A 2-Year-Old Girl with Hypotonia Since Birth and Delayed Motor and Speech Development

Merosin deficient congenital muscular dystrophy is one of the most common forms of congenital muscular dystrophy. Merosin, also known as laminin α2, is encoded by the LAMA2 gene. It is present in the basal lamina of skeletal muscle and Schwann cells. There is a wide clinical spectrum of the disease with patients usually presenting at birth with hypotonia and weakness accompanied by respiratory and feeding difficulties. Ophthalmoparesis particularly in upper gaze is common. Serum creatine kinase (CK) level can be elevated up to 10 times the normal value. Brain MRI shows increased T2 signal in white matter, which is thought to be from abnormal myelination. Since laminin α2 is present in the basement membranes of Schwann cells, some patients develop peripheral neuropathy. Muscle pathology is characterized by a complete or partial deficiency of laminin-α2 with dystrophic changes.