Medical records indicated hemochromatosis in 1.6% of HBB LoF heterozygotes vs. 0.4% of those without HBB LoF variants, 2.4% vs. 0.007% had hepatic fibrosis, and 2.2% vs. 0.3% had nonalcoholic cirrhosis, indicating that complications of iron overload can be a concern for HBB LoF heterozygotes. The gene discussed is HBB; the disease is hemochromatosis type 1.