Novel GNB1 Missense Mutation in a Patient with Generalized Dystonia, Hypotonia, and Intellectual Disability
Neurol Genet. 2016 Oct; 2(5): e106. doi: 10.1212/NXG.0000000000000106
Recently, exome sequencing has extended our knowledge of genetic causes of developmental delay through identification of de novo, germline mutations in the guanine nucleotide – binding protein, beta 1 ( GNB1 ) in 13 patients with neurodevelopmental disability and a wide range of additional symptoms and signs including hypotonia in 11 and seizures in 10 of the patients. Limb/arm dystonia was found in 2 patients. Although the finding of 13 carriers of de novo GNB1 mutations among 5,855 individuals is highly unlikely to be a chance finding, independent replication of novel disease genes is important and required for elucidation of the whole phenotypic spectrum, particularly for clinically and genetically highly heterogeneous disorders such as intellectual disability (ID) with currently more than 700 genes implicated in various ID subtypes.