PREAXIAL ACROFACIAL DYSOSTOSIS (NAGER SYNDROME) ASSOCIATED WITH AN INHERITED AND APPARENTLY BALANCED X-9 TRANSLOCATION - PRENATAL AND POSTNATAL LATE REPLICATION STUDIES

We report on an infant with preaxial acrofacial dysostosis (Nager synd rome) who was diagnosed prenatally as having an apparently balanced X/ autosome translocation [46,X,t(X;9)(p22.1;q32)mat] inherited from a pr eviously diagnosed mosaic translocation carrier mother [46,XX/46,X,t(X ;9)(p22.1;q32)]. Replication studies on amniocytes showed the normal X chromosome to be late replicating while the same studies repeated on the infant's lymphocytes showed the translocated X chromosome to be la te replicating in most cells. Late replication studies of the mother's lymphocytes demonstrated that the normal X chromosome was late replic ating in most cells. The presence of Nager syndrome in this infant may be the result of critical breakpoints and/or position effects on chro mosome 9, inducing expression of a gene responsible for the syndrome.