P.1.20 GOSR2: A novel form of Congenital Muscular Dystrophy

• Published in: Neuromuscular disorders : NMD Vol. 23; no. 9; p. 748
• Main Authors: Tsai, L, Schwake, M, Corbett, M.A, Gecz, J, Berkovic, S, Shieh, P.B
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2013
• Subjects: Neurology
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2013.06.404

We describe an 36 week male who was born with mild hypotonia and subsequently found to have severe developmental delay. There is also reported optic nerve atrophy. Serum creatine kinase (CK) was 5582. MRI of the brain demonstrated periventricular white matter loss, ventriculomegaly, and a thin corpus callosum. His muscle biopsy demonstrated severe non-specific dystrophic changes. Staining with VIA4-1, however, demonstrated normal levels of glycosylated alpha-dystroglycan, and genetic testing for genes known to cause Walker-Warburg Syndrome (WWS) was negative. Whole exome sequencing was performed, which demonstrated compound heterozygous mutations in GOSR2 , including a previously described mutation c.430G > T as well as a novel splice site mutation c.336 + 1G > A. Previous reports have described homozygous c.430G > T mutations as causative of progressive myoclonus epilepsy (PME), a syndrome characterized by myoclonus, seizures, and progressive cognitive decline. Patients with this GOSR2 mutation also have areflexia, tremors, ataxia, and mildly elevated CK levels, suggesting a possible subclinical myopathy. Muscle biopsies on these PME patients, however, have been normal. Interestingly, at 28 months of age, the patient began to experience clinical seizures with one episode of status epilepticus. GOSR2 encodes for a SNARE involved with protein transport from the endoplasmic reticulum to the trans -Golgi apparatus. Our studies suggest that GOSR2 may play a role in the transport of critical membrane glycoprotein complexes of myocytes.