RT Journal
A1 Mehta P
T1 Disorders of hemoglobin: Genetics, pathophysiology, and clinical management
JF JAMA
JO JAMA
YR 2012
FD March 28
VO 307
IS 12
SP 1319
OP 1319
DO 10.1001/jama.2012.348
UL http://dx.doi.org/10.1001/jama.2012.348
AB 
There are hundreds of different hemoglobins; some are specific for embryonic, fetal, and adult life, and others are variants. Some variants, such as hemoglobin S, have conferred protection for whole populations against malaria and other infectious diseases by trapping parasites within their membranes, allowing the parasites to be cleared in the reticuloendothelial system. Two prototypical abnormalities of hemoglobin account for most diseases: qualitative defects in heme (ie, sickle cell disease and its variants) and quantitative defects in the globin chain (ie, thalassemia). These latter abnormalities have become much better understood and amenable to study since the cloning and sequencing of human globin genes. More than a thousand globin chain variants have now been discovered, allowing for characterization of disease, elucidation of gene effects on protein encoding, and precise prenatal and postnatal diagnosis.