Incomplete penetrance likely contributed to the discrepancy between GP and reported prevalence in certain AD diseases such as TGIF1-associated holoprosencephaly, or hypomorphic variants in AR phenotypes like cystic fibrosis or hemochromatosis, particularly when the least conservative variant set (P + LP + VUS-H) was used [43]. This evidence concerns the gene TGIF1 and hemochromatosis.