Congenital muscular dystrophy due to Integrin alpha7 deficiency.
Incidence
Autosomal recessive. These autosomal recessive diseases affect both sexes equally. This is an exceptionally rare form of congenital muscular dystrophy.
Clinical Characteristics
Primary deficiency of integrin alpha7 appears to be an exceptionally rare form of congenital muscular dystrophy. So far only 3 patients with normal laminin alpha2 but absent integrin alpha7 were found to carry causative mutation in the integrin alpha7 gene. Clinically, these patients rather suffered from a mild congenital myopathy with delayed motor milestones, and muscle biopsies only showed mild variation of fiber size. The most relevant differential diagnosis is with congenital myopathies. This rare disorder has been described in only 3 children who presented with hypotonia in infancy and delayed motor milestones (eg, walked at 2-3 years of age). One patient had mental retardation, and another had contractures and respiratory failure. The condition is due to defects of proteins of the extracellular matrix of peripheral membrane proteins.
Precipitants
None reported.
Provocation Tests
None
Diagnostic Procedures
Serum CK levels are normal or minimally elevated. The direct diagnosis of integrin alpha7 deficiency from immunostaining is hampered by the developmental regulation seen in the first 2 years of life, when integrin alpha7 expression is low.