Spinal muscular atrophy type I in a 3.5-month-old male infant: A case report

Rationale: Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disorder that causes muscle weakness and hypotonia in infants due to survival motor neuron (SMN) protein degeneration. There are 5 recognized main subtypes of SMA, based on the age symptom onset, disease severity, and life expectancy. SMA type I (Werdnig–Hoffmann disease) is the most severe form, with symptom onset before 6 months of age. Patient concerns: We report the case of a 3.5-month-old male infant who presented with complaints of feeding difficulty, weak sucking power, reduced muscle tone, tongue fasciculations, and delayed motor milestones since birth. There was no cognitive or sensory impairment. Diagnoses: Antenatal history revealed polyhydramnios and reduced fetal movements in the third trimester. Electromyography revealed severe motor neuropathy in lower limbs, and multiplex ligation-dependent probe amplification analysis confirmed homozygous deletion of the survival motor neuron 1 gene, establishing the diagnosis of SMA type I. Interventions: The patient was managed with supportive measures, including feeding support via a nasogastric tube, respiratory monitoring, and genetic counseling for the family. Outcomes: Regular follow-up was advised. Disease-modifying therapies were discussed, but were not available due to resource limitations. Lessons: Early recognition and diagnosis of SMA Type I are important to improve survival and clinical outcomes in the patient. Genetic counseling, establishing standardized diagnostic procedures, and ensuring access to new treatments are crucial for optimizing patient care.