Neurologic Presentation in Children with Ataxia-Telangiectasia: Is Small Head Circumference a Hallmark of the Disease?

Abstract

To define the neurologic characteristics and course of ataxia-telangiectasia (A-T). Retrospective cross-sectional chart study of 57 children (ages 2 to 19 years) followed at an A-T clinic. Cerebellar and extracerebellar symptoms were graded according to degree of functional impairment. Head circumferences were plotted from the charts and z-scores were calculated and compared with that of family members. Ataxia was present in 87.7%, followed by dysarthria (82.1%), dysmetria (75.4%), bradykinesia (69.2%), hyperkinetic movements (58.9%), and dystonia (15.8%). All features aggravated with age. The most striking clinical observation in our patients was low head circumference (z-score below 1), which was present in 60.9%; 17% had true microcephaly (z-score below 2). Microcephaly appeared postnatally, was proportionate to height and weight, and did not correlate with severity of ataxia or genotype. In addition to cerebellar ataxia, extrapyramidal symptoms, especially bradykinesia, were frequent and disabling. Microcephaly is an integral part of A-T; understanding its pathogenesis may shed light on the mechanism by which ATM mutation causes dysfunction in the nervous system.