SVIL

Autosomal recessive inheritance

Myofibrillar myopathy-10 (MFM10) is an autosomal recessive structural muscle disorder characterized by onset of muscle pain, cramping, and exercise fatigue in the first or second decades of life. Some patients have mild contractures of the large joints apparent in early childhood. Affected individuals have a characteristic appearance of a thick neck and prominent shoulder girdle with anteverted shoulders and a tendency toward kyphosis. There is no apparent muscle weakness, but some affected individuals show progressive muscle rigidity leading to limited mobility. There is variable cardiac involvement, ranging from chest pain with left ventricular hypertrophy to subclinical signs such as abnormal EKG or elevated cardiac enzymes.

Definition: A myofibrillar myopathy characterized by onset of muscle pain, cramping, and exercise fatigue in the first or second decades of life that has material basis in homozygous or compound heterozygous mutation in SVIL on chromosome 10p11.23.