Cerebral palsy masking spinal muscular atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive anterior horn cell disease that results in progressive muscular weakness and atrophy without sensory involvement. A wide clinical spectrum that ranges from early death to essentially normal adult live exists. We describe a case of two 12 years olds, who represent two of three surviving non-identical quadruplets, born at 25 weeks gestational age. A diagnosis of hypotonic cerebral palsy (CP) was made in early childhood and early intervention services were initiated. At 3 years of age, MRI's showed white matter changes. Both briefly attained Gross Motor Functional Classification Scale (GMFCS) 3 status, but by 12 years of age their ambulatory abilities had decreased to Level 4. Physical Medicine and Rehabilitation (PM&R) physicians were consulted. On exam, distal lower extremities atrophy, hypotonia, hyporeflexia, and muscle weakness were noted. Neither child had upper motor neuron signs or spasticity. Cognition was normal. Neuromuscular disorder was suspected and genetic testing confirmed spinal muscular atrophy in both patients. While prior MRI/CT demonstrated static encephalopathy, recognition of symptoms and signs consistent with neuromuscular disease should have led to a secondary diagnosis. Therapeutic and surgical treatment decisions may have differed. Fragmentation of care and lack of a comprehensive team approach also contributed to the delay in recognition of their dual diagnosis.