Human chromosome polymorphism and congenital malformations.

Several authors have suggested that heterochromatin polymorphism influences the origin and/or development of different malformations. In this investigation special consideration was given to the A1qh + variant. Several families with this variant are reported in which the incidence of otherwise rare malformations is surprisingly high. The possibility that the A1qh+ varient or, more probably, interactions between all types of heterochromatin polymorphism are of pathogenetic significance is considered.