Dysferlinopathy
Overview
Dysferlinopathy (medical condition): An autosomal recessive form of limb-girdle muscular dystrophy where muscle weakness and atrophy is caused by deficiency of the dysferlin protein. There is variation in the degree of muscle involvement and the rate of progression.
Symptoms
Some of the symptoms of Dysferlinopathy incude: * Lower limb muscle weakness * Lower limb muscle wasting * Wasting of proximal deltoid muscle * Weakness of proximal deltoid muscle * Hypertrophy of distal deltoid muscle
Diagnosis
Dysferlinopathy caused by mutations in the DYSF gene includes a spectrum of muscle disease characterized mainly by two phenotypes: Miyoshi myopathy with primarily distal weakness and limb-girdle muscular dystrophy type 2B (LGMD2B) with primarily proximal weakness. Miyoshi myopathy. Miyoshi myopathy is a distal myopathy characterized by the following [Miyoshi et al 1986]: * Mid- to late-childhood or early-adult onset; mean age at onset: 19.0 years [Aoki et al 2001] * Early and predominant involvement of the calf muscles * Slow progression * Elevation of serum CK concentration, often ten to 100 times normal; mean CK: 8,940 IU/L [Aoki et al 2001] * Primarily myogenic pattern on EMG * Biopsy evidence of a chronic, active myopathy without rimmed vacuoles LGMD2B. LGMD2B is characterized by the following: * Predominant weakness and atrophy of muscles of the pelvic and shoulder girdle * Onset in the proximal lower limb musculature in the late teens or later * Massive elevation of serum CK concentration * Slow progression * Subclinical involvement of distal muscles, identified by careful examination or ancillary investigations such as muscle CT scan, in some individuals