Direct assessment of hereditary hemochromatosis in preimplantation genetic testing

Hereditary hemochromatosis (HH) is a common genetic disorder characterized by iron overload, which, if undiagnosed, can lead to severe organ damage. There are 4 types of HH. Type 1 HH, the most common form, is primarily caused by a common variant in Western Europe (p.Cys282Tyr, C282Y, or c.845 G>A). It is generally preventable during in vitro fertilization if proper genetic testing is performed before implantation. Here, we demonstrated a direct detection and cost-effective approach using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in preimplantation genetic testing (PGT) settings.

We began by validating the assay with genomic deoxyribonucleic acid (DNA) from Coriell cell lines of known HFE C282Y genotypes, followed by testing patients' genomic DNA samples. After establishing the assay on genomic DNA, we extended the assay to whole-genome amplified DNA from embryo biopsies.

The subjects include cell line samples and human specimens and human embryo biopsies.

Patients and embryos either carried or did not carry the HFE C282Y variant in their genome. No intervention was applied.

The readout included the genotype of samples at the HFE C282Y locus and accuracy of PCR-RFLP results.

An accuracy of >99% was achieved across 80 cell line samples, 38 patient samples, and 81 embryo biopsies.

In this study, we demonstrated the feasibility of using the PCR-RFLP approach to PGT. Specifically, we validated the assay for the HFE C282Y variant, the primary cause of type 1 hemochromatosis. The assay was tested on genomic DNA and DNA resulting from whole-genome amplification, achieving >99% accuracy, sensitivity, precision, and specificity. These results also suggest the possibility for extending the PCR-RFLP approach to cover a broader range of conditions, such as spinal muscular atrophy, to benefit more patients currently ineligible for testing at PGT laboratories.