CYP27A1

Curated reports relevant to this gene

• Cerebrotendinous Xanthomatosis

  • Autosomal recessive

    Deficiency of sterol 27-hydroxylase causes chronic diarrhoea and cataracts in childhood, tendon xanthomas, and later ataxia, spasticity, cognitive decline and white matter changes.

    • ClinGen rates the link definitive
    • 6 GenCC submitters rate it definitive or strong

    What knowing changes

    Treatment with chenodeoxycholic acid can prevent or slow neurological disease, especially when started early.

Broader groupings

• Autosomal Recessive Cerebellar Ataxias (incl. CANVAS and AVED)

  • Autosomal Recessive Cerebellar AtaxiaAutosomal recessive

    One of 57 genes linked to it

    A group of recessively inherited ataxias caused by biallelic variants in genes such as RFC1, FXN, SACS, TTPA, SETX, APTX, PNKP, ANO10 and SYNE1.

    • ClinGen rates the link definitive
    • 6 GenCC submitters rate it definitive or strong

    What knowing changes

    Ataxia with vitamin E deficiency (TTPA) is treatable with vitamin E supplements; other forms are managed with physiotherapy and symptom care, and relatives can be offered carrier testing.

• Other Inherited Leukodystrophies

  • Leukodystrophy (other and unspecified types)

    One of 80 genes linked to it

    Inherited conditions that damage or prevent the normal formation of myelin, the white matter of the brain and spinal cord. Different types follow autosomal recessive, autosomal dominant or X-linked inheritance depending on the gene involved.

    • ClinGen rates the link definitive
    • 6 GenCC submitters rate it definitive or strong

    What knowing changes

    Knowing the specific genetic cause can end a diagnostic search, guide supportive care and surveillance, show whether a specific treatment exists, and allow testing of relatives.

• Lysosomal Storage Disease

  • Lysosomal storage disease (other and unspecified types)

    One of 59 genes linked to it

    Covers lysosomal storage diseases without a dedicated report, such as Farber disease and other ASAH1-related disorders, prosaposin (PSAP) deficiencies, multiple sulfatase deficiency, mucopolysaccharidosis types IX and X, and Dorfman-Chanarin disease; inheritance varies by subtype, most often autosomal recessive.

    • ClinGen rates the link definitive
    • 6 GenCC submitters rate it definitive or strong

How CYP27A1 is laid out

Exons make up 1.9 kb of the gene's 33.1 kb; 1,596 of those bases code for the protein.

How a genome test reads CYP27A1

Genes linked to the same conditions

• ARSAarylsulfatase AShares 2 conditions
• GALCgalactosylceramidaseShares 2 conditions
• PEX6peroxisomal biogenesis factor 6Shares 2 conditions
• PSAPprosaposinShares 2 conditions
• TPP1tripeptidyl peptidase 1Shares 2 conditions
• AARS1alanyl-tRNA synthetase 1Shares 1 condition
• AARS2alanyl-tRNA synthetase 2, mitochondrialShares 1 condition
• ABCD1ATP binding cassette subfamily D member 1Shares 1 condition
• ABHD5abhydrolase domain containing 5, lysophosphatidic acid acyltransferaseShares 1 condition
• ACER3alkaline ceramidase 3Shares 1 condition
• ADARadenosine deaminase RNA specificShares 1 condition
• AGAaspartylglucosaminidaseShares 1 condition

Traits linked to CYP27A1

The Human Phenotype Ontology lists these as features of the rare conditions CYP27A1 can cause. Each trait's page lists the other genes linked to it.

External links

Where this comes from

• HGNC: the gene's symbol, name, other symbols and location.
• MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
• GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
• The ACMG secondary findings list, SF v3.2.
• ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
• The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
• Data release 2026.10.16-c6eea6bf.

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