This is one of the websites that talks about
It does seem to be hereditary so since it's in the family, it would seem to me that you and any siblings you have as well as cousins on your Dad's side should be tested. The article says a complete blood count and maybe other blood tests are needed. And, as I said, anemia is a symptom so that must be why he's tired.
If the doctor is not following up on these tests, then for goodness sakes, he needs another doctor who will! It took just seconds to Google this and get information about
Keep us updated. You're a good daughter to seek the best care for both your parents!
Laniediabetes moderatordiabetes type 2 controlled by diet and exercise and
very low carb way of eating