Severe symmetric flaccid paralysis: unable to sit unsupported
Upper cranial nerves spared: alert expression and normal eye movements
Weakness of the bulbar muscles: weak cry, poor suck and swallow reflexes, pooling of secretions, aspiration, and fasciculations of the tongue
Respiratory failure: intercostal muscles typically more affected than the diaphragm, resulting in paradoxical breathing (inspiratory efforts cause the rib cage to move inward and the abdomen to move outward) and the development of a characteristic bell-shaped chest deformity<unk>  2 (intermediate form) and<unk>  3 (mild form; Kugelberg-Welander disease) have a later onset and a less severe course.<unk>  2 presents between 3 and 15 months of age, whereas<unk>  3, the least severe, typically presents with signs of weakness at or after one year of age and progresses to a chronic course. Adult onset of<unk>  (type 4) usually presents in the second or third decade of life and is otherwise similar to<unk>  type 3.
Spinal muscular atrophy
THE MISFITS [1]
Amyotrophic lateral sclerosis
Trauma
Lambert-Eaton myasthenic syndrome
Heart
Cerebral palsy
Congenital heart disease