Five generations of t(4;8)(q35;q13) leading to a case of partial 8q trisomy with consideration of potential pregnancy outcomes from translocation carriers

We describe a female infant with partial trisomy 8q who has microphthalmia, a cleft palate, micrognathia and a heart defect. Her dysmorphogenetic features closely resemble the characteristic pattern seen in the 17 cases thus far reported in the literature. Her chromosomal defect was caused by an unbalanced translocation, inherited through her father, and found to have been transmitted through at least 5 generations. Recently developed models designed to predict the most probable mode of unbalanced segregation from the meiotic quadrivalent and the likelihood that a chromosomally unbalanced fetus will survive to term are applied to this family's translocation. Also, the frequencies of potential reproductive outcomes from carriers of this translocation generated from empiric data are considered as a requisite aid to genetic counseling.