Ataxia-telangiectasia (AT) is a primary immunodeficiency disorder that occurs in an estimated incidence of 1 in 40,000 to 1 in 300,000 births (Lederman, 2000). AT is characterized by progressive cerebellar ataxia, oculocutaneous telangiectasia, progressive cerebellar dysfunction, and recurrent sinopulmonary infections secondary to progressive immunological and neurological dysfunction (Boder, 1958). AT patients are significantly predisposed to cancer, particularly lymphomas and leukemias. Other manifestations of the disease include sensitivity to ionizing radiation (Taylor et al., 1975), premature aging, and hypogonadism (Regueiro et al., 2000). AT has been a major interest of scientists since the 1960’s because it may yield an insight into numerous other major health problems, such as cancer, neurological disease, immunodeficiency, and aging (Lederman, 2000).

The responsible gene in AT, ataxia-telangiectasia mutated (ATM), was discovered in 1995. Researchers linked the hyper-sensitivity of AT patients to ionizing radiation (IR) and predisposition to cancer to “chromosomal instability, abnormalities in genetic recombination, and defective signaling to programmed cell death and several cell cycle checkpoints activated by DNA damage” (Canman, 1998). Earlier observations predicted that the gene altered in AT played a role in DNA damage recognition. These predictions were confirmed when a single gene on chromosome 11 was discovered (Savitsky et al., 1995, Gatti et al., 1982). Since its discovery, the protein product of the ATM gene has been shown to be a part of eukaryotic cell cycle control, DNA repair, and DNA recombination (Lavin, 2004).

Telangiectasias are smalls, red 'spider' veins. These typically appear on the surface of the ears and cheeks or in the corners of the eyes in patients with AT.

The 'ataxia' part of the name refers to the difficulty patients with AT have walking. At early age, the child's walking becomes wobbley, at teens handicapped-bound and at the early 20s, it becomes fatally.

In AT, ATM (ataxia telangiectasia mutated) kinase is abnormal. It is important for the surveillance and repair of damaged DNA.

External links

• Replication-Independent Double-Strand Breaks (DSBs) - Discusses importance of ATM kinase
• Ataxia Telangiectasia - NINDS Information Page