A malformed male infant with pure partial trisomy 12q (q24.1 leads to qter), resulting from an unbalanced segregation of a paternal balanced translocation t(2;12)(q37;q24.1), is described. The cytogenetic and clinical abnormalities of the proband are compared with those of four previously reported cases of partial trisomy 12q, two of which also appear to have pure trisomy of segment 12q24.1 leads to 12 qter.