congenital myopathy 20

A congenital myopathy that has_material_basis_in homozygous or compound heterozygous mutation in the RYR3 gene on chromosome 15q13 and that shows wide phenotypic variability. Some patients present in early childhood with proximal muscle weakness affecting the

A congenital myopathy that has_material_basis_in homozygous or compound heterozygous mutation in the RYR3 gene on chromosome 15q13 and that shows wide phenotypic variability. Some patients present in early childhood with proximal muscle weakness affecting the lower and upper limbs resulting in difficulties running and climbing, whereas others present soon after birth with congenital limb or distal contractures.

Signs and symptoms

• Difficulty climbing stairs
• Scapular winging
• Gowers sign
• Weakness of facial musculature
• Difficulty running
• Type 1 muscle fiber predominance
• Proximal muscle weakness
• Narrow face
• Centrally nucleated skeletal muscle fibers
• Micrognathia