Here we report on 4 unrelated patients with reciprocal translocations which resulted in duplication of the distal portion of chromosome 1q. Although the patients had certain non-specific malformations in common, our investigation and a review of the literature do not suggest the existence of a distinct phenotype due to this chromosome abnormality. We think that the coexisting deletion present in each of these patients is responsible for most of the observed differences in clinical manifestations. The variable phenotype makes clinical recognition difficult and precludes making a long-term prognosis.