Novel variants in TBC1D24 associated with epilepsy and deafness: Report of two cases

Purpose: To identify the causative variants in two unrelated Chinese patients presenting with epilepsy and deafness. Methods: The two patients underwent a thorough examination, including brain MRI, EEG and metabolic studies. Next-generation sequencing (NGS) was performed on genomic DNA samples from the siblings and parents. Sanger sequencing was used to confirm the variants. Results: Gene sequencing revealed that they carried two novel compound heterozygous missense variants of the TBC1D24: c.116 C > T (p.Ala39Val) and c.827 T > C (p.Ile276Thr) in patient 1; c.404 C > T (p.Pro135Leu) and c.679 T > C (p.Arg227Trp) in patient 2. Audiologic examination showed bilateral sensorineural hearing loss in both patients. Conclusion: We have found novel variants in the TBC1D24 in two Chinese unrelated patients. They result in a rare phenotype, characterized by drug-resistant epilepsy and deafness.