New drugs may follow the identification of mutations in the JAK2 gene involved in Down’s Syndrome-associated acute lymphoblastic leukaemia (ALL).
Researchers thought JAK2 mutations might be common to ALL associated with Down’s Syndrome because they are implicated in cancers affecting other types of white-blood-cell (myeloproliferative) disorders.
Marrow samples from 87 patients with Down’s Syndrome-associated ALL revealed that 16 (18%) had somatically acquired JAK2 mutations. Children with a JAK2 mutation were younger at diagnosis with ALL (4.5 years) compared with those who did not have this mutation (8.6 years).
Five mutations (alleles) were identified, each affecting a single amino-acid residue in the protein encoded by the gene, known as R683.
The research by Dr Shai Izraeli and colleagues at the Sheba Medical Center in Israel is published in an upcoming edition of The Lancet.
The authors conclude that a specific association exists between the type of somatic mutation in the JAK2 gene and the development of conditions such as ALL.
They say: “Somatically acquired R683 JAK2 mutations define a distinct acute lymphoblastic leukaemia subgroup that is uniquely associated with Down’s Syndrome. JAK2 inhibitors could be useful for treatment of this leukaemia.”
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