A novel FKRP gene mutation in a Taiwanese patient with limb-girdle muscular dystrophy 2I

Abstract

Limb-girdle muscular dystrophy (LGMD) is a group of hereditary muscle diseases with preferential involvement of the shoulder and pelvic girdle muscles, but with no pathognomonic features as in facioscapulohumeral and congenital muscular dystrophies. We report 18-year-old female with progressive shoulder and pelvic muscle weakness. She had marked restrictive pulmonary dysfunction. Echocardiogram showed mild decrease in ejection fraction of 52% (normal: >55%). She was first seen in our hospital at age 2 years with progressive proximal muscle weakness and elevated creatine kinase (CK) level to 15,290 IU/L, with what clinically and pathologically appeared to be steroid-responsive inflammatory myopathy. She responded dramatically to steroid therapy. Progressive proximal muscle weakness began again at age 8 years. Serum CK was 14,910 IU/L. She was wheelchair-bound by age 12. Muscle biopsy showed dystrophic changes without inflammation with reduced immunoreactivity to an antibody against sugar chain (VIA4-1) of α-dystroglycan. On laminin overlay assay, there was a nearly complete loss of laminin-binding activity to α-dystroglycan. Genetic analysis of fukutin-related protein ( FKRP) gene revealed a novel compound heterozygous mutation of c.823C > T (p.R275C) and c.948delC, confirming the diagnosis of LGMD2I, the first reported case in East Asia.