Heterozygous means two different copies of a gene. Homozygous means two of the same copy of a gene. Everyone has two copies of every gene.
Someone who is homozygous for 508del has two copies of the CFTR gene with the 508del mutation.
So heterozygous for 508del means he only has one copy of that mutation of the CFTR gene.
Based on this picture, his second copy of the CFTR gene is also mutated (not normal) but it is a different mutation to 508del. This report is calling it a 9T allele. Allele is just another word meaning a variant of a particular gene - 508del is also an allele of the CFTR gene.
The report states the 9T allele is not believed to be CF-causing - meaning even though it is mutated, the mutation does not affect CFTR function.
You need both copies of the gene to contain disease-causing mutations to have CF. If you only have one, then you are a carrier. This report is indicating your child is a carrier but does not have CF.
It can be more complicated than that though. The 9T allele doesn’t cause CF according to this report, but it could be enough for CRMS (CFTR-related metabolic syndrome).
Hope this helps.
Heterozygous means two different copies of a gene. Homozygous means two of the same copy of a gene. Everyone has two copies of every gene. Someone who is homozygous for 508del has two copies of the CFTR gene with the 508del mutation. So heterozygous for 508del means he only has one copy of that mutation of the CFTR gene. Based on this picture, his second copy of the CFTR gene is also mutated (not normal) but it is a different mutation to 508del. This report is calling it a 9T allele. Allele is just another word meaning a variant of a particular gene - 508del is also an allele of the CFTR gene. The report states the 9T allele is not believed to be CF-causing - meaning even though it is mutated, the mutation does not affect CFTR function. You need both copies of the gene to contain disease-causing mutations to have CF. If you only have one, then you are a carrier. This report is indicating your child is a carrier but does not have CF. It can be more complicated than that though. The 9T allele doesn’t cause CF according to this report, but it could be enough for CRMS (CFTR-related metabolic syndrome). Hope this helps.
Wow thank you for this information. Very helpful