Inherited partial trisomy 8q (22 leads to qter).

We report clinical observations and cytogenetic studies of an inherited form of partial trisomy 8q. Although complete trisomy 8 has in recent years proven to be a clinically recognizable syndrome, partial trisomy 8q has been documented in only six individuals. Of these, five were familial and also partially trisomic for chromosome 22. There has been only one prior report of partial trisomy 8q without partial trisomy 22. Review of these cases provides support for the recent suggestion that the phenotype of trisomy 8 may be caused principally by trisomy of the distal segment of 8q.