Exome sequencing identifies compound heterozygous KCTD7 mutations in a girl with progressivemyoclonus epilepsy

Abstract

Progressive myoclonic epilepsies (PME) are a clinically and genetically heterogeneous group of rare diseases characterized by myoclonic seizures, tonic-clonic seizures, and neurological deterioration. Here, we genetically analyzed a Chinese patient affected by infantile-onset progressive myoclonic epilepsy. We applied next-generation whole exome capture sequencing with Sanger direct sequencing to the proband and her unaffected parents. Two compound heterozygous mutations were identified in the KCTD7 gene. The first mutation [c. 434A > G(p.Q145R)] was inherited from her father, while the second [c.631C > T(p.R211X)] was inherited from her mother. The two were co-segregated with disease phenotype in the family. To our knowledge, this is the first report of KCTD7 mutations causing PME in the Chinese population, with c. 434A > G in particular being a novel mutation. Our findings supported the important role of KCTD7 in PME and broadened the gene's mutation spectrum. Thus, this study contributes to genetic diagnoses and counselling of families with PME.

Keywords: Compound heterozygous mutations; KCTD7; Progressive myoclonic epilepsies; Whole-exome sequencing.