Glossary · Definition · v2026.3
What Is Segmental Aneuploidy?
Segmental aneuploidy refers to a gain or loss of a portion of a chromosome rather than a whole chromosome. It is detected during preimplantation genetic testing and represents a distinct category from whole-chromosome aneuploidy.
Clinical significance
Segmental aneuploidies can result from structural rearrangements such as translocations or deletions. Their clinical significance varies depending on the chromosome region involved, the size of the segment, and whether the abnormality is inherited or de novo.
Common confusion
Segmental aneuploidy is not the same as mosaicism. Segmental refers to a partial chromosome gain or loss, while mosaicism refers to a mixture of chromosomally normal and abnormal cells within the same embryo.
Related reference
Used in
This content defines terminology for educational orientation. It does not constitute medical advice.
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