A case of 21q--syndrome with normal SOD-1 activity.

A female infant with del(21)(pter leads to q22.1--2:) constitution identified by G, Q, and R banding is reported. She had marked mental and physical retardation, generalized hypertonia, microphthalmia with persistent hypoplastic primary vitreous, blepharochalasia, high nasal bridge, micrognathia, malformed ears with preauricular pits, and overlying fingers. The assay for superoxide dismutase-1 (SOD-1) activity in the patient revealed a normal value and it was suggested that the gene locus for SOD-1 in 21q22.2 leads to qter is not compatible with the presence of the gene dosage effect in the monosomic state.