robertsonian translocation
Pronunciation: rob-ert-SOAN-ee-an
Chromosomal rearrangement where two acrocentric chromosomes join at their centromeres. Major cause of recurrent pregnancy loss and Down syndrome.
Full Definition
A specific type of chromosomal translocation involving the fusion of two acrocentric chromosomes (chromosomes 13, 14, 15, 21, or 22) at their centromeres, resulting in loss of the short arms and formation of a single large chromosome. This rearrangement occurs in approximately 1 in 1,000 individuals and is the most common form of chromosomal translocation in humans. While carriers are typically phenotypically normal, they face increased risks of producing chromosomally unbalanced gametes, leading to pregnancy loss, infertility, or offspring with chromosomal disorders such as Down syndrome when chromosome 21 is involved.
Usage
Usage note: Always specify which chromosomes are involved when discussing specific cases.
In Context
- "Genetic counseling emphasized that robertsonian translocation carriers face a 10-15% risk of chromosomally abnormal offspring." — Patient counseling notes
- "The karyotype report confirmed a 14;21 robertsonian translocation in the male partner." — Laboratory report