Targeted gene under study:
SCN1A OMIM #182389; SCN2A OMIM #182390
Developmental Epileptic Encephalopathy
Developmental Delay & Intellectual disability
Motor Delay
Epilepsy
Abstract
During a genotype-first analysis of the voltage-gated sodium ion channels we found a homozygous case of SCN1A in a three siblings with progressive encephalopathy and epilepsy and in SCN2A a case with two siblings with intellectual disability. In both cases family segregation confirmed the heterozygous form in the parents and healthy siblings.
SCN1A & SCN2A are associated with developmental epileptic encephalopathy as well as neurodevelopmental and motor delay (OMIM # 182389, OMIM #182390). These cases are usually autosomal dominant.
In both our cases they are Autosomal Recessive, but finding such unique cases has occurred before in SCN1A.
We are looking for more cases of biallelic SCN1A and SCN2A variants with a developmental delay phenotype to expand on this finding.
Coordinating team
Nathan Routledge – nathan.routledge.22@ucl.ac.uk
Institution
Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
Specific requirements beyond clinical data and genotype data sharing:
1- Re-analysis of DNA samples: No
2- Resampling of patients: No
3- Linked to a translational/basic research project: Yes