3-beta-hydroxy-delta-5-c27-steroid oxidoreductase deficiency type 1 is a very rare inherited disease of bile acid making. It happens when the body cannot properly do one important step in the normal pathway that turns cholesterol into bile acids inside the liver. Because of that block, the liver makes too little normal bile acid and too much abnormal bile acid-like material. These abnormal substances can build up and damage the liver. This disease is also called a congenital bile acid synthesis defect, and it often starts in early life, especially with jaundice or cholestasis in babies, although later presentation can also happen. [1]
3-beta-hydroxy-delta-5-c27-steroid oxidoreductase deficiency type 1 is also called congenital bile acid synthesis defect type 1, HSD3B7 deficiency, and 3β-hydroxy-Δ5-C27-steroid oxidoreductase deficiency. It is a very rare inherited liver disease. The body cannot make normal primary bile acids well, so toxic abnormal bile acids build up, bile flow becomes poor, fat is not absorbed well, and vitamins A, D, E, and K can become low. Many babies develop jaundice, poor growth, pale stools, bleeding, or liver injury, but some people present later with chronic liver disease. The good news is that this is one of the rare liver disorders that can improve a lot when it is found early and treated correctly.
This disease happens because the HSD3B7 gene does not work properly. That gene helps the liver make normal bile acids from cholesterol. Normal bile acids are needed to move bile out of the liver and to absorb fats and fat-soluble vitamins from food. When the enzyme is missing, the body makes unusual bile acid chemicals instead of the normal ones. These abnormal chemicals can injure the liver, and the lack of normal bile acids can cause malnutrition, diarrhea or fatty stool, weak growth, bleeding from vitamin K deficiency, and later scarring of the liver.
In very simple words, bile acids are natural chemicals made by the liver. They help bile move, help the body digest fat, and help the body absorb vitamins A, D, E, and K. In this disease, the liver cannot make enough of the normal bile acids that it needs. At the same time, unusual toxic intermediates may accumulate. That is why the child or adult can develop yellow eyes, pale stools, poor growth, vitamin deficiency, bleeding problems, or liver disease. The good news is that this disorder is considered treatable when doctors recognize it early and start proper bile acid replacement therapy. [2]
Another names
Other names used for this condition include congenital bile acid synthesis defect type 1, congenital bile acid synthesis disorder type 1, CBAS1, HSD3B7 deficiency, 3β-hydroxy-Δ5-C27-steroid oxidoreductase deficiency, and 3β-hydroxy-Δ5-C27-steroid dehydrogenase/isomerase deficiency. Different papers and databases may use slightly different spelling, but they refer to the same basic disease caused by disease-causing changes in the HSD3B7 gene. [3]
Types
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Neonatal or infantile type: symptoms begin in the first weeks or months of life, often with jaundice and cholestasis. [4]
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Childhood-onset type: symptoms appear later, often with growth problems, vitamin deficiency, or chronic liver disease. [5]
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Adult-onset type: a small number of people are diagnosed much later, sometimes after cirrhosis or long unexplained liver disease. [6]
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Mild type: some people have less severe early symptoms but still need diagnosis and treatment. [7]
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Severe progressive liver type: some people develop fibrosis, cirrhosis, or liver failure if untreated. [8]
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Fat-soluble-vitamin deficiency dominant type: some patients show major problems from low vitamins A, D, E, or K. [9]
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Cholestatic presentation type: the main problem is poor bile flow and jaundice. [10]
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Cirrhosis-presenting type: in rare cases, the first major sign is advanced liver scarring. [11]
Causes
The true basic cause of this disease is not 20 different diseases. The real cause is one main problem: a person inherits harmful changes in both copies of the HSD3B7 gene, usually one from each parent. Below are 20 simple cause statements that explain the genetic and family patterns that can lead to this disorder or explain why it appears in a child. [12]
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A disease-causing mutation in one HSD3B7 copy from the mother and one disease-causing mutation in the other copy from the father can cause the disorder. This is the usual autosomal recessive pattern. [13]
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Homozygous mutation means the same harmful HSD3B7 variant is inherited from both parents. This can happen more often in related parents or in small communities. [14]
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Compound heterozygous mutation means two different harmful HSD3B7 variants are inherited, one on each gene copy. This is also a common way the disease appears. [15]
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Small deletion mutations can remove one or more DNA letters from HSD3B7 and stop the enzyme from working normally. [16]
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Small insertion mutations can add extra DNA letters and disturb the reading frame of the gene, leading to a defective enzyme. [17]
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Frameshift mutations can badly alter the protein after the change point and often produce a very short or nonworking enzyme. [18]
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Nonsense mutations can create a premature stop signal, so the body makes an incomplete enzyme. [19]
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Missense mutations can change one amino acid in the enzyme and reduce how well it works. [20]
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Splice-site mutations can disrupt how the RNA is cut and joined, leading to an abnormal enzyme message. [21]
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Loss-of-function variants are a broad group of gene changes that lower or remove enzyme activity and cause the biochemical block. [22]
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Inheritance from two healthy carrier parents can cause disease in the child even when the parents have no symptoms. [23]
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Family history of the same disorder raises the chance that a newborn with jaundice may have this condition. [24]
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Consanguinity, meaning parents are blood relatives, can increase the chance that both carry the same rare HSD3B7 variant. [25]
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Rare founder variants in some families or populations may lead to repeated cases in that family line. [26]
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Severe variants that almost fully stop enzyme activity may cause earlier and more serious disease. [27]
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Milder variants that leave some enzyme activity may lead to later diagnosis or slower disease progression. [28]
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Failure of the HSD3B7 enzyme to convert the 3β-hydroxy-Δ5 bile acid intermediate is the direct biochemical cause of the disease process. [29]
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Reduced normal primary bile acid production is another immediate cause of symptoms because bile flow and fat absorption become poor. [30]
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Build-up of atypical 3β-hydroxy-Δ5 bile acids contributes to liver injury and cholestasis. [31]
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Delayed recognition does not cause the gene defect, but it can cause the disease to become much worse because toxic metabolites stay present longer. [32]
Symptoms
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Jaundice is one of the most common symptoms. The skin and eyes look yellow because bilirubin builds up when bile flow is poor. [33]
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Cholestasis means bile is not made or released properly. This is the central clinical problem in many patients with this disease. [34]
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Pale or clay-colored stools can happen because less bile pigment reaches the intestine. [35]
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Dark urine may appear because bilirubin products pass out through the kidneys. [36]
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Poor weight gain can happen because fat digestion is weak and the child does not absorb enough calories. [37]
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Failure to thrive means the baby grows more slowly than expected. This can happen when liver disease and poor absorption continue for a long time. [38]
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Diarrhea or greasy stools may occur because the body cannot absorb dietary fat well without normal bile acids. [39]
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Bleeding tendency can happen from vitamin K deficiency, because vitamin K needs fat absorption to enter the body well. [40]
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Easy bruising can occur for the same reason, especially when vitamin K stores are low. [41]
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Enlarged liver, also called hepatomegaly, may be found because the liver is under stress and becomes inflamed or scarred. [42]
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Enlarged spleen can appear later if chronic liver disease and portal pressure increase. [43]
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Itching may happen in some cholestatic patients, although it is not always the main symptom in bile acid synthesis defects. [44]
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Rickets or weak bones may develop because vitamin D absorption is poor over time. [45]
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Night vision or eye problems may happen if vitamin A deficiency becomes important. [46]
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Cirrhosis or liver failure symptoms can appear in untreated patients, especially when diagnosis is late. [47]
Diagnostic tests
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Physical examination is the starting point. The doctor looks for jaundice, poor growth, dehydration, belly swelling, bruises, and general illness. This test does not confirm the disease, but it tells the doctor that a liver or metabolic problem may be present. [48]
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Skin and sclera inspection is a simple bedside check. Yellow skin and yellow eyes strongly suggest bilirubin build-up and cholestasis. [49]
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Growth assessment is important in babies and children. Doctors measure weight, length, and head growth because poor fat absorption and chronic liver disease can slow normal growth. [50]
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Abdominal palpation is a manual test in which the doctor gently feels the belly to check for enlarged liver, enlarged spleen, or fluid build-up. [51]
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Stool color review is a practical clinical test. Parents may report pale stools, which helps doctors think about cholestatic disease. [52]
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Liver function blood tests are very important. Doctors check bilirubin, AST, ALT, and related markers to measure liver injury and cholestasis. [53]
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Serum gamma-glutamyl transferase, often called GGT, is useful because some bile acid synthesis disorders show cholestasis with normal or relatively low GGT, which can be a clue. [54]
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Total serum bile acid testing may be done, but in this disorder normal or low-normal bile acid levels do not rule the disease out. That is why special bile acid profiling is more useful. [55]
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Coagulation studies such as PT and INR help detect vitamin K deficiency and liver-related clotting problems. They matter because some children bleed easily. [56]
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Fat-soluble vitamin level testing checks vitamins A, D, E, and K status. These levels may become low because fat absorption is poor. [57]
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Serum cholesterol can be measured because some patients have low cholesterol in association with the disorder. [58]
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Urine bile acid analysis by mass spectrometry is one of the key diagnostic tests. It looks for unusual 3β-hydroxy-Δ5 bile acid metabolites, which are strongly suggestive of HSD3B7 deficiency. [59]
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Fast atom bombardment mass spectrometry, often written FAB-MS, has been used in urine testing to identify the special abnormal bile acid pattern in this disease. [60]
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Liquid chromatography–mass spectrometry can also help detect abnormal bile acid intermediates with high sensitivity. [61]
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Genetic testing of the HSD3B7 gene is a confirmatory test. It can identify the exact disease-causing variants and prove the diagnosis. [62]
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Family genetic testing may be offered after diagnosis. It helps identify carriers, explains recurrence risk, and can guide future pregnancy planning. [63]
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Liver biopsy is a pathological test that may be used when diagnosis is unclear. It can show cholestatic liver injury, giant cell change, fibrosis, or cirrhosis, but it is not as specific as bile acid profiling plus genetic testing. [64]
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Liver ultrasound is an imaging test used to look at liver size, texture, bile ducts, spleen size, and other structural causes of cholestasis. It helps rule out more common problems such as biliary obstruction. [65]
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Transient elastography or other fibrosis assessment may be used in some centers to estimate liver stiffness and follow chronic liver damage over time. [66]
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There is no standard electrodiagnostic test that diagnoses this disease directly. In practice, the most useful “electrodiagnostic-like” category is advanced instrument-based metabolic testing by mass spectrometry, while imaging and genetic testing provide the main confirmation. This is important to say clearly so the reader is not misled. [67]
Non-pharmacological treatments
The most important non-drug treatment is close follow-up with a pediatric liver or metabolic specialist. This helps doctors adjust bile acid therapy, nutrition, vitamins, and blood tests before liver damage becomes severe. Regular growth monitoring is also important because poor weight gain may be the first sign that treatment is not enough. Dietitian-guided feeding plans help families give enough calories and protein for growth. Small frequent meals can reduce feeding stress and improve intake in infants with poor appetite.
Fat-soluble vitamin monitoring, stool and feeding review, hydration support, and careful symptom diaries are also useful. These steps do not fix the gene problem, but they help doctors see whether malabsorption, diarrhea, bleeding risk, or cholestasis is improving. Parents often notice changes in jaundice, stool color, bruising, itching, or poor feeding before laboratory values are repeated.
Nutrition therapy is a major part of care. Many children need high-calorie feeding plans, better protein intake, and sometimes tube feeding if growth is poor. Breast milk or formula support, feeding therapy, swallow assessment when needed, and night feeds in weak infants are supportive methods that help growth while the main medical treatment starts working. The purpose is to prevent malnutrition and support brain and body development.
Liver blood test monitoring, coagulation monitoring, ultrasound follow-up, and urine bile acid testing when available are also core parts of non-drug care. These are not medicines, but they guide treatment and help doctors catch worsening liver disease, cirrhosis, portal hypertension, or persistent abnormal bile acid production early.
Other supportive approaches include infection prevention, vaccination follow-up, easy bruise and bleed precautions, physical activity as tolerated, avoidance of alcohol later in life, avoidance of unnecessary liver-toxic products, family genetic counseling, and planning future pregnancies with carrier testing. These steps reduce extra stress on the liver and help families understand recurrence risk.
Drug treatments
There is an important limit in the evidence: there is only one FDA-approved disease-specific drug for this condition, and that is cholic acid. So a true list of 20 proven drugs that directly treat the enzyme defect does not exist. The medicines below include the main disease-specific therapy plus supportive drugs used for complications such as vitamin deficiency, malabsorption, edema, or advanced liver disease. Only some of these have FDA labeling on [accessdata] and only cholic acid directly treats the root bile acid problem.
1. Cholic acid (CHOLBAM) is the key treatment. It replaces missing primary bile acid, suppresses production of toxic abnormal bile acids, improves bile flow, and can improve liver tests, growth, and survival when started early. The FDA label recommends 10 to 15 mg/kg/day orally once daily or in two divided doses. Common side effects listed include diarrhea, reflux, malaise, jaundice changes, skin lesions, nausea, abdominal pain, and liver test abnormalities. It is the most important medicine for this disease.
2. Chenodeoxycholic acid has been used in published cases and series when specialist teams judged it appropriate. It may help replace deficient primary bile acids and reduce toxic intermediates, but it is not the FDA-approved standard product for this disease in the United States. Dose plans vary by specialist and patient size, so it must be individualized. It can cause diarrhea and liver-related adverse effects if not monitored carefully.
3. Phytonadione (vitamin K1, AquaMEPHYTON) is used when vitamin K deficiency or bleeding risk develops because cholestasis reduces vitamin absorption. It helps the liver make clotting factors. The FDA label supports use for states of vitamin K deficiency and hypoprothrombinemia. Dose and route depend on age and severity, often guided by INR and bleeding status. Side effects can include injection reactions and, rarely, hypersensitivity.
4. Vitamin A replacement, 5. vitamin D replacement, and 6. vitamin E replacement are often needed because this disease causes poor absorption of fat-soluble vitamins. These do not correct the gene defect, but they protect vision, bones, nerves, immunity, and growth. Doses are individualized using blood levels, age, and clinical signs. Too much can also be harmful, especially vitamins A and D, so monitoring matters.
7. Multivitamin preparations for cholestasis may be used when several vitamins are low together. Their purpose is broad nutritional replacement. 8. Calcium may be added when bone health is poor. 9. Zinc may help if deficiency is present due to malabsorption or poor intake. 10. Iron may be needed if chronic disease or nutritional deficiency causes anemia. These are supportive, not curative.
11. Ursodiol (ursodeoxycholic acid) has sometimes been used in cholestatic liver disease, but it is not the core disease-specific therapy for HSD3B7 deficiency and should not replace cholic acid when true bile acid synthesis defect type 1 is confirmed. It may improve bile flow in some cholestatic settings, but specialist judgment is needed because bile acid replacement with primary bile acids is the central treatment concept here.
12. Pancreatic enzyme products such as pancrelipase may be considered only if a patient has separate pancreatic insufficiency or major fat digestion problems from another cause; they are not standard treatment for the enzyme defect itself. 13. Albumin infusion may be used in hospital for severe low albumin states. 14. Lactulose may be used if liver failure leads to encephalopathy. 15. Rifaximin may be added in the same setting. These treat complications, not the inherited bile acid defect.
16. Furosemide and 17. spironolactone may be used when advanced liver disease causes edema or ascites. FDA labels support their use for edema states, including cirrhosis-related fluid retention. Dosing is individualized by age, kidney function, and electrolyte status. Side effects include dehydration, low sodium, low potassium with furosemide, and high potassium or breast swelling with spironolactone.
18. Antibiotics for cholangitis or infection, 19. proton pump inhibitors for reflux or stress-related upper gut symptoms, and 20. pain or fever medicines chosen carefully for liver disease may be used when needed. These are supportive treatments around the main disease. In simple words, for this disorder the drug story is clear: cholic acid is the real targeted treatment; most other medicines are for complications or nutrition support.
Dietary molecular supplements
The best-supported supplements are the ones that replace nutrients lost because of fat malabsorption. Vitamin A, vitamin D, vitamin E, and vitamin K are the main four. Their function is to restore vision and immunity, bone and calcium balance, nerve and cell membrane protection, and normal blood clotting. Doses must be individualized by a clinician because both deficiency and overdose can be dangerous.
Other useful dietary supports can include calcium, phosphorus support through diet, zinc, iron, selenium when low, and protein supplements for growth. In some children, medium-chain triglyceride support may help overall calorie intake, although the core disease problem is lack of normal bile acids rather than simple pancreatic fat digestion failure. These supports work by improving nutrition, growth, and deficiency states while primary bile acid treatment fixes the main pathway.
6 immunity booster, regenerative, or stem cell drugs
At present, there are no established immunity-booster drugs, stem cell drugs, or regenerative medicines that are proven standard treatment for HSD3B7 deficiency. This is important to say clearly. The disease is mainly treated by bile acid replacement, nutrition support, vitamins, and in severe late disease, liver transplantation. Claims of immune boosters or stem cell cures for this disorder are not supported by standard rare-disease guidance.
If a patient develops advanced liver disease, doctors may still use supportive biologic or intensive therapies for complications in hospital, but these are not regenerative cures for this metabolic defect. For SEO clarity and safety, the evidence-based answer is simple: no validated stem cell drug list exists for this disease today.
Surgeries or procedures
Liver transplantation is the main major procedure when diagnosis is late or when treatment fails and the liver has already reached severe failure or cirrhosis. It is done to replace the damaged liver and restore normal bile acid production by the donor liver.
Other procedures may include liver biopsy to assess damage, endoscopy for varices if portal hypertension develops, paracentesis for severe tense ascites, and feeding tube placement if severe malnutrition prevents normal growth. These procedures do not cure the genetic defect, but they can diagnose severity, control complications, or support nutrition.
Prevention tips
This disease itself is genetic, so it cannot be fully prevented after conception. But complications can often be prevented by early diagnosis, early cholic acid therapy, regular vitamin testing, good nutrition follow-up, growth monitoring, bleeding risk checks, avoiding delayed treatment, genetic counseling for parents, carrier testing in families, and care in a center familiar with metabolic liver disease.
When to see a doctor
See a doctor quickly if a baby or child has yellow eyes or skin, pale stool, dark urine, poor weight gain, easy bruising, bleeding, swollen belly, severe itching, repeated vomiting, confusion, or extreme tiredness. These can mean cholestasis, vitamin deficiency, or liver failure. In a known patient, worsening jaundice, new swelling, black stool, nosebleeds, poor feeding, or loss of growth are also warning signs.
Foods to eat and what to avoid
Helpful foods usually include age-appropriate high-calorie foods, good protein sources, doctor-approved vitamin-rich foods, fortified formula or feeds if needed, regular balanced meals, and enough fluids. The goal is to support growth and prevent malnutrition while medical treatment improves bile acid balance.
Foods or exposures to avoid can include alcohol later in life, unnecessary herbal products, unprescribed supplements, very poor-calorie diets, fasting for long periods in small children, and anything a liver specialist has flagged as harmful. Some patients also need caution with very fatty meals if digestion remains poor before treatment is optimized.
FAQs
What is this disease? It is a rare inherited bile acid production disorder. Is it genetic? Yes, usually autosomal recessive. Can it be treated? Yes, often with cholic acid and nutrition support. Is there a cure? The gene defect is not cured, but treatment can control disease well. Can babies improve? Yes, especially with early treatment.
Why are vitamins low? Because fat absorption is poor. Which vitamins are most important? A, D, E, and K. Why can bleeding happen? Vitamin K may become low. Why is growth poor? Fat and vitamins are not absorbed well. Can adults have it too? Yes, some cases present later.
Is cholic acid the main medicine? Yes. Are there 20 special FDA-approved drugs for this disease? No. Do stem cells cure it now? No proven standard therapy. Can liver transplant be needed? Yes, in severe advanced disease. Should family members get counseling? Yes, because future pregnancies may be affected.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: March 10, 2025.
