Definition:

The congenital myopathies are a group of genetic muscle disorders characterised clinically by hypotonia and weakness, usually from birth, and a static or slowly progressive clinical course. Congenital myopathies are mainly defined by the predominant histopathological features which include nemaline rods, central cores, multiple minicores, central nuclei, and selective hypotrophy of type 1 fibres. Based on these features, individual congenital myopathies such as nemaline myopathy, central core disease, multi-minicore disease, centronuclear myopathy, and congenital fiber type disproportion were reported. Over the past decade there have been major advances in defining the genetic basis of the majority of congenital myopathy subtypes. However the relationship between each congenital myopathy, defined on histological grounds, and the genetic cause is complex. Many of the congenital myopathies are due to mutations in more than one gene, and mutations in the same gene can cause different muscle pathologies.