3beta-hydroxy-delta5 -C27-steroid dehydrogenase deficiency: diagnosis and treatment

Bile Acid Synthesis Disorders in Arabs: A 10-year Screening Study

OBJECTIVES

Early diagnosis of bile acid synthesis disorders (BASDs) is important because, untreated, these conditions can be fatal. Our objectives were to screen children with cholestasis or unexplained liver disease for BASD and in those with confirmed BASD to evaluate the effectiveness of cholic acid therapy.

METHODS

A routine serum total bile acid measurement was performed on children with cholestasis, liver cirrhosis, and liver failure. Patients were screened for BASD by fast atom bombardment ionization-mass spectrometry (FAB-MS) analysis of urine, and molecular analysis confirmed diagnosis. Treatment response to oral cholic acid (10-15 mg/kg bw/day) was assessed from liver function tests and fat-soluble vitamin levels. FAB-MS analysis of urine was used to monitor compliance and biochemical response.

RESULTS

Between 2007 and 2016, 626 patients were evaluated; 450 with infantile cholestasis. Fifteen cases of BASD were diagnosed: 12 presented with infantile cholestasis (2.7%, 7 boys), an 8-year-old boy presented with cirrhosis, and two 18-month-old boys presented with hepatomegaly and rickets. Eleven were caused by 3β-hydroxy-Δ-C27-steroid oxidoreductase dehydrogenase deficiency, 3 from Δ-3-oxosteroid 5β-reductase deficiency, and 1 had Zellweger spectrum disorder. In all but 1, serum total bile acids were normal or low. With cholic acid therapy, 10 are alive and healthy with their native liver. Liver failure developed in 3 infants despite therapy; 2 died and 1 underwent liver transplantation.

CONCLUSIONS

BASDs are rare but treatable causes of metabolic liver disease in Saudi Arabia. BASD should be considered in infants with cholestasis and low or normal serum total bile acid concentrations.

Planar bile acids in health and disease

Bile acids are the amphipathic primary end-products of cholesterol metabolism that aid in digestion as well as participate in signal transduction in several hepatic and enteric pathways. Despite the reputation of bile acids as signaling molecules implicated in disease states such as cancer and diabetes, there remain numerous bile acid species that are weakly characterized in either physiological or pathological conditions. This review presents one such group: the flat or planar bile acids, a set of bile acids found in humans during infancy and occurring again during certain diseases. As their name implies, these molecules are structurally distinct from the typical human bile acids, retaining the planar structure of their cholesterol predecessor instead of bending or twisting at the A ring. This review defines these species of bile acids in detail and describes their presence in infancy, gestation, and in disease. The large gaps in research regarding the flat bile acids are highlighted and all available experimental knowledge collected as far as 60years ago is summarized. Further, the potential for these molecules as endogenous biomarkers of liver disease and injury is discussed. Finally, the flat bile salts found in humans are compared to the ancestral and evolutionary older bile salts, which similarly have a flat steroidal structure, as mechanisms of flat bile acid biosynthesis are explored.

Bile acid analysis in human disorders of bile acid biosynthesis

Bile acids facilitate the absorption of lipids in the gut, but are also needed to maintain cholesterol homeostasis, induce bile flow, excrete toxic substances and regulate energy metabolism by acting as signaling molecules. Bile acid biosynthesis is a complex process distributed across many cellular organelles and requires at least 17 enzymes in addition to different metabolite transport proteins to synthesize the two primary bile acids, cholic acid and chenodeoxycholic acid. Disorders of bile acid synthesis can present from the neonatal period to adulthood and have very diverse clinical symptoms ranging from cholestatic liver disease to neuropsychiatric symptoms and spastic paraplegias. This review describes the different bile acid synthesis pathways followed by a summary of the current knowledge on hereditary disorders of human bile acid biosynthesis with a special focus on diagnostic bile acid profiling using mass spectrometry.

Tandem Mass Spectrometric Determination of Atypical 3β-Hydroxy-Δ5-Bile Acids in Patients with 3β-Hydroxy-Δ5-C27-Steroid Oxidoreductase Deficiency: Application to Diagnosis and Monitoring of Bile Acid Therapeutic Response

BACKGROUND

3β-Hydroxy-Δ5-C27-steroid oxidoreductase (HSD3B7) deficiency, a progressive cholestatic liver disease, is the most common genetic defect in bile acid synthesis. Early diagnosis is important because patients respond to oral primary bile acid therapy, which targets the negative feedback regulation for bile acid synthesis to reduce the production of hepatotoxic 3β-hydroxy-Δ5-bile acids. These atypical bile acids are highly labile and difficult to accurately measure, yet a method for accurate determination of 3β-hydroxy-Δ5-bile acid sulfates is critical for dose titration and monitoring response to therapy.

METHODS

We describe a electrospray ionization LC-MS/MS method for the direct measurement of atypical 3β-hydroxy-Δ5-bile acid sulfates in urine from patients with HSD3B7 deficiency that overcomes the deficiencies of previously used GC-MS methods.

RESULTS

Separation of sulfated 3β-hydroxy-Δ5-bile acids was achieved by reversed-phase HPLC in a 12-min analytical run. The mean (SE) urinary concentration of the total 3β-sulfated-Δ5-cholenoic acids in patients with HSD3B7 deficiency was 4650 (1711) μmol/L, approximately 1000-fold higher than in noncholestatic and cholestatic patients with intact primary bile acid synthesis. GC-MS was not reliable for measuring 3β-hydroxy-Δ5-bile acid sulfates; however, direct analysis of urine by fast atom bombardment mass spectrometry yielded meaningful semiquantitative assessment of urinary excretion.

CONCLUSIONS

The tandem mass spectrometry method described here for the measurement of 3β-hydroxy-Δ5-bile acid sulfates in urine can be applied to the diagnosis and accurate monitoring of responses to primary bile acid therapy in HSD3B7 patients.

Two neonatal cholestasis patients with mutations in the SRD5B1 (AKR1D1) gene: diagnosis and bile acid profiles during chenodeoxycholic acid treatment

BACKGROUND AND AIMS

In two Japanese infants with neonatal cholestasis, 3-oxo-Δ(4)-steroid 5β-reductase deficiency was diagnosed based on mutations of the SRD5B1 gene. Unusual bile acids such as elevated 3-oxo-Δ(4) bile acids were detected in their serum and urine by gas chromatography-mass spectrometry. We studied effects of oral chenodeoxycholic acid treatment.

PATIENTS AND METHODS

SRD5B1 gene analysis used peripheral lymphocyte genomic DNA. Diagnosis and treatment of these two patients were investigated retrospectively and prospectively investigated.

RESULTS

With respect to SRD5B1, one patient was heterozygous (R266Q, a novel mutation) while the other was a compound heterozygote (G223E/R261C). Chenodeoxycholic acid treatment was effective in improving liver function and decreasing unusual bile acids such as 7α-hydroxy- and 7α,12α-dihydroxy-3-oxo-4-cholen-24-oic acids in serum and urine.

CONCLUSION

Primary bile acid treatment using chenodeoxycholic acid was effective for these patients treated in early infancy before the late stage of chronic cholestatic liver dysfunction.

Molecular genetic and bile acid profiles in two Japanese patients with 3beta-hydroxy-DELTA5-C27-steroid dehydrogenase/isomerase deficiency

We report definitive diagnosis and effective chenodeoxycholic acid (CDCA) treatment of two Japanese children with 3[beta]-hydroxy-[DELTA]5-C27-steroid dehydrogenase/isomerase deficiency. Findings of cholestasis with normal serum [gamma]-glutamyltransferase activity and total bile acid concentration indicated the need for definitive bile acid analysis. Large amounts of 3[beta]-hydroxy-[DELTA]5 bile acids were detected by gas chromatography-mass spectrometry. HSD3B7 gene analysis using peripheral lymphocyte genomic DNA from the patients and their parents identified four novel mutations of the HSD3B7 gene in the patients. One had a homozygous mutation, 314delA; the other had compound heterozygous mutations: V132F, T149I, and 973_974insCCTGC. Interestingly, the second patient's mother had V132F and T149I mutations in one allele. Excessive 3[beta]-hydroxy-[DELTA]5-bile acids such as 3[beta],7[alpha]-dihydroxy- and 3[beta],7[alpha],12[alpha]-trihydroxy-5-cholenoic acids were detected in the first patient's urine; the second patient's urine contained large amounts of 3[beta]-hydroxy-5-cholenoic acid. Liver dysfunction in both patients decreased with ursodeoxycholic acid treatment, but unusual bile acids were still detected. Normalization of the patients' liver function and improvement of bile acid profiles occurred with CDCA treatment. Thus, we found mutations in the HSD3B7 gene accounting for autosomal recessive neonatal cholestasis caused by 3[beta]-hydroxy-[DELTA]5-C27-steroid dehydrogenase/isomerase deficiency. Early neonatal diagnosis permits initiation of CDCA treatment at this critical time, before the late cholestatic stage.

Titration of bile acid supplements in 3beta-hydroxy-Delta 5-C27-steroid dehydrogenase/isomerase deficiency

OBJECTIVES

3beta-Hydroxy-Delta 5-C27-steroid dehydrogenase/isomerase deficiency is a bile acid synthesis defect responsive to primary bile acids. We reviewed its clinical features and response to treatment with a mixture of ursodeoxycholic (UDCA) and chenodeoxycholic acid (CDCA) to titrate the dose of supplements required for disease control.

PATIENTS AND METHODS

We studied our patients by liquid chromatography-tandem mass spectrometry, liver function tests, and histology. After diagnosis all of the patients received a balanced mixture of UDCA/CDCA and the dose was titrated according to urinary levels of 3beta,7 alpha-dihydroxy-5-cholenoic acid (u-3beta-D-OH-5C).

RESULTS

Five patients presenting with giant cell hepatitis, biliary cirrhosis, and cryptogenic cirrhosis (1 each), and picked up by neonatal screening (2 patients) were diagnosed at a median age of 2.5 years (range 0.1-5.5). Normal levels of u-3beta-D-OH-5C were achieved after 4 months (range 3-28 months) from the start of the treatment. The minimum dose of UDCA/CDCA required to maintain normal u-3beta-D-OH-5C levels was 5/5 mg x kg(-1) x day(-1). A follow-up biopsy in 2 patients showed no progression of liver disease.

CONCLUSIONS

A mixture of UDCA/CDCA can effectively control 3beta-hydroxy-Delta 5-C27-steroid dehydrogenase/isomerase deficiency. Dose titration by liquid chromatography-tandem mass spectrometry warrants the maintenance of negative feedback on the abnormal synthetic pathway and avoids disease progression.

Oral cholic acid for hereditary defects of primary bile acid synthesis: a safe and effective long-term therapy

BACKGROUND & AIMS

Oral bile acid replacement has been shown to be an effective therapy in primary bile acid synthesis defects, but to date there have been no reports of the long-term effects of this therapy. The aim of the study was to evaluate the long-term effectiveness and safety of cholic acid (CA) therapy.

METHODS

Fifteen patients with either 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase (3beta-HSD) (n = 13) or Delta(4)-3-oxosteroid 5beta-reductase (Delta(4)-3-oxo-R) (n = 2) deficiency confirmed by mass spectrometry and gene sequencing received oral CA and were followed up prospectively.

RESULTS

CA therapy was started at a median age of 3.9 years (range, 0.3-13.1 years). The median follow-up with treatment was 12.4 years (range, 5.6-15 years). The mean daily dose of CA was initially 13 mg/kg and was 6 mg/kg at last evaluation. During CA therapy, physical examination findings, laboratory test results, and findings on sonography normalized. Mass spectrometry analysis of urine showed that excretion of the atypical metabolites was reduced by 500-fold and 30-fold in 3beta-HSD and Delta(4)-3-oxo-R deficiency, respectively, and total urinary bile acid excretion decreased dramatically. Liver biopsies performed in 14 patients after at least 5 years of CA therapy showed marked improvement, especially in patients with the 3beta-HSD deficiency. CA was well tolerated with all children developing normally, including 2 women having 4 normal pregnancies during treatment.

CONCLUSIONS

Oral CA therapy is a safe and effective long-term treatment of the most common primary bile acid synthesis defects.

Mechanisms of disease: Inborn errors of bile acid synthesis

Inborn errors of bile acid synthesis are rare genetic disorders that can present as neonatal cholestasis, neurologic disease or fat-soluble-vitamin deficiencies. There are nine known defects of bile acid synthesis, including oxysterol 7alpha-hydroxylase deficiency, Delta(4)-3-oxosteroid-5beta-reductase deficiency, 3beta-hydroxy-Delta(5)-C(27)-steroid dehydrogenase deficiency, cerebrotendinous xanthomatosis (also known as sterol 27-hydroxylase deficiency), alpha-methylacyl-CoA racemase deficiency, and Zellweger syndrome (also known as cerebrohepatorenal syndrome). These diseases are characterized by a failure to produce normal bile acids and an accumulation of unusual bile acids and bile acid intermediaries. Individuals with inborn errors of bile acid synthesis generally present with the hallmark features of normal or low serum bile acid concentrations, normal gamma-glutamyl transpeptidase concentrations and the absence of pruritus. Failure to diagnose any of these conditions can result in liver failure or progressive chronic liver disease. If recognized early, many patients can have a remarkable clinical response to oral bile acid therapy.