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Limb‐girdle myasthenia with tubular aggregates associated with novel GFPT1 mutations
Author(s) -
Huh SoYoung,
Kim HyangSook,
Jang HoJung,
Park YeongEun,
Kim DaeSeong
Publication year - 2012
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23451
Subject(s) - congenital myasthenic syndrome , medicine , missense mutation , muscle weakness , muscle biopsy , weakness , proximal muscle weakness , endocrinology , mutation , anatomy , biology , genetics , biopsy , gene , acetylcholine receptor , receptor
Limb‐girdle myasthenia with tubular aggregates (LGM with TAs) is a subtype of congenital myasthenic syndrome caused by recessive mutations of glutamine–fructose‐6‐phosphate transaminase 1 ( GFPT1 ). Methods: Clinical and neurophysiological assessment was made in a Korean boy who had proximal limb muscle weakness. Findings suggested a diagnosis of congenital myasthenic syndrome. Results: Muscle biopsy disclosed numerous TAs in muscle fibers, and DNA sequence analysis disclosed 2 novel missense mutations (p.E256Q and p.M499T) in GFPT1 . Treatment with oral cholinesterase inhibitors produced a dramatic improvement in muscle strength. Conclusions: GFPT1 is the key enzyme in the hexosamine biosynthesis pathway, and mutations in GFPT1 cause defective glycosylation in the proteins of the neuromuscular junction. Identification of LGM with TAs among patients with congenital myasthenic syndrome is important because treatment with cholinesterase inhibitors can produce symptomatic improvement. Muscle Nerve 46: 599–602, 2012