Referenced in: none

Automatically associated channels: Kir2.3

Title: A novel GLRA1 mutation associated with an atypical hyperekplexia phenotype.

Authors: Mary L Gregory, Greg F Guzauskas, Terence S Edgar, Kate B Clarkson, Anand K Srivastava, Kenton R Holden

Journal, date & volume: J. Child Neurol., 2008 Dec , 23, 1433-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/19073849

Abstract
Hyperekplexia (MIM #149400) is a rare neurological disorder characterized by an exaggerated startle response, infantile hypertonia and hyperreflexia without spasticity, a hesitant gait that usually improves by 3 years of age, and nocturnal myoclonus. Familial hyperekplexia is usually autosomal dominant resulting from mutations in the inhibitory glycine receptor subunit alpha 1 (GLRA1) gene on chromosome 5q. We identified a 3-generation family with progressively severe phenotypes of hyperekplexia. All affected family members were found to be heterozygous for a novel arginine271proline mutation in GLRA1. Long-term follow-up of the affected members of the third generation, now aged 6 and 7 years, reveals enhanced startle responses and persistent hypertonia of the extremities without clonus or a catch, tight heel cords and abnormal toe-walking gait, and plantar flexor reflexes. The 7-year-old child recently reponded well to a benzodiazepine. Future studies are warranted to examine whether this new missense mutation is solely responsible for this atypical phenotype.