The purpose is to determine the benefit of next generation sequencing (NGS) targeted on genes
involved in intellectual disability for etiologic diagnosis of intellectual disabilities. In
other words, it concerns the number of patients whose etiologic diagnosis will be established
with NGS and could not with common techniques. Actually, the molecular etiology of
intellectual disability is crucial to calculate the risk of recurrence and allows the
perinatal diagnosis to these families.
Secondary purposes are:
1. To determine the place of NGS in the strategy of etiologic diagnosis of intellectual
disability, to determine the order of analyses performed for a patient with intellectual
disability without clinical signs.
2. To evaluate the number of variants with unknown significance and thus non-usable for
genetic counselling without supplementary analysis.
3. To determine the number of samples that can be at most pooled keeping a good efficacy of
capture and results with suitable read depth
4. To determine the possibility of detecting copy number variations (CNVs) in genes of
interest with NGS
5. To establish genotype/phenotype correlations for each gene for which a mutation has been
6. To optimize the software pipelining for a rapid analysis for diagnosis.