Better Delineation of CDK13 Related Phenotype and Epigenetic Signature.

The investigators aim to better understand and delineate the genetic syndrome CDK13 This genetic disorder was described in Sepember 2016 in Nature Genetics (PMID 27479907). Since this first publication of 6 individuals carrying the pathogenic mutation CDK13, 37 other individuals carrying a pathogenic mutation of CDK13 have been reported in the litterature The investigators are seeking to better define the phenotype of individuals with pathogenic variants of CDK13, to better understand intellectual functioning as well as the strengths and weaknesses of intellectual functioning by collecting standardized neuropsychological assessments already performed such as WPPSI/WISC and WAIS. For this purpose, The investigators will gather clinical and neuropsychological data already carried out in the context of care. The investigators also aim to gather the cerebral MRI scans already performed in order to better delimit the cerebral anomalies observed in individuals and if the sequence is adapted, The investigators will perform VBM studies. Finally, The investigators will attempt to identify an epigenetic signature in this genetic disease. To this end, The investigators will collect genomic DNA from peripheral blood already collected for genetic analysis and send an anonymized batch of samples to our collaborator, Dr. Bekim Sadicovik. Dr. Bekim Sadicovik and his team will compare the epigenetic DNA methylation-type markers with the corresponding sex and age controls. If specific probes are abnormally methylated in CDK13 individuals, this will determine a disease-specific epigenetic signature. The investigators will then be able to propose an epigenetic signature for individuals with uncharacterized CDK13 variations (class 3, VUS). This method will make it possible to define whether the variation is responsible for the disease or not without going through functional analysis steps that are difficult to implement routinely. The expected benefits are a better understanding of CDK13 disease, keys to neuropsychological rehabilitation, a better understanding of human brain functions, the possibility of proposing an epigenetic signature for people in whom it is not possible to decide whether a variation in the CDK13 gene is pathological or not