missmonson

My husband has bent pinkies which is a single gene trait that he did not seem to inherit from his parents or grandparents in this case would it be considered a gene mutation and be a homozygous dominant with both allell's being dominant and therefore 100% of his offspring having bent pinkies? He has 2 sons and both of them have bent pinkies could he have a third that does not if he is a true homozygous dominant? Would a mutation that appeared first in him be homozygous dominant? Any help that I could get in this topic would be greatly appreciated.