A myopathy is a disorder of the muscles that usually results in weakness. Congenital myopathy refers to a group of muscle disorders that appear at birth or in infancy. Typically, an infant with a congenital myopathy will be "floppy," have difficulty breathing or feeding, and will lag behind other babies in meeting normal developmental milestones such as turning over or sitting up.
Muscle weakness can occur for many reasons, including a problem with the muscle, a problem with the nerve that stimulates the muscle, or a problem with the brain. Therefore, to diagnose a congenital myopathy, a neurologist will perform a detailed physical exam as well as tests to determine the cause of weakness. If a myopathy is suspected, possible tests include a blood test for a muscle enzyme called creatine kinase, an electromyogram (EMG) to evaluate the electrical activity of the muscle, a muscle biopsy, and genetic testing.
In muscular dystrophies, the election of the muscle for biopsy is of main importance and the neurologist should in occasions ask for an MRI for this purpose in order to choose a muscle not replaced by fatty tissue. In order to be updated gene table consultation is advisable; an immunohistochemical algorithm as well as Western Blot is proposed. Congenital muscular dystrophy classification is simplified, considering those with no central nervous system involvement and those with white matter changes or abnormal neuronal migration. In some limb girdle dystrophies.