HUMAN MYOPATHY WITH GIANT ABNORMAL MITOCHONDRIA.

The study of children with symmetrical nonprogressive muscle weakness and hypotonia has previously led to the discovery of two new disorders of striated muscle. A third myopathy in a child with hypotonia and proximal weakness is reported. Cytochemical and electron-microscopic studies reveal large, bizarre, interfibrillary and subsarcolemmal mitochondria in muscle obtained by biopsy. Smooth muscle of the vascular wall did not show such abnormalities nor did leucocytes or intramuscular nerves with cytochemical techniques. The basal metabolic rate of the patient was within normal limits.