Context and Objective: Considering the lack of accurate and up-to-date information available about neural tube defects (NTDs) in France, the purpose of this study was to review clinical and epidemiological data of NTDs and to evaluate the current efficiency of prenatal diagnosis in Alsace (northeastern France). Methods: A population-based retrospective study was performed from data of the Registry of Congenital Malformations of Alsace between 1995 and 2009. Data were analyzed as a whole and according to the anatomical type of the malformation (anencephaly, cephalocele and spina bifida). Statistical analyses were carried out using the Statistical Package for the Social Sciences. Results: 272 NTDs were recorded divided in 113 cases of anencephaly (42%), 35 cases of cephalocele (13%) and 124 cases of spina bifida (45%). The total prevalence at birth of 14/10,000 (95% CI 13-16) was stable throughout the reporting period. A chromosome abnormality was identified in 27 cases (12% of all karyotyped cases). NTDs were prenatally diagnosed by ultrasound in 88% of the cases. The mean age upon prenatal diagnosis slightly declined during the 15-year period, significantly for spina bifida only. The global rate of terminations of pregnancy following prenatal diagnosis was 97% (230/238). Conclusion: This work constitutes a unique population-based study providing accurate and specific up-to-date data from a unique center over a longer period (1995-2009). The most important information concerns the high and stable prevalence, which calls into question the efficiency of the primary prevention by folic acid supplementation and the efficiency of prenatal diagnosis.

High-throughput sequencing (HTS) of human genome coding regions allows the simultaneous screen of a large number of genes, significantly improving the diagnosis of non-syndromic intellectual disabilities (ID). HTS studies permit the redefinition of the phenotypical spectrum of known disease-causing genes, escaping the clinical inclusion bias of gene-by-gene Sanger sequencing. We studied a cohort of 903 patients with ID not reminiscent of a well-known syndrome, using an ID-targeted HTS of several hundred genes and found de novo heterozygous variants in TCF4 (transcription factor 4) in eight novel patients. Piecing together the patients from this study and those from previous large-scale unbiased HTS studies, we estimated the rate of individuals with ID carrying a disease-causing TCF4 mutation to 0.7%. So far, TCF4 molecular abnormalities were known to cause a syndromic form of ID, Pitt-Hopkins syndrome (PTHS), which combines severe ID, developmental delay, absence of speech, behavioral and ventilation disorders, and a distinctive facial gestalt. Therefore, we reevaluated ten patients carrying a pathogenic or likely pathogenic variant in TCF4 (eight patients included in this study and two from our previous ID-HTS study) for PTHS criteria defined by Whalen and Marangi. A posteriori, five patients had a score highly evocative of PTHS, three were possibly consistent with this diagnosis, and two had a score below the defined PTHS threshold. In conclusion, these results highlight TCF4 as a frequent cause of moderate to profound ID and broaden the clinical spectrum associated to TCF4 mutations to nonspecific ID.

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