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R117H negative for 5T

My husband and I are both carriers of identical strains. R117H negative for 5T. Are there any documented cases with this combination and what CF symptoms developed. Our son has both genes.
Dear questioner, thank you for your question.

The R117H mutation is considered as a ‘mild' mutation. It can cause a mild kind of CF. It can also lead to infertility in men, but it usually does not imply severe disease. The factors that determine whether R117H provokes the disease or not are not fully understood. In any case the T tract influences disease severity: mainly subjects who carry T5 on the R117H allele have a higher risk of developing lung disease.

A study of 2 Dutch individuals with two copies of a R117H mutation (7T variant) was reported in 2011. The CFTR activity in airways and intestine was within the normal range. However the male patient was infertile (1)

If you are planning to get genetic counseling, you will get even more detailed information on this topic.

Best wishes
Katherine O’Neill


(1). R.A. de Nooijer, J.M. Nobel, H.G.M. Arets, A.G. Bot, F. Teding van Berkhout, Y.B. de Rijke, H.R. de Jonge, I. Bronsveld, Assessment of CFTR function in homozygous R117H-7T subjects, Journal of Cystic Fibrosis, Volume 10, Issue 5, September 2011, Pages 326-332, ISSN 1569-1993,


The answer is edited by: Katherine O'Neill
2.12.13 Please find even more information on the topic R117H/7T under the following links:

D. d'Alquen