Molecular Genetic and Bile Acid Profiles in Two Japanese Patients With 3β-Hydroxy-Δ5-C27-Steroid Dehydrogenase/Isomerase Deficiency

Abstract

ABSTRACT:We report definitive diagnosis and effective chenodeoxycholic acid (CDCA) treatment of two Japanese children with 3␤-hydroxy-⌬ 5 -C 27 -steroid dehydrogenase/isomerase deficiency. Findings of cholestasis with normal serum ␥-glutamyltransferase activity and total bile acid concentration indicated the need for definitive bile acid analysis. Large amounts of 3␤-hydroxy-⌬ 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␤-hydroxy-⌬ 5 -bile acids such as 3␤,7␣-dihydroxy-and 3␤,7␣,12␣-trihydroxy-5-cholenoic acids were detected in the first patient's urine; the second patient's urine contained large amounts of 3␤-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␤-hydroxy-⌬ 5 -C 27 -steroid dehydrogenase/isomerase deficiency. Early neonatal diagnosis permits initiation of CDCA treatment at this critical time, before the late cholestatic stage. (Pediatr Res 68: 258-263, 2010) D eficiency of 3␤-hydroxy-⌬ 5 -C 27 -steroid dehydrogenase/ isomerase (3␤-HSD) was first described by Clayton et al. in 1987 (1). This inborn error of bile acid synthesis is very rare and shows autosomal recessive inheritance. The main findings in 3␤-HSD deficiency are low or normal concentrations of total bile acid and normal activity of ␥-glutamyltransferase (GGT) in serum, as well as absence of pruritus despite conjugated hyperbilirubinemia, elevated alanine aminotransferase (ALT), and fatty stools. In the synthesis of bile acids from cholesterol, 3␤-HSD catalyzes the second of a series of reactions leading to excretion of 3␤,7␣-dihydroxy-5-cholenoic acid (⌬ 5 -3␤,7␣-diol) and 3␤,7␣,12␣-trihydroxy-5-cholenoic acid (⌬ 5 -3␤,7␣,12␣-triol) in the urine. In the first reported patient, complete absence of 3␤-HSD activity was found by Buchmann et al. in 1990 (2) based on the study of cultured fibroblasts. In 2000, Schwarz et al. (3) reported that the same patient had a homozygous mutation representing a 2-bp deletion in exon 6 of the 3␤-HSD gene (HSD3B7) on chromosome 16p11.2-12. The human HSD3B7 gene contains six coding exons and encodes 369 amino acids; so far, 13 distinct mutations causing 3␤-HSD deficiency have been reported (4,5).Here, we report genetic analyses of two Japanese patients with 3␤-HSD deficiency: one previously reported patient (6,7) was diagnosed with 3␤-HSD deficiency by bile acid analysis and the ot...

Use of dried urine spots for screening of inborn errors of bile acid synthesis

“…As seen in our previous case reports, in the present study higher proportions of the unusual BA were detected than of the usual BA. For example, there were high levels of Δ 5 ‐diol‐ and Δ 5 ‐triol‐BA in the 3β‐HSD samples, of Δ 5 ‐ol BA in the oxysterol 7α‐deficiency samples, and of Δ 4 ‐BA in the 5β‐reductase deficiency samples . Patient 1 was lost to follow up; similarly, the prognosis of patient 2 is unknown, because no further medical records were obtained from his doctor.…”

Evaluation of the pediatric patient for liver transplantation: 2014 practice guideline by the american association for the study of liver diseases, american society of transplantation and the north american society for pediatric gastroenterology, hepatolo

“…Unlike most cholestatic diseases, patients with inborn errors of bile acid synthesis generally present with the hallmark features of normal or low serum levels of primary bile acids, normal GGT concentrations, and the absence of pruritus . For a definitive diagnosis, fast atom bombardment‐mass spectrometry (FAB‐MS) and gas chromatography‐mass spectrometry (GC‐MS) analyses of serum and urine is recommended, but is only available in a few specialized referral laboratories . Early diagnosis of some defects of bile acid synthesis can be treated effectively with cholic acid and/or chenodeoxycholic acid, which down‐regulate endogenous bile acid synthesis resulting in clinical, biochemical, and histologic improvement if therapy is initiated before significant liver disease is established .…”

Prognostic roles of tetrahydroxy bile acids in infantile intrahepatic cholestasis

“…The urine samples were analyzed by GC-MS as previously described (8,18,19). Urine BA concentrations were corrected for the creatinine (Cre) concentration and expressed as micromoles per millimole of Cre.…”