A novel TUBB3 mutation in a sporadic patient with asymmetric cortical dysplasia

Recent advances in molecular technology have led to the discovery of several genes related to human malformations of cortical development (MCDs). The beta‐tubulin class III gene ( TUBB3 ) was identified as a gene responsible for MCDs. Although mouse‐model experiments have not revealed any findings of neuronal migration disorders, human TUBB3 mutations have been identified in patients with congenital fibrosis of the extraocular muscles. Since the discovery of a TUBB3 mutation, only 15 mutations have been identified. In this study, comprehensive mutation screening through next‐generation sequencing identified a novel TUBB3 mutation (p.Ser230Leu) in a sporadic patient with moderate developmental delay associated with mild MCD. Compared to patients with the alpha‐tubulin class 1a gene ( TUBA1A ) mutations, patients with TUBB3 mutations show milder phenotypic manifestations and milder MCD. Therefore, patients with milder MCD manifestations may be under‐diagnosed, and TUBB3 mutations may be rarely identified. Additional genotype–phenotype information should be accumulated for further understanding of the TUBB3 functional relevance. © 2016 Wiley Periodicals, Inc.