It has a heterogeneous disease spectrum ranging from a severe, early-onset congenital muscular dystrophy (complete Laminin subunit α2 deficiency, also called merosin-deficient congenital muscular dystrophy type 1A (MDC1A)) to a mild, childhood- or adult-onset limb-girdle type muscular dystrophy (partial Laminin subunit α2 deficiency). The gene discussed is LAMA2; the disease is hyperinsulinemic hypoglycemia, familial, 4.