Ataxia telangiectasia

Ataxia telangiectasia (McKusick 208900) is a
pleiotropic, variable disease due to mutations in
the ATM gene on chromosome 11q23. Preferential
reciprocal translocations between chromosomes
7 and 14 with breakpoints at 7p14, 7q14,
14q11, and 14q32 occur in a small proportion of
metaphases. The ATM gene has 66 exons spanning
more than 150 kb of genomic DNA. From
its 13-kb transcript (and smaller alternatively
spliced products), a 3056-amino-acid protein
kinase ATM(350 kDA) is translated. ATM is activated
in response to double-strand DNA breaks.
It is part of a network of proteins that regulate
cellular responses to DNA damage (p. 80). Clinically
different disorders are related at the cellular
level