PROSPECTIVE-STUDY OF SPINAL MUSCULAR-ATROPHY BEFORE AGE-6 YEARS

Spinal muscular atrophy (SMA) is a common neuromuscular disorder of ch ildhood, associated with a high mortality rate during the first 2 year s of life. Most practitioners expect patients with SMA to follow a pro gressive course with loss of muscle strength and function over 2-10 ye ars. Counselling sessions with parents frequently emphasize the high m ortality rate and risk for respiratory failure. The progressive nature of SMA has been attributed to the loss of motor neurons. Fifty-eight children, ages 6 years and younger, were examined between January, 198 7, and April, 1992, as part of a large, multicenter collaborative stud y of SMA. Muscle function was evaluated at regular intervals using a s tandardized protocol that was demonstrated to be reliable. We determin ed a prevalence of 56% for tongue fasciculations, a prevalence of 22% for facial weakness, and persistent deep tendon reflexes in one patien t. Improved motor function and acquired -milestones during the study w ere documented. This work should contribute toward a better understand ing of the natural history of SMA.