Familial partial trisomy 8p without dysmorphic features and only mild mental retardation

We report on a mother and her two sons who had a direct duplication of chro-mosome region 8p22-8p23.1 without dys-morphic features and only mild mental retardation. The patients have been stud-ied using G banding, chromosome paint-ing, and FISH using cosmid probes specific for the region 8p23.1-8pter. Com-parison of the phenotypes of our patients and ofpublished patients with an inversion duplication of the short arm of chro-mosome 8 indicates that trisomy for chro-mosome band 8p2l causes the more severe clinical picture in the latter