Which PGT test detects chromosomal structural rearrangements?

• A. PGT-A
• B. PGT-M
• C. PGT-SR
• D. PGT-D

Answer: (C)

Detecting chromosomal structural rearrangements requires a test that analyzes how chromosome segments are arranged, not just how many copies exist. Structural rearrangements—such as balanced translocations or inversions—can produce unbalanced embryos even when the overall chromosome count appears normal. Preimplantation Genetic Testing for Structural Rearrangements is specifically designed to identify these rearrangements in embryos, so only embryos with normal or balanced configurations are recommended for transfer. This focus helps reduce miscarriage risk and the chance of chromosomal imbalance in the baby.

In contrast, tests designed for whole-chromosome copy number (aneuploidy) screening look at how many copies of entire chromosomes are present, which may miss or be unrelated to a rearrangement. Tests for single-gene disorders (monogenic conditions) search for specific gene mutations, not for how chromosome pieces are organized. The remaining category covers other diagnostic aims not centered on chromosome structure, so it wouldn’t target structural rearrangements.