Episodic and Electrical Nervous System Disorders Caused by Nonchannel Genes
ANNUAL REVIEW OF PHYSIOLOGY, VOL 77
Authors: Lee, Hsien-yang; Fu, Ying-Hui; Ptacek, Louis J.
Abstract
As noted in the separate introduction to this special topic section, episodic and electrical disorders can appear quite different clinically and yet share many overlapping features, including attack precipitants, therapeutic responses, natural history, and the types of genes that cause many of the genetic forms (i.e., ion channel genes). Thus, as we mapped and attempted to clone genes causing other episodic disorders, ion channels were always outstanding candidates when they mapped to the critical region of linkage in such a family. However, some of these disorders do not result from mutations in channels. This realization has opened up large and exciting new areas for the pathogenesis of these disorders. In some cases, the mutations occur in genes of unknown function or without understanding of molecular pathogenesis. Recently, emerging insights into a fascinating group of episodic movement disorders, the paroxysmal dyskinesias, and study of the causative genes and proteins are leading to the emerging concept of episodic electric disorders resulting from synaptic dysfunction. Much work remains to be done, but the field is evolving rapidly. As it does, we have come to realize that the molecular pathogenesis of electrical and episodic disorders is more complex than a scenario in which such disorders are simply due to mutations in the primary determinants of membrane excitability (channels).
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.