Novel loss-of-function PRRT2 mutation causes paroxysmal kinesigenic dyskinesia in a Han Chinese family
BMC NEUROLOGY
Authors: Ji, Zhisong; Su, Quanxi; Hu, Lingling; Yang, Qi; Liu, Cuixian; Xiong, Jun; Xiong, Fu
Abstract
Background: Mutations in proline-rich transmembrane protein 2 (PRRT2) are a cause of paroxysmal kinesigenic dyskinesia (PKD). In this study, we investigated the PRRT2 gene mutation in a Chinese Han family with PKD and study the pathogenesis of the mutation with PRRT2 gene. Methods: Peripheral venous blood was taken from the family members. Sanger sequencing was used for novel mutation sequencing. For the pathogenesis with the novel mutation was analyzed by bioinformatics, real-time PCR, subcellular localization and Western blot. Results: The Sanger sequencing showed a novel mutation, c.186-187delGC, a deletion mutation, in exon 2 of the PRRT2 gene, the frameshift mutation generated a truncated protein that was stably expressed in transfected Human embryonic kidney (HEK) 293 cells. A subcellular localization assay in COS-7 cells with GFP-tagged protein showed nuclear localization for the mutant protein while the wild-type protein was localized in membranes. Co-transfection of HEK293 cells with wild-type and mutant expression plasmids cells did not influence mRNA or protein expression from the wild-type plasmid. Conclusions: Our findings demonstrated that the c.186-187delGC mutation resulted in a truncated protein from the PRRT2 gene to involve in PKD pathogenesis with haploinsufficiency. The results extend the mutation spectrum of the PRRT2 gene and provide a new example for studying the pathogenesis of the mutated PRRT2 gene.
Familial hemiplegic migraine with a PRRT2 mutation: Phenotypic variations and carbamazepine efficacy
BRAIN & DEVELOPMENT
Authors: Suzuki-Muromoto, Sato; Kosaki, Rika; Kosaki, Kenjiro; Kubota, Masaya
Abstract
Objective: To understand the clinical characteristics of familial hemiplegic migraine (FHM) caused by a PRRT2 mutation and to examine the efficacy of preventive treatment. Methods: Using the literature, we investigated clinical details of FHM in 3 generations of patients with a PRRT2 mutation and compared them with those in 17 patients with the same mutation from 6 families. Results: In most of the affected patients, the onset was observed during the teen years. Complicated phenotypes tended to be shared in each family, and five patients showed spontaneous remission. With regard to treatment, low-dose carbamazepine (CBZ) was effective in three patients. Conclusion: Considering the clinical features, we suggest that low-dose CBZ is efficacious for FHM treatment in patients with a PRRT2 mutation. The treatment duration should be carefully considered because some patients show spontaneous remission. More accumulated data from familial cases might help elucidate PRRT2 function and establish standard treatment for FHM. (C) 2019 Published by Elsevier B.V. on behalf of The Japanese Society of Child Neurology.