congenital myopathy 8

A congenital myopathy that is characterized by hypotonia and delayed motor development apparent from infancy or childhood, resulting in difficulties walking or loss of ambulation within the first few decades and that has_material_basis_in heterozygous mutation

A congenital myopathy that is characterized by hypotonia and delayed motor development apparent from infancy or childhood, resulting in difficulties walking or loss of ambulation within the first few decades and that has_material_basis_in heterozygous mutation in the ACTN2 gene on chromosome 1q43. Heterozygous mutation in the ACTN2 gene can also cause distal myopathy-6 (MPD6), which shows later onset and is less severe.

Signs and symptoms

• Internally nucleated skeletal muscle fibers
• Type 1 muscle fiber predominance
• Increased variability in muscle fiber diameter
• Weak extraocular muscles
• Scoliosis
• Delayed ability to walk
• Cardiomegaly
• Reduced vital capacity
• Distal muscle weakness
• Generalized hypotonia