Identification of a de novo CACNA1B variant and a start-loss ADRA2B variant in paroxysmal kinesigenic dyskinesia

Paroxysmal kinesigenic dyskinesia (PKD) represents the most prevalent form of paroxysmal dyskinesia, characterized by recurrent and transient attacks of involuntary movements triggered by a sudden voluntary action. In this study, whole-exome sequencing was conducted on a cohort of Chinese patients to identify causal mutations. In one young female case, a de novo CACNA1B variant (NM_000718.3:exon3:c.479C > T:p.S160F) was identified as the causative lesion. This finding may broaden the phenotypic spectrum of CACNA1B mutations and provide a prospective cause of primary PKD. Additionally, a novel start-loss variant (NM_000682.7:c.3G > A) within ADRA2B further denied its association with benign adult familial myoclonic epilepsy, and a KCNQ2 E515D variant that was reported as a genetic susceptibility factor for seizures had no damaging effect in this family. In sum, this study established a correlation between CACNA1B and primary PKD, and found valid evidence that further negates the pathogenic role of ADRA2B in benign adult familial myoclonic epilepsy.