Due To Covid-19 there were delays in the arrival of patients to the sites. Due to the rare disease in the study population, no patients who met the inclusion/exclusion criteria were found, and the study was terminated early due to these reasons.

The prevalence of CTX in our country is estimated to be 1 / 50.000. The aim of this study is to screen more volunteers by conducting a larger screening from neurology and pediatric metabolism clinics in Turkey.

This observational study was designed retrospectively and prospectively in two stages. In the retrospective section, the patient database and / or patient files will be screened in the neurology and pediatric metabolism clinics and the patients aged 40 and below in the neurology clinics with at least two of the following will be enrolled to the study:

• Ataxia and / or spasticity
• Bilateral cataract (except senile cataract)
• Intellectual limitation
• Non-enhancing hyperintensity on T2 sections in MR imaging of dentate nuclei
• Autosomal recessive transition pattern. (Ex: Relative Marriage)

In the pediatric metabolism centers, cases suspected of CTX and planned to apply the Mignarri Index according to the investigator's opinion will be identified.

Inclusion Criteria:

I-1. Giving written informed consent

I-2. Patients in neurology clinics should have been identified with at least two of the following:

• Ataxia and / or spasticity
• Bilateral cataract (except senile cataract)
• Intellectual limitation
• Nonintensitive hyperintensity in T2 sections on MRI of the dentate nucleus
• Forming an autosomal recessive transition pattern. (Ex: Relative Marriage)

I-3. In the pediatric metabolism centers, cases suspected of CTX and planned to apply the Mignarri Index according to the investigator's opinion.

I-4. On the day the patient signed the Informed Consent Form, the patient did not get older than 41 years of age (subjects aged 40 and under will be included in the study)

Exclusion Criteria:

E-1. The patient's ataxia and / or spasticity, cataract, intellectual limitation, and non-contrasted hyperintensity of T2 sections in MR imaging of dentate nuclei with typical MRI findings are due to a known cause other than CTX or other underlying disease.

E-2. The patient has participated in an interventional clinical study in the last 30 days,

E-3. The patient and / or his / her legal representative does not give consent to participate in the study,

E-4. In the opinion of the investigator, the patient is not able to fulfill the working requirements appropriately,

E-5. Pregnancy and / or lactation

E-6. If the patient was 41 years old when included in the study.

200 patients