ataxia telangiectasia
an autosomal recessive genetic disorder characterized primarily by an inability to coordinate voluntary muscle movements and by the dilation of small blood vessels in the eyes and skin of the nose and ears. Initial symptoms include limb ataxia and truncal ataxia (swaying of the head and trunk while standing or sitting), which eventually become so severe that the individual must remain in a wheelchair. Other symptoms include increasingly slowed speech, the appearance of such movements as myoclonus or intention tremors (see action tremor), and a proneness to infection, particularly respiratory infection. Also called Louis-Bar syndrome.