CTX is a congenital abnormality of lipid metabolism due to the deletion of the CYP27A1 gene at the 2q33-qter position, resulting in the inability of cholestanol and cholesterol to be metabolized efficiently and accumulating in multiple organs. The accumulation of cholestanol and cholesterol in multiple tissues leads to various pathologies. The symptoms of CTX may vary in different age groups. Patients with infantile onset often present with chronic diarrhea, juvenile patients often present with clinical signs of cataracts, juvenile to young adult patients are prone to xanthomas with fat accumulation in multiple tendons, and adult patients may present with degenerative central brain lesions. Incidence: Past studies have found that the incidence of this disease is about 1 in 50,000 among Caucasians; sporadic cases have been reported in other races, and no overall incidence estimates are available. Clinical features: Chronic diarrhea is the earliest symptom in infants and children, but is often overlooked; the earliest symptom detected in most patients (about 75%) is cataracts in early childhood (before age 10). With advancing age, progressive lesions of visual and central nervous degeneration appear; affected organs Clinical manifestations Eyes Cataracts; occur in approximately 75% of patients before age 10, with the remaining 25% often occurring after age 40 Other signs: palpebralxanthelasmas, opticnerveatrophy, ophthalmoplegia Protrusion According to Dottietal (2001), 13 adult cases were studied; opticdiskpaleness occurred in 50% of the cases and early onset retinal aging with retinal vascular sclerosis in 30% of the cases. Pyramidal signs (e.g., spasticity) and/or cerebellarsigns, as well as signs other than pyramidal signs; e.g., dystonia, atypical Parkinson’s disease, etc. Mental retardation or dementia (more often after age 20) Epilepsy (about half of patients) Peripheral neuropathy, body sensory abnormalities that may lead to peripheral muscle atrophy and pescavus pescavus) Neuropsychiatric symptoms; e.g., hallucinations, behavioral changes, agitation, depression Cardiovascular early-onset atherosclerosis and coronary artery disease Gastrointestinal chronic diarrhea in infants and children (earliest onset of symptoms) Gallstones (less common) Xanthomas often occur between 20 and 30 years of age, in Achilles tendon, hand and elbow extensors, knee and neck, and have occurred in the lungs, bones and central nervous system Skeletal granulomatous in the lumbar spine and femur Osteoporosis and fracture prone Endocrine hypothyroidism Premature aging includes premature cataracts, osteoporosis, tooth loss, atherosclerosis and neurological dementia Inheritance pattern: One chromosome recessive, if the parents are carriers, each carries one chromosome with the CYP27A1 gene. However, there is a 25% chance that each child will be born with the disorder regardless of gender, a 50% chance that the child will be a carrier like the parents, and a 25% chance that the child will be normal. Diagnosis: The diagnosis of this disease is based on the clinical signs of the patient, together with the relevant tests; the results of the tests are found Laboratory tests: elevated cholestanol in blood and tissues Low or normal cholesterol in blood Abnormal synthesis of primary bile acids resulting in chenodeoxycholic acid Significantly low bilealcohols and glyconjugates in bile, blood and urine Elevated cholestanol and Apolipoprotein B in cerebrospinal fluid Enzyme examination Significantly low sterol 27-hydroxylation activity in skin sections, blood and liver Imaging MRI of the brain Abnormalities in the dentatenuclei, cerebellum, and white matter may be found Genetic testing can identify the CYP27A1 gene defect by Sequenceanalysis in most patients (99-100%) Treatment: Long-term treatment is provided in conjunction with a team of specialists to provide complete treatment. In terms of pharmacological treatment, Chenodeoxycholicacid (CDCA; adult daily dose of about 750 mg) can be used to improve metabolic abnormalities, normalize the synthesis of cholestrol, and achieve normal blood, bile, and urine test values, with the hope of improving central nervous system degeneration and slowing down lesions in various tissues and organs. In a study by Mondellietal (2001), who treated patients with CDCA for 11 years, it was found that after 4 months of treatment, the nerve conduction rate was normalized and stabilized by evoked potentials, and the deterioration of other clinical signs was reduced. The improvement in symptoms is still better than in other untreated patients. In addition, HMG-CoAreductaseinhibitors are recommended for use alone or in combination with CDCA to reduce the accumulation of cholesterol and thereby alleviate symptoms; however, past treatment experience has shown that these drugs may have side effects such as muscle damage and rhabdomyolysis, so their use in clinical practice should be evaluated with caution. Neurological symptoms, such as epilepsy and atypical Parkinson’s disease, require medication or rehabilitation depending on their symptoms. For cataracts that often occur in early childhood, regular visits to the ophthalmologist are required to consider corrective eye surgery depending on the severity of the visual impairment. In terms of long-term follow-up, patients need to have their blood cholesterol and related metabolic values, neurological examinations, cardiac ultrasound, brain MRI, and whole-body bone density checked annually in order to monitor the disease at all times, understand its progress, and receive appropriate medical treatment.