The 3 cases included diagnoses of Creutzfeldt-Jakob disease, spinocerebellar ataxia due to AFG3L2 heterozygosity, and neurolymphomatosis due to Sézary syndrome.18-20 The case investigations provided included blood test results, MRI findings, neurophysiology interpretations, lumbar puncture results, and histopathology reports. The gene discussed is AFG3L2; the disease is cerebellar ataxia.