Merosin-deficient muscular dystrophy: pathogenesis, clinical manifestations and therapeutic strategies

Merosin-deficient muscular dystrophy is the most common form of congenital muscular dystrophies (СMD), characterized by genetic heterogeneity and a severe course in most cases. CMD pathogenesis is associated with a partial or complete absence of laminin α2 chains in the basal membrane of muscle fiber caused by a mutation in the LAMA2 gene. The clinical manifestations of LAMA2-associated muscular dystrophy vary from severe СMD (СMD 1A) with an early onset to a relatively mild course with a late onset and phenotype of limb-girdle muscular dystrophy. CMD type 1A is characterized by a delay in motor development from the first months of the life (while the vast majority of children do not master the ability to walk independently), facial muscles weakness, ptosis, ophthalmoplegia, spine rigidity, early occurrence of contractures in the shoulder, elbow, hip and knee joints, restrictive respiratory disorders, nutritional problems, such as disorders of swallowing and chewing, gastroesophageal reflux, low body weight; some children suffer from mental retardation and epilepsy.