What is "huntingtin"

n. (context protein English) A protein whose polymorphism is associated with Huntington's chorea

The huntingtin gene, also called the HTT or HD (Huntington disease) gene, is the IT15 ("interesting transcript 15") gene, which codes for a protein called the huntingtin protein. The gene and its product are under heavy investigation as part of Huntington's disease clinical research and the suggested role for huntingtin in long-term memory storage.

It is variable in its structure, as the many polymorphisms of the gene can lead to variable numbers of glutamine residues present in the protein. In its wild-type (normal) form, it contains 6-35 glutamine residues. However, in individuals affected by Huntington's disease (an autosomal dominant genetic disorder), it contains more than 36 glutamine residues (highest reported repeat length is about 250). Its commonly used name is derived from this disease; previously, the IT15 label was commonly used.

The mass of huntingtin protein is dependent largely on the number of glutamine residues it has, the predicted mass is around 350 kDa. Normal huntingtin is generally accepted to be 3144 amino acids in size. The exact function of this protein is not known, but it plays an important role in nerve cells. Within cells, huntingtin may be involved in signaling, transporting materials, binding proteins and other structures, and protecting against programmed cell death ( apoptosis). The huntingtin protein is required for normal development before birth. It is expressed in many tissues in the body, with the highest levels of expression seen in the brain.