Hereditary persistence of fetal hemoglobin
Encyclopedia
Hereditary persistence of fetal hemoglobin (HPFH, BrE: Hereditary persistence of foetal haemoglobin) is a benign condition in which significant fetal hemoglobin (hemoglobin F) production continues well into adulthood, disregarding the normal shutoff point after which only adult-type hemoglobin should be produced.
s in the β-globin gene cluster. The percentage of incorrect expression might be as low as 10-15% or as high as 100% of the total hemoglobin, usually higher in homozygotes than in heterozygotes.
and thalassemia
s, 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 Americans of African and Greek descent.
Causes
This is usually caused by mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s in the β-globin gene cluster. The percentage of incorrect expression might be as low as 10-15% or as high as 100% of the total hemoglobin, usually higher in homozygotes than in heterozygotes.
Epidemiology
HPFH may alleviate the severity of certain hemaglobinopathiesHemoglobinopathy
Hemoglobinopathy is a kind of genetic defect that results in abnormal structure of one of the globin chains of the hemoglobin molecule. Hemoglobinopathies are inherited single-gene disorders; in most cases, they are inherited as autosomal co-dominant traits. Common hemoglobinopathies include...
and thalassemia
Thalassemia
Thalassemia is an inherited autosomal recessive blood disease that originated in the Mediterranean region. In thalassemia the genetic defect, which could be either mutation or deletion, results in reduced rate of synthesis or no synthesis of one of the globin chains that make up hemoglobin...
s, and is selected for in populations with a high prevalence of these conditions (which in turn are often selected for in areas where malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
is endemic). Thus, it has been found to affect Americans of African and Greek descent.