Gait and Movement Disorders
Hyperkinetic movements of the trunk and limbs have been noted in early infancy [1] and jitteriness or tremulousness may be present in the first 6 months of life. Voluntary movements are often irregular, varying from slight jerkiness to uncoordinated coarse movements that prevent walking, feeding, and reaching for objects. Gross motor milestones are delayed; sitting usually occurring after age 12 months and walking often delayed until age 3 to 5 years [2, 3].
In early childhood, the mildly impaired child can have almost normal walking. There may be only mild toe-walking or an apparent prancing gait. This may be accompanied by a tendency to lean or lurch forward. The tendency to lean forward is accentuated during running and, in addition, the arms are held uplifted. For these children, balance and coordination does not appear to be a major problem. More severely affected children can be very stiff and robot-like or extremely shaky and jerky when walking. Although they can crawl fairly effectively, they may "freeze up" or appear to become anxious when placed in the standing position. The legs are kept wide-based and the feet are flat and turned outward. This, accompanied by uplifted arms, flexed elbows and downward turned hands, produces the characteristic gait of AS. Some children are so ataxic and jerky that walking is not possible until they are older and better able to compensate motorically for the jerkiness; about 10% may fail to achieve walking. [4] In situations where AS has not been diagnosed, the nonspecific diagnosis of cerebral palsy is often given to account for the abnormal walking. Physical therapy is helpful in improving ambulation and sometimes bracing or surgical intervention may be needed to properly align the legs.
1. Fryburg JS, Breg WR and Lindgren V. Diagnosis of Angelman syndrome in infants. Am J Med Genet, 1991. 38(1): p. 58-64.
2. Buntinx IM, Hennekam RC, Brouwer OF, et al. Clinical profile of Angelman syndrome at different ages. Am J Med Genet, 1995. 56(2): p. 176-83.
3. Zori RT, Hendrickson J, Woolven S, et al. Angelman syndrome: clinical profile. J Child Neurol, 1992. 7(3): p. 270-80.
4. Clayton-Smith J and Pembrey ME. Angelman syndrome. J Med Genet, 1992. 29(6): p. 412-5.