I hope any of this is of use to you:
There is only one publication associated with this area and it is linked on that site – but here is the full version:
It’s rather unfortunate that there have been no more recent studies into this, but from the research available, it appears that by changing a Thymine to an Adenine (a missense variant), this would make the individual a carrier of universal congenital alopecia. It is unlikely that a recessive trait would show in an individual, but if their children were (owing to two carrier parents) A:A, it is likely that they would be fully hairless!
Admittedly, I would like some more studies, the article is held back by being focused on one Pakistani family, and I can’t immediately find follow up articles. I’d take it with a grain of salt and wait for more evidence before declaring it to be absolute that an person who was A:A would be bald everywhere.
Nevertheless, on the information available, and to answer your question based on that information- yes T:T are the common alleles, most people are T:T, A:T would be a carrier of universal alopecia so would probably show no effects, and A:A (according to this research) would have universal alopecia.
Again, due to the unfortunate lack of supporting studies, I cannot stress enough how much you should not take this as gospel.
Read more here: Source link