Individuals with a neurodegenerative disease called spinocerebellar ataxia 11 (SCA11) have mutations in a gene called TTBK2, according to a study to be published online in Nature Genetics. TTBK2, which encodes the protein tau tubulin kinase 2, functions in a pathway that has also been implicated in Alzheimer's disease.
Henry Houlden and colleagues studied two families with SCA11, which is one of a group of similar spinocerebellar ataxias, and is characterized by poor coordination, abnormal eye movement, and impairment of speech and swallowing. The authors identified mutations in TTBK2 in affected individuals from a family in Devon, England, some of whose members have had the disease going back eight generations. They also report TTBK2 mutations in affected individuals from a Pakistani family.
Tau tubulin kinase 2 is an enzyme that adds phosphate groups to a protein called tau, whose accumulation in phosphorylated form has been associated with the progression of Alzheimer's disease and other neurodegenerative disorders. Another member of this protein family, TTBK1, has been shown to phosphorylate tau proteins at sites that are identical to those observed in Alzheimer's disease. The study by Houlden and colleagues is the first report of a genetic defect in a tau kinase in any neurodegenerative disease, and suggests that further study of SCA11 may shed light on the molecular basis of other so-called 'tauopathies'.
Henry Houlden (Institute of Neurology, London, UK)
Abstract available online.
(C) Nature Genetics press release.
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