A study of a myopathy presenting as idiopathic scoliosis. Multicore disease or mitochondrial myopathy?

Seven cases from a family with a myopathy categorized as "multicore disease" are presented. The clinical picture is unusual because of the predominant progressive involvement of the axial skeletal muscle, with scoliosis and disproportionate respiratory failure as the major clinical features. The propositus and his cousin have both suffered from scoliosis without limb weakness. There is a possibility that this myopathy may be responsible for some cases regarded as idiopathic scoliosis, especially idiopathic infantile scoliosis. The clinical picture is highly variable, and there are sub-clinical cases. The inheritance pattern is consistent with either autosomal dominant, sex-linked recessive or extra-chromosomally inherited disease. Electron microscopy revealed mitochondrial abnormalities, which may have resulted in the Z-disc pathology.