Zygodactyly as the most striking physical anomaly in an adult male patient with pure partial trisomy 1q.

We report on a dysmorphic and mentally retarded adult male patient with partial trisomy 1q resulting from a "de novo" tandem duplication of the 1q32.3-->q42 region. The dysmorphic features consisted of facial asymmetry, synophrys, right external strabismus, teeth anomalies and bilateral syndactyly of fingers III-IV and toes II-III evoking zygodactyly. Clinical comparison is made between the present observation and previously reported cases with pure duplication including the chromosome 1 segment (q32-->q42).