Quadriceps myopathy: Forme fruste of Becker muscular dystrophy

Abstract

We examined dystrophin, the protein product of the Duchenne muscular dystrophy gene, in muscle biopsy specimens from 4 male patients with quadriceps myopathy, all of whom showed a mild and slowly progressive myopathy confined to the quadriceps muscles. All 4 patients had clear abnormalities of dystrophin, and were diagnosed as having Becker muscular dystrophy by both immunofluorescence and immunoblot examinations; that is, dystrophin of an abnormal molecular mass was visualized in muscle cryosections as "patchy" or discontinuous immunostaining at the surface membrane of the muscle fibers. One patient had a brother who showed widespread myopathic changes consistent with typical Becker muscular dystrophy. We conclude that the syndrome called quadriceps myopathy includes a group of forme fruste Becker muscular dystrophy.

Quadriceps myopathy caused by skeletal muscle-specific ablation of βcyto-actin

“…Quadriceps myopathy (QM) is a rare muscle disease predominately affecting the quadriceps muscles with clinical symptoms arising in adulthood (Sunohara et al, 1990). There is considerable heterogeneity in QM because etiologies can range from a form of limb-girdle muscular dystrophy (Swash and Heathfield, 1983) to polymyositis (Mohr and Knowlson, 1977;Turner and Heathfield, 1961).…”

“…Genetic variants of QM are suspected to arise from autosomal dominant (Charniot et al, 2006;Espir and Matthews, 1973), autosomal recessive (Jarry et al, 2007;Mahjneh et al, 2003), and X-linked recessive (Kumari et al, 2000;Wada et al, 1990) inheritance patterns, indicating that several gene products probably play a role in QM pathology. However, multiple reports of alterations in the dystrophin gene, the gene mutated in males afflicted with Duchenne muscular dystrophy (Hoffman et al, 1987), resulted in a QM diagnosis (Beggs et al, 1991;Kumari et al, 2000;Sunohara et al, 1990;Wada et al, 1990).…”

Clinical Utility Gene Card for: Becker muscular dystrophy

“…The difference in phenotype is usually dependent on whether the variant is in frame, resulting in an internally deleted, shorter, yet partially functional dystrophin protein (BMD), or out-offrame resulting in no dystrophin protein (DMD) [1]. However, other clinical phenotypes may arise from a DMD variant such as isolated quadriceps myopathy [2]; asymptomatic hyperCKemia [3]; myalgia, cramps and rhabdomyolysis [4]; dilated cardiomyopathy [5]; isolated cognitive impairment [6]; and symptomatic female carriers [7].…”

Autosomal dominant Late-onset Quadriceps Myopathy: Three Patients of a Taiwanese Kindred

“…A number of disease entities, hereditary and sporadic, neurogenic and myopathic, have been associated with this syndrome. They include myositis (2-4), inclusion body myositis (IBM) (5,6), Becker muscular dystrophy (BMD) (7)(8)(9), Ehlers-Danlos syndrome (10), proximal myotonic myopathy (PROMM) (11), Lewis-Sumner syndrome (12), lamin A/C gene mutation (13,14), diabetic amyotrophy (15), and neurogenic quadriceps amyotrophy (16)(17)(18). Therefore, selective quadriceps weakness/atrophy is considered to be a syndrome rather than a disease entity.…”