Atypical Presentation of Congenital Muscular Dystrophy: A LAMA2 Related Muscular Dystrophy.

The congenital muscular dystrophies are a group of inherited disorders that present in infancy or early childhood with generalized weakness and hypotonia as well as a wide range of other clinical manifestations. Merosin-deficient congenital muscular dystrophy, also referred to as LAMA2-related muscular dystrophy, is caused by biallelic pathogenic variants in the LAMA2 gene and can present with both an early-onset infantile and late-onset childhood form. Patients with the most severe phenotype typically present within the first few months of life with severe weakness and hypotonia and can develop contractures, scoliosis, dysphagia, as well as peripheral nerve and central nervous system abnormalities. We report a case of an infant that presented with focal weakness of his upper extremities that was initially thought to be due to cervical spinal abnormality or brachial plexus injury but was ultimately found to have Merosin-deficient congenital muscular dystrophy. This case highlights an atypical presentation of congenital muscular dystrophy and demonstrates the importance of having a low threshold for testing for congenital muscular dystrophies in infants with abnormalities in strength or tone.