Absence of γ-sarcoglycan (35 DAG) in autosomal recessive muscular dystrophy linked to chromosome 13q12

We have partially sequenced rabbit skeletal muscle γ-sarcoglycan an integral component of the dystrophin-glycoprotein complex. Specific antibodies were produced against a γ-sarcoglycan peptide and used to examine the expression of γ-sarcoglycan in skeletal muscle of patients with severe childhood autosomal muscular dystrophy linked to chromosome 13q12 (SCARMD). We show by immunofluorescence and Western blotting that in skeletal muscle from these patients γ-sarcoglycan is completely absent and α- and β-sarcoglycan are greatly reduced in abundance, whereas other components of the DGC are preserved. In addition, ne show that in normal muscle α-, β-, and γ-sarcoglycan constitute a tightly associated sarcolemma complex which can not be disrupted by SDS treatment.