Congenital Myopathy

Congenital Myopathy (CM) is a rare group of inherited neuromuscular disorders with early-onset hypotonia and weakness, normal to slightly elevated CK levels, and specific histopathologic characteristics on muscle biopsy. Congenital myopathies were named for histologic abnormalities seen in muscle. Symptoms are often nonprogressive and stable.

https://www.ncbi.nlm.nih.gov/pubmed/24305446