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CYP27B1 gene
URL of this page: https://medlineplus.gov/genetics/gene/cyp27b1/

CYP27B1 gene

cytochrome P450 family 27 subfamily B member 1

Normal Function

The CYP27B1 gene provides instructions for making an enzyme that is part of the cytochrome P450 family of enzymes. Cytochrome P450 enzymes are involved in the activation or breakdown (metabolism) of many medications and hormones, and they help produce cholesterol, certain hormones, and fats (lipids).

The CYP27B1 enzyme is found in the mitochondria, which are the energy-producing centers of cells. This enzyme carries out the second of two reactions that are required to convert vitamin D to its active form, which is called calcitriol. Vitamin D can be obtained from food or made in the skin after exposure to the sun or to light from certain other sources, such as tanning beds. When active, vitamin D helps maintain the proper balance of calcium and phosphate in the blood. These minerals strengthen bones and teeth and allow them to develop normally. One of vitamin D's major roles is to help regulate the absorption of calcium and phosphate from the intestines into the bloodstream.

Health Conditions Related to Genetic Changes

Vitamin D-dependent rickets

Genetic changes that cause disease are called pathogenic variants. Pathogenic variants in the CYP27B1 gene have been found to cause a specific form of vitamin D deficiency called vitamin D-dependent rickets type 1A (VDDR1A). This disorder is caused by soft, weak bones (rickets) that are prone to fracture and more likely to be misshapen. A common feature of this condition is abnormally curved (bowed) legs, but affected individuals may also have enlargement of the skull, the wrists, and the ends of the ribs.

Pathogenic variants in the CYP27B1 gene cause cells to produce a version of the enzyme that does not function properly. This disrupts the conversion of vitamin D to calcitriol, which impairs the intestinal absorption of calcium and phosphate. Decreased blood levels of calcium and phosphate lead to the weakened bones that are seen in affected individuals.

More About This Health Condition

Other Names for This Gene

  • 1alpha(OH)ase
  • 25-Hydroxyvitamin D3 1alpha-hydroxylase
  • Calcidiol 1-monooxygenase
  • CYP1
  • P450c1
  • VDDR I

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

References

  • Demir K, Kattan WE, Zou M, Durmaz E, BinEssa H, Nalbantoglu O, Al-Rijjal RA, Meyer B, Ozkan B, Shi Y. Novel CYP27B1 Gene Mutations in Patients with Vitamin D-Dependent Rickets Type 1A. PLoS One. 2015 Jul 1;10(7):e0131376. doi: 10.1371/journal.pone.0131376. eCollection 2015. Citation on PubMed or Free article on PubMed Central
  • Durmaz E, Zou M, Al-Rijjal RA, Bircan I, Akcurin S, Meyer B, Shi Y. Clinical and genetic analysis of patients with vitamin D-dependent rickets type 1A. Clin Endocrinol (Oxf). 2012 Sep;77(3):363-9. doi: 10.1111/j.1365-2265.2012.04394.x. Citation on PubMed
  • Gentile C, Chiarelli F. Rickets in Children: An Update. Biomedicines. 2021 Jun 27;9(7):738. doi: 10.3390/biomedicines9070738. Citation on PubMed
  • Kim CJ, Kaplan LE, Perwad F, Huang N, Sharma A, Choi Y, Miller WL, Portale AA. Vitamin D 1alpha-hydroxylase gene mutations in patients with 1alpha-hydroxylase deficiency. J Clin Endocrinol Metab. 2007 Aug;92(8):3177-82. doi: 10.1210/jc.2006-2664. Epub 2007 May 8. Citation on PubMed
  • Levine MA. Diagnosis and Management of Vitamin D Dependent Rickets. Front Pediatr. 2020 Jun 12;8:315. doi: 10.3389/fped.2020.00315. eCollection 2020. Citation on PubMed
  • Malloy PJ, Feldman D. Genetic disorders and defects in vitamin D action. Rheum Dis Clin North Am. 2012 Feb;38(1):93-106. doi: 10.1016/j.rdc.2012.03.009. Epub 2012 Apr 12. Citation on PubMed
  • Nebert DW, Wikvall K, Miller WL. Human cytochromes P450 in health and disease. Philos Trans R Soc Lond B Biol Sci. 2013 Jan 6;368(1612):20120431. doi: 10.1098/rstb.2012.0431. Print 2013 Feb 19. Citation on PubMed or Free article on PubMed Central
  • Portale AA, Miller WL. Human 25-hydroxyvitamin D-1alpha-hydroxylase: cloning, mutations, and gene expression. Pediatr Nephrol. 2000 Jul;14(7):620-5. doi: 10.1007/pl00009639. Citation on PubMed
  • Ryan JW, Anderson PH, Turner AG, Morris HA. Vitamin D activities and metabolic bone disease. Clin Chim Acta. 2013 Oct 21;425:148-52. doi: 10.1016/j.cca.2013.07.024. Epub 2013 Jul 30. Citation on PubMed

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