Tina Ankar's teenage years are marked by strange growths appearing across her body, the kind of symptom that sends doctors chasing the wrong diagnosis for years before anyone names cerebrotendinous xanthomatosis, or CTX. The episode follows her path from confusing early complaints to a rare-disease diagnosis, using interviews and reenactments in the Mystery Diagnosis format to show how a genetic disorder can be mistaken for something else entirely. It explains the biology plainly: CTX comes from mutations in the CYP27A1 gene on chromosome 2, inherited only when both parents pass along a defective copy, and it belongs to a group of disorders called leukodystrophies that affect how the body processes cholesterol. Once identified, the disease is treated with chenodeoxycholic acid replacement therapy, with statins like simvastatin added when cholesterol stays high. The film also touches on a second patient whose symptoms, including pain tied to her menstrual cycle, sent her doctors down an equally wrong path first. The point throughout is how long a rare genetic disease can hide behind more common-looking symptoms.