Inheritance exam qu help

Hi,
Got an exam question about a disease called Crigler-Najjar syndrome which is caused by a recessive allele.
People with the disorder can't break down a toxic waste product from the liver.
It talks about an isolated community where the disorder is more common (obviously more interbreeding).

The question says:
It may be possible to repair the defective gene in the liver cells of affected individuals. Successful gene therapy of all individuals with this disorder in this community might increase the frequency of C-N syndrome in future generations.
Suggest how.

I have no idea, because I assumed the gene therapy would prevent people getting the disease in the future because you're replacing the fault gene???

Please help :smile:

Reply 1

Kvothe the Arcane

In gene therapy, modifications affect the individual patient only, and are not inherited by offspring. So while what would usually happen is the frequency of such an unfavourable allele would be low due to natural selection, the gene therapy means that there it's no longer going to be selected against as the disadvantage is combated by the treatment.