Trajectories of motor abnormalities in milder phenotypes of ataxia telangiectasia

Objective: To describe and classify the neurological trajectories in patients with mild neurological forms of ataxia telangiectasia (A-T) from the Dutch A-T cohort, combined with patients reported in the literature. Methods: Clinical, genetic and laboratory data of 14 A-T patients with mild neurological phenotypes from the Dutch cohort were analyzed and combined with corresponding data from the literature. A mild neurological phenotype was defined by a later onset, non-ataxia presenting or dominant feature, or slower progression compared to the classical A-T phenotype. Neurological trajectories were classified based on age of onset, presenting feature and follow-up data. Results: 105 patients were included in the study. Neurological trajectories were categorized into six groups: patients with childhood-onset extrapyramidal features with cerebellar symptoms developing later (group 1; 18 patients), childhood-onset cerebellar symptoms, with extrapyramidal features developing later (group...