The project will collect information on the mapping of clinical ratings on a number of scales that are used in the assessment of patients with ataxias.

Inclusion criteria

1. Patients aged 6-18 years with diagnosed with ataxia, preferably AT will be included. The diagnosis of AT will be made based on the criteria: typical clinical picture plus one of the following: 1. a proven mutation in the ATM gene 2. Deficient ATM protein proven by Western blotting 3. Elevated α-fetoprotein, cerebellar atrophy on MRI and immune deficiency/ chromosomal breakage/ T- cell lymphoreticular malignancy.
2. Children aged 6-18 years with suspected AT (fulfilling partially the above criteria will be included)
3. Children aged 6-18 years with AT like disease, with or without proven mutation in the MRE11 gene will be included
4. Children aged 6-18 years of age with ataxia of other known or unknown etiologies might be included, but their total number should not exceed 20% of the cohort in each site

Known patients with ataxia/ataxia telangiectasia