[Myopathy, cerebellar ataxia and Williams syndrome like features in siblings]

Two female cases, 23- and 21-year-old, of supravalvular aortic stenosis associated with cerebellar hypoplasia, retinitis pigmentosa and myopathy were reported. No family history of mental retardation and cardiovascular anomalies was found. There was no consanguinity between the parents. Pregnancy, labor and delivery were reported to be uncomplicated. When they visited to our hospital at the age of 13 and 11 years, they had short stature, characteristic facial appearance (eg, wide mouth, elongated philtrum, low nasal bridge and broad forehead) and supravalvular aortic stenosis. Neurological examination disclosed mental retardation, retinitis pigmentosa, muscle wasting and contracture of bilateral knee and ankle joints. Gait was unsteady and bradykinetic. Their smooth pursuiting ocular movements were saccadic. No nystagmus was recorded. Mild intention tremor was present. The muscles were slightly hypotonic, but deep tendon reflexes were hyperactive in the lower extremities. The sensory system was normal. Results of chromosome analysis and urine amino acid analysis were normal. The serum creatine kinase was elevated to 1,000-3,000 U. Muscle biopsy revealed nonspecific myopathic changes such as variability of fiber diameter in both fiber types. Neither cell infiltration nor deposits of fat or glycogen was found. Cranial MRIs performed at the age of 22 and 20 years disclosed cerebellar hypoplasia and moderate enlargement of the fourth ventricle. The two cases resembled clinically those of Williams syndrome, but the MRI findings were not consistent with those of the syndrome. The disorder is considered to be either Williams syndrome complicated by some other relatively rare clinical features, or another heredofamilial disease partly resembling Williams syndrome.