congenital myopathy 9B

A congenital myopathy that is neonatal hypotonia followed by mildly delayed walking in childhood, mainly affecting proximal muscles, and that has_material_basis_in homozygous mutation in the FXR1 gene on chromosome 3q28. Biallelic mutation in the FXR1 gene als

A congenital myopathy that is neonatal hypotonia followed by mildly delayed walking in childhood, mainly affecting proximal muscles, and that has_material_basis_in homozygous mutation in the FXR1 gene on chromosome 3q28. Biallelic mutation in the FXR1 gene also causes CMYP9A.

Signs and symptoms

• Neonatal hypotonia
• Oligohydramnios
• Centrally nucleated skeletal muscle fibers
• Obstructive sleep apnea
• Hypoplastic male external genitalia
• Areflexia
• Fatty replacement of skeletal muscle
• Motor delay
• Decreased fetal movement
• Tongue fasciculations

Also known as: ongenital proximal myopathy 9B with minicore lesions