The reduced use of invasive procedures leads to a change of frequencies of prenatally detected chromosomal aberrations: population data from the years 2012-2016.

OBJECTIVE: The aim of the study was to analyze the results of screening for chromosomal aberrations in a population with a high rate of first-trimester screening and low rate of cell-free DNA testing. METHODS: The data were obtained from the National Registry of Congenital Anomalies of the Czech Republic. We calculated and compared the proportion of autosomal trisomies (Down, Edwards, and Patau syndrome) and of other chromosomal aberrations identified during prenatal diagnostics. RESULTS: We identified 3009 prenatally diagnosed cases of chromosomal aberrations in the 2012-2016 period. The number of major autosomal trisomies has increased from 329 cases (30.86 per 10,000 live births) in 2012 to 423 cases (37.41) in 2016 (p = 0.014). The numbers of other aberrations decreased from 246 cases (23.07 per 10,000) in 2012 to 217 cases (19.19) in 2016 (p = 0.017). The usage of invasive diagnostic procedures decreased from 1099.54 in 2012 to 622.73 in 2016 (per 10,000 live births). CONCLUSIONS: Our population-based study confirmed a decrease in prenatal detection of nonmajor chromosomal aberrations wherein a decrease of invasive testing occurred. With the introduction of cell-free DNA testing, further decrease of invasive procedures and detection of nonmajor aberrations may be expected.

Congenital anomalies in children born in the Czech Republic in 1994-2015.

ÚVOD Populace je v současné vystavena různým zevním vlivům, ze kterých mohou vyplývat i různá zdravotní rizika. Jedním z možných je i riziko vzniku vrozené vady (VV). Z hlediska studia zdravotního stavu populace je důležitá znalost nejen průměrných celkových incidencí VV, ale i případných změn těchto incidencí v průběhu času. Incidence VV je považována za jeden ze základních kvalitativních ukazatelů populačních i medicínských (1). Nelze opomenout ani hledání potenciálních rizik vedoucích ke zvýšené pravděpodobnosti výskytu VV. Těmito riziky mohou být nežádoucí vlivy zevního prostředí nebo faktory biologicko-sociální (věk žen, jejich onemocnění aj). Podíl jednotlivých typů VV u narozených dětí se v čase mění, obdobně jako struktura příčin úmrtí. Z hlediska epidemiologického je nutné hodnotit incidence VV a jejich změny především z pohledu jednotlivých diagnóz. Během posledních let se intenzita VV v Česku měnila. U některých typů se četnost v novorozenecké populaci snižuje díky úspěšné prenatální diagnostice, u jiných diagnóz naopak četnost u narozených dětí stoupá (2). Kromě prenatální diagnostiky se však na výsledné četnosti VV v populaci mohou uplatňovat i další vlivy. Jedním z nich může být i zlepšení, zrychlení a zkvalitnění postnatálních diagnostických možností - především zavedení a rozvoj ultrazvukové diagnostiky (3). Úspěšnost prenatální diagnostiky a četnost VV u narozených jsou rovněž významným ukazatelem prenatální a perinatální péče, přežívání dětí narozených s VV pak ukazatelem péče postnatální (především neonatální a chirurgické). Registrace vrozených vad má v České republice dlouhou tradici - Národní registr vrozených vad zahájil svou činnost již před více než půlstoletím, v roce 1964 (4).   METODIKA Retrospektivní epidemiologická studie využívá oficiální data z Národního registru vrozených vad vedeného v rámci Registru reprodukčního zdraví v Ústavu zdravotnických informací a statistiky ČR (ÚZIS). Analyzovány byly incidence jednotlivých diagnóz vrozených vad (kódy Q00-Q99) u narozených dětí z celého území České republiky za časové období 1994-2015. Incidence VV byly analyzovány pro obě pohlaví, a to jak celkově (pro celou skupinu diagnóz VV), tak i dle základních diagnostických skupin Mezinárodní klasifikace nemocí (MKN).   VÝSLEDKY V období 1994-2015 se dle údajů ÚZIS ČR narodilo v České republice celkem 87 359 dětí s vrozenou vadou zjištěnou do 1 roku života. Z tohoto celkového počtu bylo 51 315 chlapců a 36 030 dívek. U 14 případů nebylo pohlaví známé / zjištěno. Vývoj počtu diagnostikovaných případů ukazují přehledně první tři grafy (obr. 1-3), zvlášť pro chlapce, dívky a celkově. V relativních počtech to bylo za celé sledované období průměrně 385,4 na 10 000 živě narozených dětí: nejméně 242,5 v roce 1994, nejvíce pak 448,3 v roce 2011. V případě živě narozených chlapců to bylo nejméně 263,6 v roce 1994, nejvíce pak 533,3 v roce 2011; průměrná hodnota činila 440,6 na 10 000. U živě narozených dívek byla průměrná hodnota za sledované období 327,1 na 10 000 ; nejnižší hodnota 220,1 byla zaznamenána opět v roce 1994, nejvyšší hodnota 380,9 v roce 2003. Grafy na obr. 4-6 ukazují relativní počty na 10 000 živě narozených v průběhu sledovaného období, opět zvlášť pro chlapce, dívky a celkově. Další část naší analýzy se věnovala změnám v průběhu sledovaného období pro jednotlivé skupiny diagnóz dle rozdělení v Mezinárodní klasifikaci nemocí, 10. verze (tab. 1). various types of congenital anomalies are changing during the time according to different factors. Three main factors are methodical changes of the registration process, improvement of prenatal diagnostics and the real changes of incidences of selected diagnoses. While in the previous time period (till 1993) the registry included only selected diagnoses of congenital anomalies, in the new period (starting 1994) the registry includes all diagnoses of congenital anomalies from the ICD-10 classification. We can also see the difference in the incidences from 1994-1999 and 2000-2015 time period. The reason for this difference is the methodical change of registration, the Registry of congenital anomalies also receives the notifications about possible anomalies from the report of newborn (even when the report of congenital anomaly was not sent). As for the prenatal diagnostics - we may analyse possible changes of incidences - if the specific defect can be diagnosed prenatally.

Prenatal diagnostics of chromosomal aberrations in the Czech Republic: Actual data and important trends.

The main goal of this study was to analyse the spectrum of chromosomal aberrations that were diagnosed during prenatal diagnostics in the Czech Republic in 2016. We present a retrospective epidemiological analysis that is based on the official data from the National Registry of Congenital Anomalies that is run by the Institute of Health Information and Statistics of the Czech Republic. Additional data were obtained actively from the departments of medical genetics and prenatal diagnostics under the guidance of the Czech Society of Medical Genetics and Genomics. In 2016 there were 577 cases of chromosomal aberrations identified during prenatal diagnostics in the Czech Republic. The most important group of aberrations were the three main autosomal trisomies - Down, Edwards and Patau syndromes which were identified in 64.8 % of cases. The most frequent of them was the Down syndrome, that was identified in 271 cases (47 % of all cases identified in 2016). Other aberrations (including the abnormalities of the gonosomes and other autosomal anomalies) were still identified in more than one third of cases, although the screening programs do not primarily focus on them. Combined screening in the first trimester and following prenatal diagnostics mostly identify main autosomal trisomies. Screening is currently the most important clinical referral for the invasive prenatal diagnostics procedures. We also observe important time trend of decreasing numbers of invasive diagnostics procedures - while the overall prenatal detection rate of chromosomal aberrations is not negatively affected. Keywords: hromosomal aberrations, prenatal diagnostics, prenatal screening.

Importance of the integrated test in the Down's syndrome screening algorithm.

OBJECTIVE: In the Czech Republic, over 97% of all pregnant women undergo some type of antenatal screening for Down's syndrome. In about 95% of cases with a confirmed fetal chromosomal abnormality, the pregnancy is terminated. The most commonly used test is the first trimester combined test. We investigated the impact of implementing an integrated sequential test to improve the detection of Down's syndrome pregnancies. METHODS: Data on the incidence of congenital defects, number of births, and affected pregnancies terminated are recorded in the National Registry of Congenital Anomalies. Anonymous data on cases of Down's syndrome diagnosed antenatally or postnatally between 2010 and 2015 in one of the large antenatal care centers were analyzed. RESULTS: There were 600 diagnoses of Down's syndrome (5.7 per 1000 births), 90% of which were made antenatally. Of antenatally detected cases, 80% were indicated for diagnostic procedure by multimarker screening results. In the multimarker screen positive group, 75% cases were first trimester positive and 25% second trimester positive (most of these had positive integrated test results). Among Down's syndrome cases indicated for antenatal diagnosis by multimarker screening results 6.25% (n = 26) were first trimester negative, and became positive after integration with the second trimester screening results. CONCLUSIONS: Results from five major Czech antenatal centers confirm that an integrated sequential test would detect 80-85% of Down's syndrome fetuses in the first trimester and at least an extra 5-10% of Down's syndrome pregnancies in the second trimester of pregnancy. These are important data that should be considered in implementing the national antenatal screening program.

MECP2 mutations in Czech patients with Rett syndrome and Rett-like phenotypes: novel mutations, genotype-phenotype correlations and validation of high-resolution melting analysis for mutation scanning.

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder characterized by developmental regression with loss of motor, communication and social skills, onset of stereotypic hand movements and often seizures. RTT is primarily caused by de novo mutations in the methyl-CpG-binding protein 2 gene (MECP2). We established a high-resolution melting (HRM) technique for mutation scanning of the MECP2 gene and performed analyses in Czech patients with RTT, autism spectrum conditions and intellectual disability with Rett-like features. In the cases with confirmed MECP2 mutations, we determined X-chromosome inactivation (XCI), examined the relationships between genotype and clinical severity and evaluated the modifying influence of XCI. Our results demonstrate that HRM analysis is a reliable method for the detection of point mutations, small deletions and duplications in the MECP2 gene. We identified 29 pathogenic mutations in 75 girls, including four novel mutations: c.155_1189del1035;909_932inv;insC, c.573delC, c.857_858dupAA and c.1163_1200del38. Skewed XCI (ratio >75%) was found in 19.3% of the girls, but no gross divergence in clinical severity was observed. Our findings confirm a high mutation frequency in classic RTT (92%) and a correlation between the MECP2 mutation type and clinical severity. We also demonstrate limitations of XCI in explaining all of the phenotypic differences in RTT.

[Prevalence of selected congenital anomalies in the Czech Republic: renal and cardiac anomalies and congenital chromosomal aberrations]. / Prevalence vybraných vrozených vad v Ceské republice: vývojové vady ledvin, srdce a vrozené chromozomové aberace.

STUDY GOAL: Analysis of the prevalence rates of selected diagnoses of congenital anomalies in the Czech Republic in 1994-2009. STUDY TYPE: Retrospective epidemiological analysis of postnatal and total (including prenatally diagnosed cases) prevalence of congenital anomalies from the database of the National Registry of Congenital Anomalies of the Czech Republic. MATERIAL AND METHODS: Data from the National Registry of Congenital Anomalies (NRCA) maintained by the Institute of Health Information and Statistics of the Czech Republic (IHIS CR) were used. Data on congenital anomalies in general and selected types of congenital anomalies were analyzed for the entire Czech Republic from 1994-2009. Additional data on prenatally diagnosed anomalies were obtained from medical genetics centres in the Czech Republic thanks to voluntary cooperation. This study analyzed postnatal and overall prevalence of congenital anomalies, with the latter including results of positive prenatal diagnosis. More detailed analysis was carried out for the following diagnoses: cystic kidney disease, renal agenesis/hypoplasia, tetralogy of Fallot, large vessel transposition, left heart hypoplasia, aortic coarctation, Down syndrome, Edward syndrome, and Patau syndrome. RESULTS: Cystic kidney disease showed a significant increase in 1999 and 2000, mainly due to postnatally diagnosed cases. This can be explained, on the one hand, by the modification made to the reporting of congenital anomalies in the Czech Republic and, on the other hand, by an earlier and more complete detection of postnatal cases. Since 2000, there has been a significant increase in reported cystic kidney disease as a result of postnatal kidney screening. In 1994-1999, the prevalence rates of this diagnosis ranged from 1.7 to 3.1 per 10,000 live births. Similar trend is seen in the prevalence of renal agenesis/hypoplasia. In the monitored period, prenatally diagnosed cases showed a slight increase while postnatally diagnosed cases showed a considerable rise. In 1994-1999, the prevalence rates of renal agenesis/hypoplasia ranged between 1.7 and 3.0 per 10,000 live births and in 2000-2009, between 3.9 and 7.7 per 10,000 live births. A major contributor to the upward trend is more frequent detection of unilateral renal agenesis/hypoplasia. The prevalence of tetralogy of Fallot remains nearly unchanged, with prenatally diagnosed cases accounting for more than 20% since 2000. The mean postnatal prevalence rate was 3.20 per 10,000 live births and the overall prevalence rate was 3.54 per 10,000 live births. A similar prevalence trend is seen in large vessel transposition. The mean postnatal prevalence rate was 3.01 per 10,000 live births and the mean overall prevalence rate was 3.38 per 10,000 live births. The proportion of prenatally diagnosed left heart hypoplasia showed a slow upward trend, reaching more than 75% in 2006. The mean postnatal prevalence rate was 1.44 per 10,000 live births and the mean overall prevalence rate was 2.86 per 10,000 live births. Aortic coarctation was diagnosed prenatally most often in 2003 (15.25%), with a mean of 7.5% for the whole period analyzed. Despite the prenatal diagnostic outcomes, the postnatal prevalence rates of left heart hypoplasia did not substantially vary in 1994-2009. The mean postnatal prevalence rate was 4.87 per 10,000 live births and the mean overall prevalence rate was 5.26 per 10,000 live births. The prevalence rates of prenatally diagnosed Down syndrome were continuously increasing from 4.79 to 17.73 per 10,000 live births and conversely, the postnatal prevalence rates were continuously decreasing from 7.79 to 3.31 per 10,000 live births. Increase in the overall prevalence rates can be explained mainly by the demographic situation in the Czech Republic in recent years: the average age at first birth and the first birth rate for women aged over 35 years were on the rise. The rate of prenatally diagnosed Down syndrome doubled from 40% to 80%. Similarly, the prevalence rate of prenatally diagnosed Edwards syndrome was on the rise while that of postnatally diagnosed cases was declining. The rate of prenatally diagnosed cases rose from 63% to 96% over the last two years. The mean prevalence rate of postnatally diagnosed cases was 0.72 per 10,000 live births and the mean overall prevalence rate was 3.78 per 10,000 live births. Similarly, the rate of prenatally diagnosed Patau syndrome increased from 30% in 1997 to 100% in 2009 and the rate of postnatally diagnosed cases was declining. The mean prevalence rate of postnatally diagnosed cases was 0.40 per 10,000 live births and the mean overall prevalence rate was 1.38 per 10,000 live births. CONCLUSION: The overall prevalence rates of the monitored diagnoses from the group of congenital kidney disease (cystic kidney disease and renal agenesis/hypoplasia) were on the rise in the monitored -period mainly due to advances in imaging technologies (ultrasonography) and their use in both prenatal and postnatal diagnosis. Increase in postnatally diagnosed cases can be attributed primarily to the reporting of less severe cases (cystic kidney disease) or unilateral anomalies (renal agenesis and hypoplasia). As for the monitored congenital heart defects, advances in ultrasonographic imaging diagnosis played a considerable role in the increase of cases. The overall prevalence rate show a slow upward trend, but there is a significant decline in postnatally diagnosed cases due to prenatal diagnosis of a severe anomaly, left heart hypoplasia. As for congenital chromosomal aberrations, several interconnected factors influenced the final rate. Firstly, the proportion of prenatally diagnosed cases increases due to quantitative and qualitative improvements of the screening tests. They resulted in greater efficiency of prenatal diagnosis and, at the same time, in less need for invasive prenatal diagnostic procedures. Another factor is increase in average age at first birth and in the first birth rate for women aged over 35 years resulting in higher overall prevalence rates of Down syndrome, Edwards syndrome, and Patau syndrome in the Czech Republic.

Gradual implementation of first trimester screening in a population with a prior screening strategy: population based cohort study.

OBJECTIVE: To evaluate the implementation of first trimester screening in the Czech Republic during 1996-2007 on the number of infants born with numerical chromosomal anomalies, the gestational age at diagnosis and the number of invasive procedures. DESIGN: A population based cohort study. SETTING: National Registry of Congenital Anomalies, 53 Czech Republic Genetic Departments. POPULATION: About 100,000 pregnancies per year. MAIN OUTCOME MEASURES: Primary outcomes were the rates of fetuses and newborns with diagnosed numerical chromosomal anomalies and the gestational age at diagnosis. Secondary outcomes were the rates of chorion villus sampling (CVS) and amniocenteses and the contribution of age groups on the detection rate of trisomy 21. RESULTS: The number of newborns with Down's syndrome decreased from 5.42/10,000 in 1996 to 3.66/10,000 newborns in the 2007. The total incidence of Down's syndrome increased from 13.42 to 20.66/10,000. The detection rate in women <35 years increased from 35.59 in 1996 to 45.08 in 2007; in women >35 years from 23.73 to 38.52. The number of amniocenteses/detected case of Down's syndrome was 124 in 1996 and 123 in 2007. The corresponding number of CVS decreased dramatically from 83 in 1996 to 10 in 2007. CONCLUSIONS: Despite the increase of maternal age and the corresponding increase of Down's syndrome, the number of newborns with Down's syndrome decreased. Implementation of the first trimester combined screening leads to a shift towards earlier diagnosis of all major chromosomal abnormalities.

Pilot newborn screening project for cystic fibrosis in the Czech Republic: defining role of the delay in its symptomatic diagnosis and influence of ultrasound-based prenatal diagnosis on the incidence of the disease.

The objective need for cystic fibrosis (CF) newborn screening (NBS) in the Czech Republic has recently been substantiated by a significant delay of its symptomatic diagnosis. This trend most likely resulted from the process of decentralisation of health care which led to the deterioration of care for patients who need specialised approaches. Applied newborn screening model (IRT/DNA/IRT) was efficacious enough to detect CF cases with median age at diagnosis of 37 days. The incidence of CF (1 in 6946 live births) ascertained in this project was lower than that established previously by epidemiological studies (1 in 2700-1 in 3300). However, adjustment for broadly applied ultrasound-based prenatal diagnosis (PND) in the 2nd trimester of pregnancy, that was performed within the period of the project (1/2/2005-2/11/2006), rendered an incidence estimate of 1 in 4023. This value is closer to that observed in other CF NBS programmes and reflects influence of PND on the incidence of CF.

Identification of five new families strengthens the link between childhood choroid plexus carcinoma and germline TP53 mutations.

We present five families of paediatric patients suffering from choroid plexus carcinoma in which we found germline TP53 mutations. Only one of the families conformed to the criteria of Li-Fraumeni syndrome and only three (including the Li-Fraumeni syndrome family) met the Chompret criteria for germline TP53 mutation testing. In the remaining two families no family history of cancer was identified and/or the parents of the patient were shown not to carry the mutation. Our results give further support to the notion that the occurrence of this rare paediatric tumour, especially in combination with a positive family history of cancer, but possibly also without any family history, may be an indicator of a germline TP53 mutation. The identification of this genetic defect has important consequences for cancer prevention and treatment in affected families.