Extramuscular manifestations in children with severe congenital myopathy due to ACTA1 gene mutations.

We examined three patients with a severe infantile type of congenital myopathy due to dominant, missense ACTA1 mutations. In addition to muscle weakness, all three patients showed developmental delay in word comprehension during early childhood. All also showed frontal lobe hypoplasia and lateral ventricular dilatation.

Post-streptococcal chorea in an adult with bilateral striatal encephalitis.

We present distinctive MRI findings in an adult female patient with possible Sydenham's chorea. T2-weighted MRI showed bilaterally symmetric, diffusely homogenous, and clearly demarcated hyperintensities selectively involving the entire striatum with swelling of the bilateral caudate heads. The MRI features may reflect the pathogenetic mechanisms of Sydenham's chorea associated with a specific autoimmune response to the basal ganglia.

Congenital myotonic dystrophy can show congenital fiber type disproportion pathology.

Congenital myotonic dystrophy (CDM) is associated with markedly expanded CTG repeats in DMPK. The presence of numerous immature fibers with peripheral halo is a characteristic feature of CDM muscles together with hypotrophy of type 1 fibers. Smaller type 1 fibers with no structural abnormality are a definitive criterion of congenital fiber type disproportion (CFTD).

Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.

Caveolae are invaginations of the plasma membrane involved in many cellular processes, including clathrin-independent endocytosis, cholesterol transport, and signal transduction. They are characterized by the presence of caveolin proteins. Mutations that cause deficiency in caveolin-3, which is expressed exclusively in skeletal and cardiac muscle, have been linked to muscular dystrophy.