Carrier of the CFTR gene, genotype IVSR8-POLYT 7T/7T.

Question

Hello, I am in the 8th week of pregnancy and have undergone cystic fibrosis testing for 75% of mutations.

The result was that none of the targeted genetic variants were detected in my CFTR genotype, which was IVS8:7T/7T.

However, my midwife called me and told me that, according to the test, I am considered a carrier of this particular gene and that my husband should also be tested for 99% of mutations.

My question is: For the baby to be at risk, does my husband need to carry any mutation, or only this specific one?

I am very worried because, besides this being an IVF pregnancy, it is also my first pregnancy.

I would greatly appreciate your answer.

Answer

The detected variant (IVS8:7T/7T) is not pathogenic and should not have been included in the report. Based on this result, you are not considered a carrier of a pathogenic cystic fibrosis variant.

Carrier screening recommendations, especially in populations with high genetic diversity, such as the Greek population, suggest conducting a more extensive test that covers at least 90% of pathogenic variants.

With your current results, you are not considered a carrier. However, if you wish, you may choose to undergo a **comprehensive CFTR gene screening**. If this test also comes back negative, **there is no reason for concern** for this or any future pregnancies.

If donor eggs or sperm were used in the IVF process, the screening should be performed on the donors.

Cystic fibrosis is caused by various mutations in the CFTR gene. The baby is at risk of developing the disease only if it inherits two pathogenic variants — either the same or different — from both parents.

If both parents are carriers of a pathogenic mutation, there is a:
- 25% chance that the baby will have cystic fibrosis,
- 50% chance that the baby will be a carrier,
-25% chance that the baby will not carry any mutation.
Best regards,
M Poulou

25.04.2025