Vacuolar myopathy sparing the quadriceps

Abstract

Twenty-two Jewish patients, belonging to 15 families, 11 of them from Iran and three possibly of Iranian stock, suffered from progressive muscle weakness and wasting. The initial symptom was usually distal leg muscle weakness, appearing in the third or fourth decade and insidiously involving the proximal muscles and to a lesser extent the upper limbs. The quadriceps muscle was consistently spared even in advanced cases. Computerized tomography (CT) scans of muscles demonstrated variable wasting and fatty replacement of limb and axial muscles, while the vastus lateralis muscle retained its normal CT appearance. The typical light microscopy features of the affected muscles were: presence of vacuoles within muscle fibres, internal nuclei, longitudinal fibre splitting and, in severely affected muscles, endomysial fibrosis without, inflammation or fibre necrosis. Electron microscopy suggested that the vacuoles were autophagic. Cytoplasmic and intranuclear inclusions were rare. While electromyography (EMG) revealed presence of spontaneous activity, however, analysis of muscle action potentials, turns-amplitude ratio, macro-EMG and single fibre EMG suggested a primary myopathic disorder. Consanguinity in seven families, the parents being first cousins, and the presence of additional affected siblings of both sexes may suggest an autosomal recessive trait. The presence of this disorder in Iranian Jews may indicate that this is a distinct myopathic entity.

Familial mixed congenital myopathy with rigid spine phenotype

“…Cytoplasmic bodies may be observed in inclusion body myositis and may occur in familial inclusion body myopathy. 22 Finally, the combination of vacuoles and filamentous inclusions has been reported by others in patients who also presented with RSS.…”

Establishment of the genomic structure and identification of thirteen single-nucleotide polymorphisms in the human RECK gene

“…As part of a positional cloning strategy towards identifying the gene associated with hereditary inclusion body myopathy (IBM2), a rare neuromuscular disorder characterized by adultonset, slowly progressive distal and proximal weakness and typical muscle pathology (Sadeh et al, 1993), we generated a 1-Mb physical and transcriptional map of the disease region, on chromosome 9p13 → p12 (Eisenberg et al, 2001). Based on the location of the RECK gene within this map and its expression in a wide variety of human tissues including muscle fibers (Takahashi et al, 1998) we considered RECK as a candidate gene for IBM2.…”

Genetics of GNE myopathy in the non-Jewish Persian population

“…Notably, the quadriceps, for unknown reasons, is selectively spared, despite marked weakness of all other hip muscles. 2 Upper limbs, especially the scapular and proximal muscles, are usually involved in the advanced stages. 1 Typically, the initial disease manifestation is foot drop and the consequent altered gait resulting from the involvement of the foot dorsiflexion muscles.…”