LGMD2A
(aka: Calpainopathy) Estimated prevalence: 1 in 100,000 [2] The most common type of limb-girdle muscular dystrophy *Type 2A accounts for over 30% of all LGMD disorders [2] Childhood onset (typically within first two decades of life) [4] Leads to severe motor impairment by early adulthood [4] |
Calpain-3 gene
(capn3) Encodes a muscle-specific, protein-cleaving enzyme >80% chance that CAPN3 deficiency leads to LGMD2A [4] Mutations affect CAPN3 binding to titin (aka connectin), a giant protein essential for the elasticity and renewal of muscle [1] |
References:
[1] Chung, CS, Morton, NE. Discrimination of genetic entities in muscular dystrophy. Am. J.Hum. Genet.
11: 339-359, 1959. [2] Fanin M, Nascimbeni AC, Fulizio L, Angelini C. The frequency of limb girdle muscular dystrophy 2A in northeastern Italy. Neuromuscul. Disord. 2005;15:218–24. [3] Fanin, M et al. Molecular diagnosis in LGMD2A: mutation analysis or protein testing? Hum. Mutat. 24: 52-62, 2004. |
[4] Richard, I et al. Calpainopathy - a survey of mutations and polymorphisms. Am. J. Hum. Genet. 64: 1524-1540, 1999. |