LAMA2-related dystrophy (LAMA2-RD) results from pathogenic variants in the LAMA2 gene, encoding the α2 subunit of laminin-211 or merosin. The severe phenotype of LAMA2-RD, typically due to complete absence of merosin expression, manifests congenitally with muscle weakness and hypotonia and accounts for 1/3 of congenital muscular dystrophy cases. Establishing disease-relevant biomarkers that can help monitor disease severity and progression beginning in infancy is crucial for clinical trial readiness. While muscle imaging remains a potential biomarker in CMDs, muscle MRI is not ideal given the requirement of sedation in infants and young children and its associated risks. Muscle ultrasound (MUS) offers better sensitivity than MRI in capturing early muscle changes, does not require sedation, and can be performed conveniently at the bedside. However, MUS may reach a ceiling in reflecting fibroadipose muscle replacement relatively early in dystrophic muscle disorders. Here, we present findings from 27 muscle ultrasound studies performed in a cohort of 17 patients with LAMA2-RD (ages 5-71 months; males: 13; females: 4, 186 images total). The mean age at which examined muscle groups reached maximum echogenicity on the modified Heckmatt scale (grade 3, severely increased muscle echogenicity with loss of bone echo) was 34 months of age. Maximum echogenicity was demonstrated as early as 8 months for the hip adductors, hamstrings, and gastrocnemius muscles, while certain proximal muscles of the upper extremities (triceps and deltoid) showed less echogenicity with a persistence of bone echo in the majority of patients through 71 months of age. These results justify further investigation into MUS as a potential imaging biomarker for early LAMA2-RD, particularly for the muscles of the proximal upper extremities. Overall, MUS remains an accessible, non-invasive way to monitor disease progression and may serve as an imaging biomarker to evaluate the efficacy of future therapies in very young patients with LAMA2-RD.