A 7-month-old male child with a de novo, seemingly balanced reciprocal 5p/16q translocation and karyotype 46,XY,t(5;16) (p14;q21), resulting from a maternal meiotic error, is described. The clinical findings in this patient are strikingly similar to those in the only patient with partial deletion 16q hitherto described, [del(16)(q21)], indicating that during the 5p/16q rearrangement, 16q material was lost and suggesting that partial or total deletion of the long arm of chromosome 16 distal to band q21 is accompanied by a distinct clinical phenotype.