All are congenital myopathies EXCEPT :
Answer is C (Z band Myopathy) Z band myopathy is not classified as a congenital myopathy. Congenital Myopathy: These are a group of rare disorders distinguished from muscular dystrophies by the presence of specific histochemical and structural abnormalities in muscle. Most of these are characterized by : Onset in early life (primarily disorders of infancy & childhood, but may present in adulthood) Non progressive or slowly progressive course Proximal or generalized muscle weakness Hypotonia Congenital Myopathies: Disease and Inheritance Gene and Locus Clinical Findings Pathologic Findings Central core disease; Ryanodine receptor-1 (RYRI) gene; Early-onset hypotonia and non Cytoplasmic cores are lightly autosomal-dominant 19q 13.1 progressive weakness; associated skeletal deformities; may develop malignant hypehermia eosinophilic and distinct from surrounding sarcoplasm; Found only in type I fibers, which usually predominate, best seen on NADH stain Nemaline myopathy; Autosomal-dominant Weakness, hypotonia and Aggregates of subsarcolemmal autosoma-dominant or (NEM 1) -- Tropomyosin 3 delayed motor development in spindle shaped paicles autosomal-recessive (TPM3) gene; childhood; may also be seen in (nemaline rods); occur Autosomal-recessive (NEM2) -- nebulin (NEB) gene; 2q22 adults; usually ressive. involves nonprog proximal limb muscles most predominantly in type 1 fibers; derived from Z-band material (a-actinin) and best seen on Autosomal-dominant or recessive -- skeletal muscle actin, a chain , severely; skeletal abnormalities may be present modified Gomori stain (ACTA I ) gene; 1q42.1 Myotubular X-linked-myotubularin (MTM 1) X-linked form presents in Abundance of centrally located (centronuclear) gene; Xq28 infancy with prominent nuclei involving the makority of myopathy; X-linked hypotonia and poor prognosis; muscle fibers; central nuclei are (MTM I ), autosomal recessive, or autosomal- autosomal forms have limn weakness and are slowly usually confined to type I fibers, which are small in diameter, but dominant progressive; autosomal recessive form is intermediate in severity and prognosis can occur in both fiber types Other uncommon types include minicore myopathy, fingerprint body myopathy and sarcotubular myopathy.
Centralcore myopathy
Nemaline myopathy
Z band myopathy
Centronuclear myopathy