segmental aneusomy
Pronunciation: seg-MEN-tal an-YOU-so-mee
Gain or loss of a chromosome segment rather than entire chromosomes.
Full Definition
Segmental aneusomy refers to the presence of an abnormal copy number of a specific chromosomal segment, as opposed to entire chromosome aneuploidy. This can result from unbalanced translocations, deletions, duplications, or other structural rearrangements. In reproductive genetics, segmental aneusomies are particularly significant because they can cause specific genetic syndromes while maintaining normal overall chromosome counts, making them more challenging to detect through traditional screening methods. These abnormalities often arise from parental balanced structural rearrangements.
Usage
Usage note: Preferred term over 'partial trisomy' or 'partial monosomy' in modern genetic reports.
In Context
- "Microarray analysis detected segmental aneusomy involving a 2.5 Mb deletion on chromosome 15q11.2." — Chromosomal microarray report
- "The fetus showed features consistent with segmental aneusomy resulting from the father's balanced translocation." — Prenatal diagnosis report