Congenital Muscular Dystrophy Type 1A

Abstract

Congenital muscular dystrophy type 1A (MCD1A) represents 30–40% of congenital muscular dystrophies and belongs to a group of disorders with onset at birth or infancy, which are characterized by hypotonia, muscle weakness, and muscle wasting. Respiratory and feeding disorders can also occur. Motor development is delayed and limited (sitting or standing is only possible with help). In few cases the ambulation ability is reached and maintained with orthoses’ help. Infants present with early rigidity of the vertebral column, scoliosis, and respiratory insufficiency. There is facial involvement with a typical elongated myopathic face and ophthalmoplegia. Epileptic attacks are possible, although they occur in less than a third of patients. Intellectual development is normal. MCD1A is caused by mutations in the LAMA2 gene coding for the alpha-2 laminin chain (merosin). Diagnosis is based on muscle biopsy that documents merosin deficiency. MRI reveals diffuse abnormalities in brain white matter, typically sparing the corpus callosum, capsula interna, and cerebellum. CK is increased in the initial phase of the disease. Prenatal diagnosis is possible by chorionic villus sampling for evidence of merosin deficiency and by the identification of mutation in the LAMA2 gene.