SMN1 and spinal muscular atrophy, type 1: SMA type I (Werdnig-Hoffmann disease) is the most severe form, with symptom onset before 6 months of age.<h4>Patient concerns</h4>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.