Normal Function
The HSD3B7 gene provides instructions for making an enzyme called 3 beta-hydroxysteroid dehydrogenase type 7 (3β-HSD7). This enzyme is found in liver cells. It is embedded in the membrane of a cell structure called the endoplasmic reticulum, which is involved in protein processing and distribution. The 3β-HSD7 enzyme participates in the production of bile acids, which are a component of a digestive fluid called bile. Bile acids stimulate bile flow and helps absorb fats and fat-soluble vitamins. Bile acids are produced from cholesterol in a multi-step process. The 3β-HSD7 enzyme is responsible for the second step in that process, which converts 7alpha(α)-hydroxycholesterol to 7α-hydroxy-4-cholesten-3-one.
Health Conditions Related to Genetic Changes
Congenital bile acid synthesis defect type 1
At least 17 mutations in the HSD3B7 gene have been found to cause congenital bile acid synthesis defect type 1. This condition is characterized by cholestasis, a condition that impairs the production and release of a digestive fluid called bile from liver cells. Most of the HSD3B7 gene mutations delete one or two DNA building blocks (base pairs) from the gene or replace single protein building blocks (amino acids) in the enzyme. These mutations result in production of a 3β-HSD7 enzyme with little or no function. Without enough functional 3β-HSD7 enzyme, the conversion of 7α-hydroxycholesterol to 7α-hydroxy-4-cholesten-3-one is impaired. The 7α-hydroxycholesterol instead gets converted into abnormal bile acid compounds that cannot be transported out of the liver into the intestine, where the bile acids are needed to absorb fats and fat-soluble vitamins. This impaired production and release of bile acids leads to cholestasis. As a result, cholesterol and abnormal bile acids build up in the liver and fat-soluble vitamins are not absorbed, leading to the signs and symptoms of congenital bile acid synthesis defect type 1.
More About This Health ConditionOther Names for This Gene
- 3 beta-hydroxy-delta 5-C27-steroid oxidoreductase
- 3 beta-hydroxysteroid dehydrogenase type 7
- 3 beta-hydroxysteroid dehydrogenase type VII
- 3-beta-HSD VII
- 3-beta-hydroxy-Delta(5)-C27 steroid oxidoreductase
- 3BHS7_HUMAN
- c(27) 3-beta-HSD
- C(27)-3BETA-HSD
- cholest-5-ene-3-beta,7-alpha-diol 3-beta-dehydrogenase
- SDR11E3
- short chain dehydrogenase/reductase family 11E, member 3
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Cheng JB, Jacquemin E, Gerhardt M, Nazer H, Cresteil D, Heubi JE, Setchell KD, Russell DW. Molecular genetics of 3beta-hydroxy-Delta5-C27-steroid oxidoreductase deficiency in 16 patients with loss of bile acid synthesis and liver disease. J Clin Endocrinol Metab. 2003 Apr;88(4):1833-41. doi: 10.1210/jc.2002-021580. Citation on PubMed
- Gioiello A, Cerra B, Zhang W, Vallerini GP, Costantino G, De Franco F, Passeri D, Pellicciari R, Setchell KD. Synthesis of atypical bile acids for use as investigative tools for the genetic defect of 3beta-hydroxy-Delta(5)-C27-steroid oxidoreductase deficiency. J Steroid Biochem Mol Biol. 2014 Oct;144 Pt B:348-60. doi: 10.1016/j.jsbmb.2014.06.008. Epub 2014 Jun 19. Citation on PubMed
- Subramaniam P, Clayton PT, Portmann BC, Mieli-Vergani G, Hadzic N. Variable clinical spectrum of the most common inborn error of bile acid metabolism--3beta-hydroxy-Delta 5-C27-steroid dehydrogenase deficiency. J Pediatr Gastroenterol Nutr. 2010 Jan;50(1):61-6. doi: 10.1097/MPG.0b013e3181b47b34. Citation on PubMed
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