CYP2R1 encodes cytochrome P450 family 2 subfamily R member 1 (501 aa). A cytochrome P450 monooxygenase involved in activation of vitamin D precursors. Catalyzes hydroxylation at C-25 of both forms of vitamin D, vitamin D(2) and D(3) (calciol). Highest expression in Testis (22.9 TPM) and Skin Sun Exposed Lower leg (14.0 TPM).

Vitamin D hydroxylation-deficient rickets, type 1B is associated with mutations in the CYP2R1 gene on chromosome 11.

The CYP2R1 protein participates in CYP2R1 25-hydroxylates VD3 to 25(OH)D, Defective CYP2R1 does not 25-hydroxylate vitamin D, and VD3 translocates from extracellular region to ER membrane pathways.

CYP2R1 is classified as a druggable target (Cytochrome P450, Druggable Genome, and Enzyme categories) with score 4.4.

Genetic testing for CYP2R1 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 4 always present features.

2 clinical trials registered, 1 recruiting. Interventions under study include drug therapy and other interventions. Pipeline includes 2 NA. Research is primarily sponsored by academic and government institutions.

2 publications have been identified in PubMed for vitamin D hydroxylation-deficient rickets, type 1B. Research spans Review / Meta-Analysis (50%) and Epidemiology / Natural History (50%).

Recent Publications

• Zittermann A (2025). [PMID: 40565034](https://pubmed.ncbi.nlm.nih.gov/40565034/). *Int J Mol Sci*. [Review / Meta-Analysis]

• Iriani A (2024). [PMID: 38912300](https://pubmed.ncbi.nlm.nih.gov/38912300/). *Front Nutr*. [Epidemiology / Natural History]