A t(14q22q) CHROMOSOME IN A LARGE KINDRED SPANNING FOUR GENERATIONS

Abstract

Translocations between D and G group chromosomes are not rare events, and usually involve chromosome numbers 14 and 21. The case presented here is that of a family with a t(14q22q) chromosome. The complete pedigree consists of 41 family members, 21 of whom are balanced t(14q22q) carriers. There have been no cases of Down's syndrome in the family. The index case was a 33 month old female who was seen because of physical and mental retardation. The proband was the product of a full term pregnancy and had an uncomplicated neonatal period; the mother was 34 and the father 35 years of age at her birth. The proband had a 45, XX, -D, -G, +t(DqGq) chromosome complement. The chromosomes involved in the translocation were numbers 14 and 22, which were identified by autoradiographic and G-banding techniques. All of the other balanced translocation carriers are phenotypically normal and in good health. There have been numerous miscarriages in the family, and 3 of the carrier males have had childless marriages. All 8 children of the first complete generation karyotyped carried the translocation which had been inherited from the father. Eleven of the next generation out of a total of 24 carried the translocation chromosome. There was no indication in this generation that the sperm carrying the translocation had a selective advantage; the carrier males produced 15 children, 6 of whom were carriers.