International Ataxia Rating Scale in Younger Patients

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