Bayley Scales of Infant and Toddler Development, 3rd edition or the Wechsler Intelligence Scale for Children, 5th edition tests, according to the child's age at testing. RESULTS: Among the 36 405 infants born within the study period, 274 (0.75%) had a birth weight below -2.5 SD, of whom 98 met the inclusion criteria. Among the 63 families contacted, seven (11%) reported a postnatal diagnosis of a genetic syndrome and a further 18 consented to participate in the study. Median gestational age at delivery was 38.0 (interquartile range (IQR), 37.3-38.5) weeks and median birth weight was 2020 (IQR, 1908-2248) g. All 18 children showed a normal result on clinical exome sequencing and CNV analysis, but six (33%) obtained a low score on neurodevelopmental testing. CONCLUSION: Non-malformed severely small term infants with no clinical or Doppler signs of placental insufficiency present a high rate of genetic syndromes and neurodevelopmental impairment during childhood. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Diagnostic yield of next-generation sequencing in fetuses with isolated increased nuchal translucency: systematic review and meta-analysis.

OBJECTIVE: To determine the diagnostic yield of exome or genome sequencing (ES/GS) over chromosomal microarray analysis (CMA) in fetuses with increased nuchal translucency (NT) and no concomitant anomalies. METHODS: This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. PubMed, Scopus and Web of Science were searched for studies describing ES/GS in fetuses with isolated increased NT. Inclusion criteria were: (1) study written in English; (2) more than two fetuses with increased NT > 99th percentile and no concomitant anomalies; and (3) a negative CMA result considered as the reference standard. Only positive variants identified on ES/GS that were classified as likely pathogenic or pathogenic and determined to be causative of the fetal phenotype were considered. Risk was assessed as the pooled effect size by single-proportion analysis using random-effects modeling (weighted by inverse of variance). RESULTS: Eleven studies reporting on the diagnostic yield of ES/GS in fetuses with isolated increased NT > 99th percentile were identified and included 309 cases. All studies were high quality according to Standards for Reporting of Diagnostic Accuracy. Overall, a pathogenic or likely pathogenic variant was identified on ES/GS in 15 fetuses, resulting in a pooled incremental yield of 4% (95% CI, 2-6%). Six (40%) of these fetuses had NT of 5 mm or more. The observed inheritance pattern was autosomal dominant in 12 cases, including four fetuses with Noonan syndrome, autosomal recessive in two cases and X-linked in one case. CONCLUSIONS: There is a 4% incremental diagnostic yield of ES/GS over CMA in fetuses with increased NT > 99th percentile without a concomitant anomaly. It is unclear whether a NT cut-off higher than 3.5 mm may be more useful in case selection for ES/GS. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Diagnostic yield of exome sequencing in fetuses with multisystem malformations: systematic review and meta-analysis.

OBJECTIVE: To determine the diagnostic yield of exome sequencing (ES) above that of chromosomal microarray analysis (CMA) or karyotyping in fetuses with multisystem structural anomalies (at least two major anomalies in different anatomical systems). METHOD: This was a systematic review conducted in accordance with PRISMA guidelines. Searching PubMed, Web of Knowledge and Cochrane database, we identified studies describing ES, whole-genome and/or next-generation sequencing in fetuses with multisystem malformations. Included were observational studies involving five or more eligible fetuses. A fetus was eligible for inclusion if it had at least two major anomalies of different anatomical systems and a negative CMA or karyotyping result. Only positive variants classified as likely pathogenic or pathogenic determined to be causative of the fetal phenotype were considered. A negative CMA or karyotype result was treated as the reference standard. The diagnostic yield of the primary outcome was calculated by single-proportion analysis using random-effects modeling. A subgroup analysis was performed to compare the diagnostic yield of the solo approach (fetus alone sequenced) with that of the trio approach (fetus and both parents sequenced). RESULTS: Seventeen articles with data on ES diagnostic yield, including 694 individuals with multisystem malformations, were identified. Overall, a pathogenic or likely pathogenic variant potentially causative of the fetal phenotype was found in 213 fetuses, giving a 33% (95% CI, 27-40%) incremental yield of ES. A stratified analysis showed similar diagnostic yields of ES using the solo approach (30%; 95% CI, 11-52%) and the trio approach (35%; 95% CI, 26-44%). CONCLUSIONS: ES applied in fetuses with multisystem structural anomalies was able to identify a potentially causative gene when CMA or karyotyping had failed to do so in an additional one-third of cases. No differences were observed between the solo and trio approaches for ES. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Genetic diversity of Ethiopian sorghum reveals signatures of climatic adaptation.

KEY MESSAGE: A large collection of Ethiopian sorghum landraces, characterized by agro-ecology and racial-group, was found to contain high levels of diversity and admixture, with significant SNP associations identified for environmental adaptation. Sorghum [Sorghum bicolor L. (Moench)] is a major staple food crop in Ethiopia, exhibiting extensive genetic diversity with adaptations to diverse agroecologies. The environmental and climatic drivers, as well as the genomic basis of adaptation, are poorly understood in Ethiopian sorghum and are critical elements for the development of climate-resilient crops. Exploration of the genome-environment association (GEA) is important for identifying adaptive loci and predicting phenotypic variation. The current study aimed to better understand the GEA of a large collection of Ethiopian sorghum landraces (n = 940), characterized with genome-wide SNP markers, to investigate key traits related to adaptation to temperature, precipitation and altitude. The Ethiopian sorghum landrace collection was found to consist of 12 subpopulations with high levels of admixture (47%), representing all the major racial groups of cultivated sorghum with the exception of kafir. Redundancy analysis indicated that agroecology explained up to 10% of the total SNP variation, and geographical location up to 6%. GEA identified 18 significant SNP markers for environmental variables. These SNPs were found to be significantly enriched (P < 0.05) for a priori QTL for drought and cold adaptation. The findings from this study improve our understanding of the genetic control of adaptive traits in Ethiopian sorghum. Further, the Ethiopian sorghum germplasm collection provides sources of adaptation to harsh environments (cold and/or drought) that could be deployed in breeding programs globally for abiotic stress adaptation.

Should cell-free DNA testing be used in pregnancy with increased fetal nuchal translucency?

OBJECTIVE: To assess the frequency of atypical chromosomal and submicroscopic anomalies, as well as fetal structural abnormalities, observed on first-trimester ultrasound scan in fetuses with nuchal translucency (NT) thickness > 99th centile, in order to evaluate the suitability of using standard cell-free DNA (cfDNA) testing as the sole screening test in these pregnancies. METHODS: This was a retrospective cohort study of 226 fetuses with NT > 99th centile at 11-14 weeks' gestation, between January 2013 and December 2017, in a clinical setting in which greater than 95% of pregnant women receive first-trimester combined screening. All patients underwent genetic testing by means of quantitative fluorescence polymerase chain reaction and chromosomal microarray analysis, mainly in chorionic villus samples. We assessed the theoretical yield of two cfDNA testing models, targeted cfDNA (chromosomes 21, 18 and 13) and extended cfDNA (chromosomes 21, 18, 13 and sex chromosomes), and compared it with that of cytogenetic testing and ultrasound assessment in the first and second or third trimesters. RESULTS: In the 226 fetuses analyzed, cytogenetic testing revealed 84 (37%) anomalies, including 68 typical aneuploidies (involving chromosomes 13, 18 or 21), six sex chromosome aneuploidies (four cases of monosomy X and two of trisomy X), three clinically relevant atypical chromosomal anomalies (one trisomy 22, one trisomy 21 mosaicism and one unbalanced translocation), five submicroscopic pathogenic variants and two cases with Noonan syndrome. Targeted and extended cfDNA testing would miss at least 12% (10/84) and 19% (16/84), respectively, of genetic anomalies, accounting for 4.4% and 7.1% of the fetuses with an increased NT, respectively. Finally, of the 142 fetuses with no identified genetic anomaly, a major fetal malformation was observed in 15 (10.6%) fetuses at the early anomaly scan, and in 19 (13.4%) in the second or third trimester. CONCLUSIONS: cfDNA does not appear to be the appropriate genetic test in fetuses with NT > 99th centile, given that it would miss 12-19% of genetic anomalies in this group. Additionally, first-trimester ultrasound will identify a major structural abnormality in 11% of the fetuses with NT > 99th centile and no genetic anomaly. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Performance of fetal middle cerebral artery peak systolic velocity for prediction of anemia in untransfused and transfused fetuses: systematic review and meta-analysis.

OBJECTIVE: To evaluate the performance of fetal middle cerebral artery peak systolic velocity (MCA-PSV) ≥ 1.5 multiples of the median (MoM) for the prediction of moderate-severe anemia, in untransfused and transfused fetuses. METHODS: A systematic search was performed to identify relevant observational studies reported in the period 2008-2018 that evaluated the performance of MCA-PSV, using a threshold of 1.5 MoM for the prediction of fetal anemia. Diagnosis of fetal anemia by blood sampling was the reference standard. A hierarchical summary receiver-operating characteristics (hSROC) curve was constructed using random-effects modeling. Subgroup and meta-regression analyses, according to the number of previous intrauterine transfusions, were performed. RESULTS: Twelve studies and 696 fetuses were included in the meta-analysis. The area under the hSROC curve (AUC) for moderate-severe anemia was 83%. Pooled sensitivity and specificity (95% CI) were 79% (70-86%) and 73% (62-82%), respectively, and positive and negative likelihood ratios were 2.94 (95% CI, 2.13-4.00) and 0.272 (95% CI, 0.188-0.371). When considering only untransfused fetuses, prediction improved, achieving an AUC of 87%, sensitivity of 86% (95% CI, 75-93%) and specificity of 71% (95% CI, 49-87%). A decline in sensitivity for the prediction of moderate-severe anemia by MCA-PSV ≥1.5 MoM was observed (estimate, -5.5% (95% CI, -10.7 to -0.3%), P = 0.039) as the number of previous transfusions increased. CONCLUSIONS: MCA-PSV ≥ 1.5 MoM for the prediction of moderate-severe anemia in untransfused fetuses shows moderate accuracy (86% sensitivity and 71% specificity), which declines with increasing number of intrauterine transfusions. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Rendimiento de la velocidad sistólica máxima de la arteria cerebral media fetal para la predicción de la anemia en fetos sometidos a transfusión y no sometidos: revisión sistemática y metaanálisis OBJETIVOS: Estimar las diferencias en la frecuencia del diagnóstico del útero septo mediante tres definiciones diferentes y determinar si estas diferencias son significativas en la práctica clínica, y examinar la relación entre el diagnóstico del útero septo, por medio de cada una de las tres definiciones, y la infertilidad o el aborto espontáneo previo, así como con el costo de la recomendación de cirugía. MÉTODOS: Este estudio fue un análisis secundario de los datos de un estudio prospectivo de 261 mujeres en edad reproductiva que asisten de forma consecutiva a una clínica privada especializada en el diagnóstico y tratamiento de las malformaciones congénitas del útero. El nuevo análisis de los conjuntos de datos se realizó de acuerdo con tres maneras diferentes de definir el útero septo: siguiendo las recomendaciones de la Sociedad Americana de Medicina Reproductiva (ASRM, por sus siglas en inglés), una actualización de 2016 de las de la Sociedad Americana de la Fertilidad de 1988 (ASRM-2016: profundidad de la hendidura interna del fondo uterino ≥1,5 cm, ángulo de la hendidura interna <90o y profundidad de la hendidura externa <1 cm); con base en las recomendaciones de la Sociedad Europea para la Reproducción Humana y Embriología/Sociedad Europea de Endoscopía Ginecológica (ESHRE/ESGE, por sus siglas en inglés), publicadas en 2013 y revisadas en 2016 (ESHRE/ESGE-2016: profundidad de la hendidura interna del fondo uterino >50% del espesor de la pared uterina y profundidad de la hendidura externa <50% del espesor de la pared uterina, cuando se mide el espesor de la pared uterina por encima de la línea interostial/intercornual); y utilizando una definición publicada el año pasado que se basaba en la decisión tomada con mayor frecuencia por un grupo de expertos (Malformación Uterina Congénita según los Expertos; CUME, por sus siglas en inglés) (CUME-2018: profundidad de la hendidura interna del fondo uterino ≥1 cm y profundidad de la hendidura externa del fondo uterino <1cm). Se comparó la tasa de diagnóstico del útero septo utilizando cada una de estas tres definiciones y, para cada una, se estimó la relación entre el diagnóstico y la infertilidad y/o el aborto espontáneo previo, y se anticiparon los costos asociados con su implementación mediante un método de estimación conjetural. RESULTADOS: Aunque el 32,6% (85/261) de las mujeres cumplieron con los criterios de una de las tres definiciones de útero septo, sólo el 2,7% (7/261) de ellas se pudieron definir como con útero septo de acuerdo con las tres definiciones. Significativamente, se diagnosticaron más casos de útero septo usando los criterios de ESHRE/ESGE-2016 que usando los de ASRM-2016 (31% vs 5%, riesgo relativo (RR)=6,7, P<0.0001) o de CUME-2018 (31% vs 12%, RR=2,6, P<0.0001). También se observaron casos frecuentes que no pudieron ser clasificados definitivamente por ASRM-2016 (zona gris: ni normal/arcuado ni septo; 6,5%). No hubo diferencias significativas (P>0,05) en la prevalencia de útero septo en mujeres con infertilidad vs mujeres fértiles, según ASRM-2016 (5% vs 4%), ESHRE/ESGE-2016 (35% vs 28%) o CUME-2018 (11% vs 12%). El diagnóstico del útero septo fue significativamente más frecuente en mujeres con aborto espontáneo previo, según los criterios de ASRM-2016 (11% vs 3%; P=0,04) y de CUME-2018 (22 vs 10%; P=0,04), pero no según los criterios de ESHRE/ESGE-2016 (42% vs 28%; P=0,8). Los cálculos mostraron que los costos globales para el sistema de salud dependerían en gran medida de los criterios utilizados desde el punto de vista clínico para definir el útero septo, siendo los costos asociados con la definición de ESHRE/ESGE-2016 potencialmente de 100-200 mil millones de dólares adicionales durante 5 años, en comparación con los asociados a las definiciones ASRM-2016 y CUME-2018. CONCLUSIONES: La prevalencia del útero septo según las definiciones de ESHRE/ESGE-2016, ASRM-2016 y CUME-2018 difiere considerablemente. Una limitación importante de la clasificación ASRM, que debe ser abordada, es la alta proporción de casos no clasificables originalmente denominados, por nosotros, como en la 'zona gris'. La alta tasa de sobrediagnóstico del útero septo en función de ESHRE/ESGE-2016 puede llevar a un uso innecesario de la cirugía y, por lo tanto, a un riesgo innecesario en estas mujeres y puede imponer una carga financiera considerable a los sistemas sanitarios. Se deben fomentar los esfuerzos para definir criterios clínicamente significativos y aplicables de forma universal para el diagnóstico del útero septo.

Added value of chromosomal microarray analysis over conventional karyotyping in stillbirth work-up: systematic review and meta-analysis.

OBJECTIVE: To assess the added value of chromosomal microarray analysis (CMA) over conventional karyotyping to assess the genetic causes in stillbirth. METHODS: To identify relevant studies, published in English or Spanish and without publication time restrictions, we performed a systematic search of PubMed, SCOPUS and ISI Web of Science databases, The Cochrane Library and the PROSPERO register of systematic reviews, for case series of fetal loss ≥ 20 weeks of gestation, with normal or suspected normal karyotype, undergoing CMA and with at least five subjects analyzed. To investigate quality, two reviewers evaluated independently the risk of bias using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. For the meta-analysis, the incremental yield of CMA over karyotyping was assessed by single-proportion analysis using a random-effects model (weighting by inverse variance). We assessed heterogeneity between studies and performed a sensitivity analysis and a subgroup analysis of structurally abnormal (malformed or growth-restricted) and normal fetuses. RESULTS: Included in the meta-analysis were seven studies involving 903 stillborn fetuses which had normal karyotype. The test success rate achieved by conventional cytogenetic analysis was 75%, while that for CMA was 90%. The incremental yield of CMA over conventional karyotyping based on the random-effects model was 4% (95% CI, 3-5%) for pathogenic copy-number variants (pCNVs) and 8% (95% CI, 4-17%) for variants of unknown significance. Subgroup analysis showed a 6% (95% CI, 4-10%) incremental yield of CMA for pCNVs in structurally abnormal fetuses and 3% (95% CI, 1-5%) incremental yield for those in structurally normal fetuses. The pCNV found most commonly was del22q11.21. CONCLUSIONS: CMA, incorporated into the stillbirth work-up, improves both the test success rate and the detection of genetic anomalies compared with conventional karyotyping. To achieve a genetic diagnosis in stillbirth is particularly relevant for the purpose of counseling regarding future pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Valor añadido del análisis de microarrays cromosómicos sobre el cariotipado convencional en el estudio de éxitus fetal: revisión sistemática y metaanálisis OBJETIVO: Evaluar el valor añadido del análisis de microarrays cromosómicos (AMC) sobre el cariotipado convencional para evaluar las causas genéticas en el éxitus fetal. MÉTODOS: Para identificar estudios relevantes, publicados en inglés o español y sin restricciones de tiempo de la publicación, se realizó una búsqueda sistemática en las bases de datos PubMed, SCOPUS e ISI Web of Science, The Cochrane Library y el registro de revisiones sistemáticas PROSPERO, para series de casos de pérdida fetal ≥ 20 semanas de gestación, con cariotipo normal o presuntamente normal, sometidos a AMC y con al menos cinco sujetos analizados. Para investigar la calidad, dos revisores evaluaron de forma independiente el riesgo de sesgo mediante la herramienta Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Para el metaanálisis, se evaluó el rendimiento incremental del AMC sobre el cariotipado mediante un análisis de proporción única que empleó un modelo de efectos aleatorios (ponderación por varianza inversa). Se evaluó la heterogeneidad entre los estudios y se realizó un análisis de sensibilidad y un análisis de subgrupos de fetos estructuralmente anómalos (con malformación o con restricción del crecimiento) y normales. RESULTADOS: En el metaanálisis se incluyó siete estudios que comprendían 903 casos de éxitus fetal con cariotipo normal. La tasa de éxito de la prueba alcanzada mediante el análisis citogenético convencional fue del 75%, mientras que la del AMC fue del 90%. El rendimiento incremental del AMC sobre el cariotipado convencional en el modelo de efectos aleatorios fue del 4% (IC 95%, 3-5%) para las variantes patógenas del número de copias (VNCp) y del 8% (IC 95%, 4-17%) para las variantes de significancia desconocida. El análisis de subgrupos mostró un rendimiento incremental del AMC del 6% (IC 95%, 4-10%) para los fetos estructuralmente anormales y del 3% (IC 95%, 1-5%) para los fetos estructuralmente normales. La VNCp encontrada más comúnmente fue del22q11.21. CONCLUSIONES: El AMC, incorporado en el estudio del éxitus fetal, mejora tanto la tasa de éxito de las pruebas como la detección de anomalías genéticas en comparación con el cariotipado convencional. El diagnóstico genético en el éxitus fetal es especialmente relevante para el asesoramiento en futuros embarazos.

Added value of chromosomal microarray analysis over karyotyping in early pregnancy loss: systematic review and meta-analysis.

OBJECTIVE: To estimate the increased test success rate and incremental yield of chromosomal microarray analysis (CMA) over conventional karyotyping in detection of pathogenic copy number variants (CNVs) and variants of unknown significance (VOUS) in early pregnancy loss. METHOD: This was a systematic review conducted in accordance with PRISMA criteria. All articles identified in PubMed, Ovid MEDLINE and Web of Science, between January 2000 and April 2017, that described CNVs in early pregnancy losses (up to 20 weeks) were included. Risk differences were pooled to estimate the incremental yield of CMA over karyotyping overall, and after stratification. In addition, test success rate, defined as the proportion of informative results, was compared in series in which CMA and karyotyping were performed concurrently. RESULTS: Twenty-three studies, reporting on 5507 pregnancy losses up to 20 weeks with full data available, met the inclusion criteria for analysis. In the series in which CMA and karyotyping were performed concurrently, CMA showed a significant improvement in success rate, providing informative results in 95% (95% CI, 94-96%) of cases compared with karyotyping in which informative results were provided in 68% (95% CI, 66-70%) of cases. Combined data from reviewed studies revealed that incremental yields of CMA over karyotyping were 2% (95% CI, 1-2%) for pathogenic CNVs and 4% (95% CI, 3-6%) for VOUS. The most common pathogenic CNVs reported were 22q11.21 and 1p36.33 deletion. CONCLUSION: In comparison with conventional karyotyping, CMA provides a significant increase in test success rate and incremental diagnostic yield in early pregnancy loss. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Counting ovarian antral follicles by ultrasound: a practical guide.

This Consensus Opinion summarizes the main aspects of several techniques for performing ovarian antral follicle count (AFC), proposes a standardized report and provides recommendations for future research. AFC should be performed using a transvaginal ultrasound (US) probe with frequency ≥ 7 MHz. For training, we suggest a minimum of 20-40 supervised examinations. The operator should be able to adjust the machine settings in order to achieve the best contrast between follicular fluid and ovarian stroma. AFC may be evaluated using real-time two-dimensional (2D) US, stored 2D-US cine-loops and stored three-dimensional (3D) US datasets. Real-time 2D-US has the advantage of permitting additional maneuvers to determine whether an anechoic structure is a follicle, but may require a longer scanning time, particularly when there is a large number of follicles, resulting in more discomfort to the patient. 2D-US cine-loops have the advantages of reduced scanning time and the possibility for other observers to perform the count. The 3D-US technique requires US machines with 3D capability and the operators to receive additional training for acquisition/analysis, but has the same advantages as cine-loop and also allows application of different imaging techniques, such as volume contrast imaging, inversion mode and semi-automated techniques such as sonography-based automated volume calculation. In this Consensus Opinion, we make certain recommendations based on the available evidence. However, there is no strong evidence that any one method is better than another; the operator should choose the best method for counting ovarian follicles based on availability of resources and on their own preference and skill. More studies evaluating how to improve the reliability of AFC should be encouraged. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Post-head-emergence frost in wheat and barley: defining the problem, assessing the damage, and identifying resistance.

Radiant frost is a significant production constraint to wheat (Triticum aestivum) and barley (Hordeum vulgare), particularly in regions where spring-habit cereals are grown through winter, maturing in spring. However, damage to winter-habit cereals in reproductive stages is also reported. Crops are particularly susceptible to frost once awns or spikes emerge from the protection of the flag leaf sheath. Post-head-emergence frost (PHEF) is a problem distinct from other cold-mediated production constraints. To date, useful increased PHEF resistance in cereals has not been identified. Given the renewed interest in reproductive frost damage in cereals, it is timely to review the problem. Here we update the extent and impacts of PHEF and document current management options to combat this challenge. We clarify terminology useful for discussing PHEF in relation to chilling and other freezing stresses. We discuss problems characterizing radiant frost, the environmental conditions leading to PHEF damage, and the effects of frost at different growth stages. PHEF resistant cultivars would be highly desirable, to both reduce the incidence of direct frost damage and to allow the timing of crop maturity to be managed to maximize yield potential. A framework of potential adaptation mechanisms is outlined. Clarification of these critical issues will sharpen research focus, improving opportunities to identify genetic sources for improved PHEF resistance.

Variation in δ15 N and δ13 C stable isotope values in common dolphins (Delphinus spp.) worldwide, with particular emphasis on the eastern North Atlantic populations.

RATIONALE: Distinguishing population units of small cetaceans continuously distributed in a widespread area is challenging but critical for their conservation and management. The use of chemical markers allows the investigation of foraging ecology and inter-specific variability, in order to detect population structure and niche segregation in the common dolphin (Delphinus spp.). METHODS: The stable isotope ratios of carbon (δ(13)C values) and nitrogen (δ(15)N values) were measured in the bone tissue of common dolphins accidentally by-caught or stranded along the north-eastern and eastern Subtropical Atlantic Ocean, by means of continuous flow elemental analyser/isotope ratio mass spectrometry. Trophic positions were determined and compared, taking into account the local ecosystem trophic baseline for each study area. Data obtained for the study areas were qualitatively compared with those for common dolphin species/populations distributed worldwide. RESULTS: The δ(13)C and δ(15)N values were higher in the eastern Subtropical Atlantic as a consequence of the coexistence in the area of the common dolphin short- and long-beaked morphotypes. Individuals from the north-eastern Atlantic displayed lower δ(15)N values, reflecting dissimilarities in diet and variation in local isotopic baselines. Comparisons with other areas around the world suggest that the species is extremely adaptive and feeds at different trophic levels to adapt to local variations. CONCLUSIONS: Stable isotopes are a useful tool to investigate population structure and trophic niche segregation. The trophic behaviour of worldwide populations of common dolphins was fruitfully analysed and revealed substantial differences, probably reflective of both adaptive strategies of the genus and dissimilarities in the structure of the ecosystems.

Further insights into diastolic dysfunction in first-trimester trisomy-21 fetuses.

OBJECTIVE: To assess fetal cardiac function in first-trimester trisomy-21 fetuses as compared with fetuses with other aneuploidies, euploid fetuses with cardiac defects or isolated increased nuchal translucency (NT) and controls. METHODS: During a 2.5-year period, NT, ductus venosus (DV) blood flow, diastolic filling time, early filling time, tricuspid flow, tricuspid and mitral valve E/A velocity ratios, left ventricle shortening fraction, left myocardial performance index and fetal heart rate were assessed in fetuses with a crown-rump length between 45 and 84 mm undergoing chorionic villus sampling at our center. Cardiac parameters among study groups were compared with the use of 95% CIs. RESULTS: The study population comprised 28 fetuses with trisomy 21, 25 with other aneuploidies, 94 euploid fetuses with abnormal findings (27 with cardiac defects, 31 with other structural anomalies and 36 with isolated increased NT) and 271 controls. Trisomy-21 fetuses showed signs of diastolic dysfunction such as increased DV pulsatility index and E/A ratios together with a higher prevalence of tricuspid regurgitation. However, no differences were found in euploid fetuses with cardiac defects or isolated increased NT. CONCLUSIONS: No signs of cardiac dysfunction were observed in euploid fetuses with increased NT or cardiac defects, while in trisomy-21 fetuses signs of diastolic dysfunction could be potentially attributed to volume overload.

Genomic microarray in fetuses with increased nuchal translucency and normal karyotype: a systematic review and meta-analysis.

OBJECTIVE: To estimate the incremental yield of detecting copy number variants (CNVs) by genomic microarray over karyotyping in fetuses with increased nuchal translucency (NT) diagnosed by first-trimester ultrasound. METHODS: This was a systematic review conducted in accordance with PRISMA criteria. We searched PubMed, Ovid MEDLINE and Web of Science for studies published between January 2009 and January 2015 that described CNVs in fetuses with increased NT, usually defined as ≥ 3.5 mm, and normal karyotype. Search terms included: fetal or prenatal, nuchal translucency or cystic hygroma or ultrasound anomaly, array comparative genomic hybridization or copy number variants, with related search terms. Risk differences were pooled to estimate the overall and stratified microarray incremental yield using RevMan. Quality assessment of included studies was performed using the Quality Assessment tool for Diagnostic Accuracy Studies (QUADAS-2) checklist. RESULTS: Seventeen studies met the inclusion criteria for analysis. Meta-analysis indicated an incremental yield of 5.0% (95% CI, 2.0-8.0%) for the detection of CNVs using microarray when pooling results. Stratified analysis of microarray results demonstrated a 4.0% (95% CI, 2.0-7.0%) incremental yield in cases of isolated NT and 7.0% (95% CI, 2.0-12.0%) when other malformations were present. The most common pathogenic CNVs reported were 22q11.2 deletion, 22q11.2 duplication, 10q26.12q26.3 deletion and 12q21q22 deletion. The pooled prevalence for variants of uncertain significance was 1%. CONCLUSION: The use of genomic microarray provides a 5.0% incremental yield of detecting CNVs in fetuses with increased NT and normal karyotype.

Array comparative genomic hybridization and fetal congenital heart defects: a systematic review and meta-analysis.

OBJECTIVE: Array comparative genomic hybridization (aCGH) is a molecular cytogenetic technique that is able to detect the presence of copy number variants (CNVs) within the genome. The detection rate of imbalances by aCGH compared to standard karyotyping and 22q11 microdeletion analysis by fluorescence in-situ hybridization (FISH), in the setting of prenatally-diagnosed cardiac malformations, has been reported in several studies. The objective of our study was to perform a systematic literature review and meta-analysis to document the additional diagnostic gain of using aCGH in cases of congenital heart disease (CHD) diagnosed by prenatal ultrasound examination, with the aim of assisting clinicians to determine whether aCGH analysis is warranted when an ultrasonographic diagnosis of CHD is made, and to guide counseling in this setting. METHODS: Articles in PubMed, EMBASE and Web of Science databases from January 2007 to September 2014 describing CNVs in prenatal cases of CHD were included. Search terms were: 'array comparative genomic hybridization', 'copy number variants' and 'fetal congenital heart defects'. Articles regarding karyotyping or 22q11 deletion only were excluded. RESULTS: Thirteen publications (including 1131 cases of CHD) met the inclusion criteria for the analysis. Meta-analysis indicated an incremental yield of 7.0% (95% CI, 5.3-8.6%) for the detection of CNVs using aCGH, excluding aneuploidy and 22q11 microdeletion cases. Subgroup results showed a 3.4% (95% CI, 0.3-6.6%) incremental yield in isolated CHD cases, and 9.3% (95% CI, 6.6-12%) when extracardiac malformations were present. Overall, an incremental yield of 12% (95% CI, 7.6-16%) was found when 22q11 deletion cases were included. There was an additional yield of 3.4% (95% CI, 2.1-4.6%) for detecting variants of unknown significance (VOUS). CONCLUSIONS: In this review we provide an overview of published data and discuss the benefits and limitations of using aCGH. If karyotyping and 22q11 microdeletion analysis by FISH are normal, using aCGH has additional value, detecting pathogenic CNVs in 7.0% of prenatally diagnosed CHD, with a 3.4% additional yield of detecting VOUS.