Limb Girdle Muscular Dystrophy Type 2G

Synonyms

Telethoninopathy

Definition and Characteristics

Autosomal recessive, relatively mild form of progressive neuromuscular disorder with a wide spectrum of inter- and intra-familial clinical variability. The age at onset ranges from 9 to 15 years old and loss of ambulation occurs during the third or fourth decade in about 30% of the patients. Clinical features include proximal involvement and marked weakness and/or atrophy in the distal muscles of the legs. Asymmetric calf hypertrophy is a common sign. Heart involvement is not rare. Serum CK is 3-fold to 30-fold increased. Muscle biopsy shows a dystrophic pattern, including rimmed vacuoles.

Prevalence

Described first in five unrelated Brazilian families [1] and confirmed in three additional Brazilian families in 2005 [2]. Represents about 1–2% of the AR-LGMD forms. The prevalence of LGMDs ranges from 1 in 14,000 to 1 in 20,000.

Genes

T-CAP, mapped at 17q11–12. One prevalent pathogenic change was identified in seven families in a...