Risk factor for blood diseases

A common genetic sequence abnormality that enhances the likelihood of acquiring a mutation in a gene linked to blood diseases has been identified, according to three studies published online this week in Nature Genetics.

Nicholas Cross, Robert Kralovics, and Ross Levine carried out independent case-control studies to identify a collection of mutations that occur in the JAK2 gene, that do not arise from random mutagenesis but rather are specifically determined by the DNA sequence. JAK2 is a protein with enzymatic activity that is linked to the abnormal production of several types of blood cells, called myeloproliferative neoplasms, found in patients with who suffer from this disorder.

Myeloproliferative neoplasms arise from the bone marrow and over 50% of patients afflicted with this blood disorder carry the JAK2 mutation and suffer from the overproduction of red blood cells, platelets, or fibrous connective tissue. Understanding the underlying inherited sequence partly explains the predisposition for acquiring mutations in certain disease-specific genes and may help explain why some individuals are at higher risk in developing a disease.