**5. Prognosis**

The course of SMA is relentlessly progressive. Prognosis varies according to the age of onset, type of SMA, and the maximum function achieved. The age at the time of the onset has the strongest relationship to prognosis. It appears that the earlier the onset of the disease, the faster the progression and the poorer the prognosis. The current prognosis for children with type I SMA is very poor, with the death usually occurs in the first two years of life as a result of respiratory failure caused by respiratory complications. Some children with SMA type I can survive beyond two years of age with the use of ventilator assistance.1 The prognosis of type II SMA is extremely variable. Patients with type II SMA have short life span; survival into adulthood is possible with aggressive respiratory care. Majority of patients with type III SMA remain independent in ambulation throughout adult life. Patients with Type III SMA are expected to have normal life expectancy. Patients with the onset begins before two years of age continue to ambulate until an average of twelve years of age. Patients with the onset after two years of age continue to ambulate throughout the adult life.25
