A rare group of diseases characterized mainly by reduced muscle tone and muscle weakness in the arms, legs and trunk. Symptoms start at birth or soon after.
Reduced muscle tone Muscle weakness Muscular retraction Delayed motor development Brain abnormalities on MRI High creatine kinase levels
lack of merosin (laminin 2) or other defect leading to merosin deficiency
A distinctive diagnostic feature of this type of CMD is found by magnetic resonance imaging (MRI). These brain images show changes in the white matter, which consists of nerve fibers that carry messages from the brain to the spinal cord. Despite the appearance on the MRI, those with merosin-negative CMD have few signs of brain impairment in everyday life.