Immune dysfunction is one of many defects.

Ataxia-telangiectasea (AT), a progressive and uniformly fatal inherited neuroimmunological disorder, affects approximately 1 in 40 000 children. Patients are born to normal parents and appear to develop normally for about two years. They then begin to stagger (ataxia) and show signs of degenerating cerebellar function; by five years of age, they have dilated blood vessels (telangiectases) over the exposed bulbar conjunctiva and skin of the ear. By 10 years of age, they are usually confined to a wheel-chair. Most AT patients have IgA and IgG2 deficiency as well as various T cell-associated immune dysfunctions. Because one of every five patients develops cancer, usually lymphoid, during their shortened life-span, it is believed that unravelling the pathogenesis of AT will also shed light upon the genetics of cancer susceptibility and upon the relationship of immunodeficiency to oncogenesis. A recent conference(∗) focused on four areas of this complex disorder: DNA repair/replication, genetics, neuropathology and immunopathology.