About 10% of the population has an HbF level >1.0%.<unk>  may alleviate the severity of certain<unk> opathies and thalassemias, and is selected for in populations with a high prevalence of these conditions (which in turn are often selected for in areas where malaria is endemic). Thus, it has been found to affect people of African and Greek descent.
Hereditary persistence of fetal hemoglobin
Paroxysmal nocturnal hemoglobinuria
Paroxysmal cold hemoglobinuria
Beta thalassemia
Neonatal alloimmune thrombocytopenia
Congenital hemolytic anemia
Gestational thrombocytopenia
Hemoglobin Lepore syndrome