Cytogenetic studies in a patient with a de novo t(Cq-;Gp+).

All the published instances of human transloca- tions involving group C and G chromosomes have been ascertained through a phenotypically abnormal child with an apparent partial C chromosome tri- somy. The translocation in a balanced state has been demonstrated in at least one member of each family. We are now reporting a t(Cq -;Gp +) in an 18-year-old girl whose initial chromosome analysis was part of the routine evaluation of children with psychiatric disorders. Her normal physical phenotype suggests that her translocation is probably balanced. The normal karyotypes of her parents and brother indicate that the translocation arose de novo, first manifesting in the proposita. This report includes the results of cytogenetic, dermatoglyphic, and gene marker studies of the proposita and her family.