SERPINA1 and Rare hereditary thrombophilia: However, this discrepancy is primarily explained by inclusion of gene-disease pairs characterized by adult onset [SERPINA1 (MIM: 107400); alpha-1 antitrypsin deficiency (MIM: 613490); HFE (MIM: 613609) and mild/unpredictable phenotype F5 (MIM: 612309); and factor V Leiden thrombophilia (MIM: 227400)].