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.