Inverted tandem duplication of the short arm of chromosome 8: a non-random de novo structural aberration in man. Localization of the gene for glutathione reductase in subband 8p21.1.

Two patients with an inverted duplication of bands 8p21-p23 are described. The gene for glutathione reductase (GSR; E.C.1.6.4.2) has previously been localized to band 8p21. In one of the patients subband 8p21.1 was included in the duplication; GSR activity in the red blood cells was increased. In the other patient, subband 8p21.1 was not included in the duplication and GSR activity was normal. This allows GSR to be assigned to subband 8p21.1. Including the present 2 patients, at least 13 cases of this abnormality have been published. We have obtained data on at least 8 further cases (unpublished). We conclude that inv dup (8p) is a non-randomly occurring de novo structural aberration in man. The GSR results in our cases prove that breakpoints can be different in different patients. Clinical symptoms and signs include some common features but show marked interpatient variation which should, at least in part, be caused by the differences in break-points. A detailed collaborative study to determine the clinical and epidemiological features of this entity is recommended.