Recognition of cerebrotendinous xanthomatosis (CTX) may be difficult because of its clinical heterogeneity and the absence of consistent genotype-phenotype correlations. Early diagnosis of CTX is crucial because CTX is a treatable disease, and early and long-term treatment with chenodeoxycholic acid (CDCA) improves clinical outcome substantially. Many studies have already reported positive effects of CDCA treatment on the disease course of CTX, not only with normalization of biochemical abnormalities, but also stabilization and/or improvement of clinical symptoms. In this chapter, the largest retrospective study reporting the clinical long-term follow-up and magnetic resonance imaging (MRI) characteristics of Dutch patients with CTX is discussed, together with other published studies. Treatment start at an early age can reverse and even prevent the development of neurologic symptoms; therefore, the importance of early diagnosis in CTX is critical.