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PubMed This is a summary of 24 peer-reviewed journal articles Updated
Medical Genetics

Understanding Your Diagnosis: An Introduction to CTX

At a Glance

Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder where the body cannot properly break down cholesterol, causing a toxic buildup of cholestanol. Fortunately, it is highly treatable with chenodeoxycholic acid (CDCA), which can stop disease progression and protect the nervous system.

Receiving a diagnosis of Cerebrotendinous Xanthomatosis (CTX) can feel overwhelming, but it also brings a critical turning point: you now have a name for what is happening and a clear path forward. CTX is a rare autosomal recessive metabolic disorder, meaning a person must inherit a copy of a mutated gene from both parents to develop the condition [1][2]. While the diagnosis is life-changing, understanding the mechanics of the disease and the effectiveness of modern treatment can provide significant stability.

Foundations of Your Diagnosis

CTX is caused by mutations in the CYP27A1 gene [3][4]. This gene is responsible for producing an enzyme called sterol 27-hydroxylase, which lives in the mitochondria (the energy-producing parts of cells) and helps the body break down cholesterol into bile acids [5][4].

In a person with CTX, this enzyme is either missing or doesn’t work correctly. This creates a “metabolic traffic jam”:

  • The Buildup: Because the body cannot convert cholesterol into bile acids properly, it produces high levels of “off-target” substances, specifically cholestanol and bile alcohols [5][6].
  • The Damage: These substances are toxic. Over time, they accumulate in various tissues, including the brain, spinal cord, and tendons [7][8].
  • The Result: This accumulation leads to the characteristic signs of CTX, such as xanthomas (fatty deposits often found on the Achilles tendon), juvenile cataracts, and neurological challenges [7][8][9].

Why CTX is Rare but Often Missed

CTX is considered a rare disease, but experts believe it is significantly underdiagnosed [10][11]. Because its symptoms—like chronic diarrhea in infancy or early cataracts—can seem unrelated, many patients spend years visiting different specialists before the pieces are put together [12][13].

While it affects people globally, a higher prevalence has been noted in certain populations, particularly within Moroccan/Sephardic Jewish and Druze communities [14]. Increased awareness and the potential for newborn screening are currently being advocated to help catch the condition before major symptoms appear [14][15].

Three Stabilizing Facts for the Journey Ahead

When facing a new diagnosis, it is helpful to focus on three key realities of CTX:

  1. It is highly treatable. Unlike many rare genetic disorders, there is a standard-of-care medication called chenodeoxycholic acid (CDCA) [1][7]. CDCA replaces the bile acid your body is missing, which tells your system to stop overproducing the toxic cholestanol [7][16].
  2. Treatment can stop progression. When started early, CDCA therapy can halt the progression of the disease and, in some cases, even improve or reverse existing neurological symptoms [17][18]. Consistency is vital; staying on the medication prevents further damage [19][20].
  3. The disease moves slowly. CTX is a progressive disorder that typically develops over decades [8][21]. This “slow-motion” nature often gives families and doctors time to implement a treatment plan and monitor its effectiveness through regular blood tests for cholestanol levels [19][22].

Looking Forward

The goal of care for CTX is straightforward: lower the toxic levels of cholestanol in the body to protect the brain and nervous system [23][7]. By working closely with a metabolic specialist and maintaining a strict treatment regimen, many individuals with CTX can lead stable lives and prevent the most severe complications of the condition [24][17].

Common questions in this guide

What causes cerebrotendinous xanthomatosis (CTX)?
CTX is caused by inherited mutations in the CYP27A1 gene. This mutation prevents the body from producing a specific enzyme needed to break down cholesterol, leading to a toxic buildup of cholestanol in tissues like the brain and tendons.
What are the early symptoms of CTX?
Early signs of CTX often include chronic diarrhea in infancy and the development of juvenile cataracts. As the disease progresses, fatty deposits called xanthomas may appear on the Achilles tendon, along with various neurological challenges.
Is there a treatment for CTX?
Yes, CTX is highly treatable. The standard treatment is a medication called chenodeoxycholic acid (CDCA), which replaces the missing bile acid in the body and stops the toxic overproduction of cholestanol.
Can CDCA treatment reverse CTX symptoms?
When started early, CDCA therapy can successfully halt the progression of the disease. In some cases, consistent treatment may even improve or reverse existing neurological symptoms.
How do doctors monitor if CTX treatment is working?
Doctors typically track treatment success by regularly measuring your cholestanol levels through blood tests. Consistently keeping these toxic levels low is the primary goal to prevent further damage.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Can you explain the specific genetic mutation found in the CYP27A1 gene and what it means for my (or my child's) case?
  2. 2.Based on our current symptoms, has the disease progression been caught early enough to potentially reverse some of the effects with CDCA treatment?
  3. 3.What is my (or my child's) baseline cholestanol level, and how often will we monitor it to ensure the treatment is working?
  4. 4.Are there any other specialists, such as a neuro-ophthalmologist or a metabolic dietitian, that should be part of our care team?
  5. 5.Should my other children or close relatives be tested for the CYP27A1 mutation, even if they don't have symptoms yet?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (24)
  1. 1

    FDA Approves First Targeted Treatment for Cerebrotendinous Xanthomatosis: A Perspective on a Landmark in Rare Lipid Storage Disease Therapy.

    Jalal L, Basaria AAA, Yokolo H

    Health science reports 2025; (8(12)):e71549 doi:10.1002/hsr2.71549.

    PMID: 41324091
  2. 2

    Clinical and Imaging Profile of Patients with Cerebrotendinous Xanthomatosis - a Video Case Series from India.

    Katragadda P, Holla VV, Kamble N, et al.

    Tremor and other hyperkinetic movements (New York, N.Y.) 2024; (14()):10 doi:10.5334/tohm.851.

    PMID: 38476584
  3. 3

    Cerebrotendinous xanthomatosis: The rare "treatable" disease you never consider.

    Raymond GV, Schiffmann R

    Neurology 2019; (92(2)):61-62 doi:10.1212/WNL.0000000000006721.

    PMID: 30530794
  4. 4

    Cytological diagnosis of cerebrotendinous xanthomatosis in two siblings presenting with bilateral ankle swellings and neurological decline.

    Nambirajan A, Sashidharan A, Garg A, et al.

    Cytopathology : official journal of the British Society for Clinical Cytology 2018; (29(5)):482-485 doi:10.1111/cyt.12573.

    PMID: 29737592
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    Cerebrotendinous Xanthomatosis: A Treatable Genetic Disease Not to Be Missed.

    Varman KM, Dunbar K, Usifo K, Stevens CA

    Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases 2016; (22(2)):92-3 doi:10.1097/RHU.0000000000000367.

    PMID: 26906304
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    Cerebellar hypometabolism with normal structural findings in Cerebrotendinous xanthomatosis. A case report.

    Ragno M, Di Marzio F, Fuccio C, et al.

    Clinical neurology and neurosurgery 2015; (139()):221-3.

    PMID: 26519892
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    A Preventable Ataxia: Cerebrotendinous Xanthomatosis.

    Shaji B, Srikumar B, Ramachandran D

    Annals of Indian Academy of Neurology 2019; (22(4)):493-496 doi:10.4103/aian.AIAN_126_18.

    PMID: 31736580
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    Cerebrotendinous Xanthomatosis, a Treatable Disorder Often Missed: Case Series of Three Patients Confirmed by Genetic Testing.

    Yaqoob A, Dar WR, Raina A, et al.

    Neurology India 2024; (72(1)):138-141 doi:10.4103/ni.ni_1093_21.

    PMID: 38443015
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    Diagnostic challenge: A case of late-onset spinal form cerebrotendinous xanthomatosis.

    Mutlu D, Tuncer A, Gocmen R, et al.

    Neurology 2019; (92(9)):438-439 doi:10.1212/WNL.0000000000007015.

    PMID: 30804055
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    Clinical, biochemical, and molecular insights into Cerebrotendinous Xanthomatosis: A nationwide study of 100 Turkish individuals.

    Zubarioglu T, Kıykım E, Köse E, et al.

    Molecular genetics and metabolism 2024; (142(2)):108493 doi:10.1016/j.ymgme.2024.108493.

    PMID: 38772327
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    Allelic prevalence and geographic distribution of cerebrotendinous xanthomatosis.

    Pramparo T, Steiner RD, Rodems S, Jenkinson C

    Orphanet journal of rare diseases 2023; (18(1)):13 doi:10.1186/s13023-022-02578-1.

    PMID: 36650582
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    Case Report: a novel CYP27A1 gene variant in a patient with cerebrotendinous xanthomatosis with unusual clinical findings.

    Tama Viteri FA, Cotán Marín D, Sánchez FAT, Sánchez MAT

    The International journal of neuroscience 2025; (135(3)):358-366 doi:10.1080/00207454.2023.2300735.

    PMID: 38153323
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    Apparent underdiagnosis of Cerebrotendinous Xanthomatosis revealed by analysis of ~60,000 human exomes.

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    Molecular genetics and metabolism 2015; (116(4)):298-304.

    PMID: 26643207
  14. 14

    Cerebrotendinous Xanthomatosis occurs at high frequency in Ashkenazi Jews.

    Hanson J, Bonnen PE

    Molecular genetics and metabolism 2025; (144(3)):109041 doi:10.1016/j.ymgme.2025.109041.

    PMID: 39874852
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    Update on cerebrotendinous xanthomatosis.

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    Current opinion in lipidology 2021; (32(2)):123-131 doi:10.1097/MOL.0000000000000740.

    PMID: 33630770
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    Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review.

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    Brain sciences 2023; (13(7)) doi:10.3390/brainsci13070979.

    PMID: 37508912
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    Cerebrotendinous xanthomatosis: A rare neurodegenerative disorder with characteristic imaging findings.

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    Differing clinical features between Japanese siblings with cerebrotendinous xanthomatosis with a novel compound heterozygous CYP27A1 mutation: a case report.

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    A Novel Compound Heterozygous CYP27A1 Variant in Cerebrotendinous Xanthomatosis: A Case Report from a Non-Consanguineous Family.

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This page provides general educational information about a cerebrotendinous xanthomatosis (CTX) diagnosis. Always consult your metabolic specialist or geneticist for personalized medical advice, testing, and treatment plans.

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