Delta 4-3-oxosteroid 5 beta-reductase deficiency causing neonatal liver failure and hemochromatosis

Steroid 5β-reductase (AKR1D1): Purification and characterization

In mammals there are two 3-oxo-4-ene steroid reductases that generate either A/B-trans or A/B cis-ring junctions in the steroid nucleus known as steroid 5α- and 5β- reductases, respectively. There is only one steroid 5β- reductase in each species and these are members of the aldo-keto-reductase (AKR) protein superfamily. The corresponding human enzyme is AKR1D1, and it plays an essential role in bile-acid biosynthesis. Germline mutations in AKR1D1 give rise to bile-acid deficiency. Because of its central role in steroid metabolism and need for detailed structure-function studies there is a need to purify the enzyme to homogeneity and in high yield. We report the purification of milligram amounts of crystallographic quality homogeneous recombinant protein for structure-function studies and its characterization.

Extrahepatic Nonreticuloendothelial Siderosis Is Not Specific to Gestational Alloimmune Liver Disease

Autopsy reports of 78 stillbirths and early infant deaths (up to age 8 weeks) were reviewed to investigate the prevalence of extrahepatic nonreticuloendothelial siderosis (EHNRS) in the context of neonatal liver failure. Of these, 10 liveborns (12.8%), M:F 3:2, with mean gestational age 37.6 weeks (range: 35-39) and mean age at the time of demise 19.1 days (range: 7-42), showed significant liver injury: infection (n = 7, viral > fungal), congenital malformations (n = 2), and ischemia (n = 1). None had maternal history of gestational alloimmune liver disease (GALD) or previous fetal/neonatal death due to liver failure. Seven of 10 cases (70%) showed EHNRS: pancreas (n = 6), kidneys (n = 4), thyroid and adrenal glands (n = 3), and bronchial glands and heart (n = 2). Iron deposition was most frequent in the pancreas (60%), most diffuse in the kidneys, and seen in at least 2 organs, with pancreas and kidney being the most frequent combination. Hepatic C5b-9 expression was variable (1+ to 4+) except 1 case (100% necrosis). The duration of illness and the mean age at the time of demise tended to be higher in those with EHNRS. In summary, hepatic and EHNRS, with or without C5b-9 expression, are not specific for GALD. Other causes of liver failure should be investigated as clinically and pathologically appropriate.

Δ4-3-oxosteroid-5β-reductase deficiency: Responses to oral bile acid therapy and long-term outcomes

BACKGROUND

Disorders of primary bile acid synthesis may be life-threatening if undiagnosed, or not treated with primary bile acid replacement therapy. To date, there are few reports on the management and follow-up of patients with Δ4-3-oxosteroid 5β-reductase (AKR1D1) deficiency. We hypothesized that a retrospective analysis of the responses to oral bile acid replacement therapy with chenodeoxycholic acid (CDCA) in patients with this bile acid synthesis disorder will increase our understanding of the disease progression and permit evaluation of this treatment regimen as an alternative to the Food and Drug Administration (FDA) approved drug cholic acid, which is currently unavailable in China.

AIM

To evaluate the therapeutic responses of patients with AKR1D1 deficiency to oral bile acid therapy, specifically CDCA.

METHODS

Twelve patients with AKR1D1 deficiency, confirmed by fast atom bombardment ionization-mass spectrometry analysis of urine and by gene sequencing for mutations in AKR1D1, were treated with differing doses of CDCA or ursodeoxycholic acid (UDCA). The clinical and biochemical responses to therapy were monitored over a period ranging 0.5-6.4 years. Dose adjustment, to optimize the therapeutic dose, was based on changes in serum biochemistry parameters, notably liver function tests, and suppression of the urinary levels of atypical hepatotoxic 3-oxo-Δ4-bile acids measured by mass spectrometry.

RESULTS

Physical examination, serum biochemistry parameters, and sonographic findings improved in all 12 patients during bile acid therapy, except one who underwent liver transplantation. Urine bile acid analysis confirmed a significant reduction in atypical hepatotoxic 3-oxo-Δ4 bile acids concomitant with clinical and biochemical improvements in those patients treated with CDCA. UDCA was ineffective in down-regulating endogenous bile acid synthesis as evidenced from the inability to suppress the urinary excretion of atypical 3-oxo-Δ4-bile acids. The dose of CDCA required for optimal clinical and biochemical responses varied from 5.5-10 mg/kg per day among patients based on maximum suppression of the atypical bile acids and improvement in serum biochemistry parameters, and careful titration of the dose was necessary to avoid side effects from CDCA.

CONCLUSION

The primary bile acid CDCA is effective in treating AKR1D1 deficiency but the therapeutic dose requires individualized optimization. UDCA is not recommended for long-term management.

Prenatal imaging features suggestive of liver gestational allo immune disease

We report prenatal imaging features of four cases of neonatal hemochromatosis due to an alloimmune disease. All cases exhibited intra uterine growth restriction (IUGR) without arguments for a vascular etiology, associated with oligohydramnios. Placental hydrops was present in 75% of cases. Splenomegaly was identified in one case. Other causes of NH have been ruled out during diagnostic workup including karyotype, detection of IGFBP-1 to evaluate a premature rupture of membranes, maternal serologic tests. MRI was performed in two cases and showed an atrophic liver associated with a low signal intensity on T2-sequence in one case. Prenatal NH was suspected in this later case and the fetus was successfully treated with two IVIG (intravenous immunoglobulins) perfusions performed during pregnancy followed by exchange transfusion and IVIG after birth. The child is doing well with normal liver function tests after 17 months of follow up. Our aim was to highlight the importance of suggesting NH-GALD when facing IUGR with oligohydramnios, ascites, placental hydrops, splenomegaly on prenatal ultrasound with negative work up for placental vascular pathologies and infectious fetopathies. MRI might be of a good help, showing an atrophic liver but enhancing iron overload in hepatic and extrahepatic tissue is helpful but not constant.

Inborn Errors of Bile Acid Metabolism

Inborn errors of bile acid metabolism are rare causes of neonatal cholestasis and liver disease in older children and adults. The diagnosis should be considered in the context of hyperbilirubinemia with normal serum bile acids and made by urinary liquid secondary ionization mass spectrometry or DNA testing. Cholic acid is an effective treatment of most single-enzyme defects and patients with Zellweger spectrum disorder with liver disease.

Oral Cholic Acid Is Efficacious and Well Tolerated in Patients With Bile Acid Synthesis and Zellweger Spectrum Disorders

OBJECTIVES

Patients with bile acid synthesis disorders (BASDs) due to single enzyme defects (SEDs) or Zellweger spectrum disorders (ZSDs) accumulate hepatotoxic atypical bile acids resulting in potentially fatal progressive liver disease. We evaluated the efficacy and safety of oral cholic acid in patients with BASD.

METHODS

In this phase 3, open-label, single-arm, nonrandomized, noncomparative study conducted over 18 years, patients were administered cholic acid orally 10 to 15 mg · kg · day. The primary efficacy variables were changes from pre- to post-treatment in atypical urinary bile acids, liver chemistries (serum aspartate aminotransferase, alanine aminotransferase), and height and weight. Additional efficacy variables included changes in serum bilirubin and liver histology.

RESULTS

Of the 85 enrolled patients (63 with SED and 22 with ZSD), 79 received at least 1 dose of study medication; 70 patients (50 with SED and 20 with ZSD) were included in the modified intent-to-treat dataset. Cholic acid significantly improved urine bile acid metabolite scores (P < 0.0001) and serum aspartate aminotransferase and alanine aminotransferase (P < 0.0001) in patients with SED and ZSD. Cholic acid also improved height and weight percentiles in both groups, but only the change in weight was significant (P < 0.05). Serum direct bilirubin decreased significantly post-treatment (P < 0.001) in the intent-to-treat population, and liver biopsies showed either stable findings or histologic improvement in all parameters except bridging fibrosis. The overall safety profile of cholic acid was favorable, with no study drug-related serious adverse events or drug-related deaths reported.

CONCLUSIONS

Oral cholic acid is a safe, efficacious, and well-tolerated treatment for BASD due to SED and ZSD.

[Clinical feature and genetic analysis of a family affected by congenital bile acid synthesis defect type 2: identification of 2 novel mutations in AKR1D1 gene]

Congenital bile acid synthesis defect type 2 (CBAS2) is an autosomal recessive disorder caused by biallelic mutations of AKR1D1 gene, which encodes the Δ4-3-oxo-steroid 5β-reductase. Cholestatic jaundice is the main clinical manifestation, accompanied by malabsorption of fat and fat-soluble vitamins. This paper reported the clinical and genetic features of a CBAS2 patient definitely diagnosed by AKR1D1 genetic analysis. An 8-month-old male infant was referred to the hospital with the complaint of jaundiced skin and sclera over 7 months. On physical examination, growth retardation and malnutrition were discovered besides mild jaundice of the skin and sclera. The liver was palpable 8 cm below the right subcostal margin with medium texture, and the spleen was not enlarged. On liver function test, elevated levels of bilirubin (predominantly conjugated bilirubin) and transaminases were detected, but serum total bile acids and γ-glutamyl transpeptidase levels were within the normal ranges. Liver histopathologic analysis showed disorganized bile ducts, obvious multinucleated giant cells, significant cholestasis in hepatocytes, together with portal and interstitial fibrosis and lymphocytic infiltration. Via next generation sequencing analysis and Sanger sequencing confirmation, the infant proved to be a compound heterozygote of the AKR1D1 variants c.579+2delT and c.853C>T(p.Q285X), two novel mutations originated from his mother and father, respectively. CBAS2 was thus definitely diagnosed, and chenodeoxycholic acid was given orally. As a result, the abnormal liver function and hepatomegaly were improved gradually. On a follow-up 3 months later, a soft liver was palpable 2.5 cm below the right subcostal margin, and all liver function indices recovered to normal ranges.

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.

Differential Feedback Regulation of Δ4-3-Oxosteroid 5β-Reductase Expression by Bile Acids

Δ4-3-oxosteroid 5β-reductase is member D1 of the aldo-keto reductase family 1 (AKR1D1), which catalyzes 5β-reduction of molecules with a 3-oxo-4-ene structure. Bile acid intermediates and most of the steroid hormones carry the 3-oxo-4-ene structure. Therefore, AKR1D1 plays critical roles in both bile acid synthesis and steroid hormone metabolism. Currently our understanding on transcriptional regulation of AKR1D1 under physiological and pathological conditions is very limited. In this study, we investigated the regulatory effects of primary bile acids, chenodeoxycholic acid (CDCA) and cholic acid (CA), on AKR1D1 expression. The expression levels of AKR1D1 mRNA and protein in vitro and in vivo following bile acid treatments were determined by real-time PCR and Western blotting. We found that CDCA markedly repressed AKR1D1 expression in vitro in human hepatoma HepG2 cells and in vivo in mice. On the contrary, CA significantly upregulated AKR1D1 expression in HepG2 cells and in mice. Further mechanistic investigations revealed that the farnesoid x receptor (FXR) signaling pathway was not involved in regulating AKR1D1 by bile acids. Instead, CDCA and CA regulated AKR1D1 through the mitogen-activated protein kinases/c-Jun N-terminal kinases (MAPK/JNK) signaling pathway. Inhibition of the MAPK/JNK pathway effectively abolished CDCA and CA-mediated regulation of AKR1D1. It was thus determined that AKR1D1 expression was regulated by CDCA and CA through modulating the MAPK/JNK signaling pathway. In conclusion, AKR1D1 expression was differentially regulated by primary bile acids through negative and positive feedback mechanisms. The findings indicated that both bile acid concentrations and compositions play important roles in regulating AKR1D1 expression, and consequently bile acid synthesis and steroid hormone metabolism.

The aldo-keto reductases (AKRs): Overview

The aldo-keto reductase (AKR) protein superfamily contains >190 members that fall into 16 families and are found in all phyla. These enzymes reduce carbonyl substrates such as: sugar aldehydes; keto-steroids, keto-prostaglandins, retinals, quinones, and lipid peroxidation by-products. Exceptions include the reduction of steroid double bonds catalyzed by AKR1D enzymes (5β-reductases); and the oxidation of proximate carcinogen trans-dihydrodiol polycyclic aromatic hydrocarbons; while the β-subunits of potassium gated ion channels (AKR6 family) control Kv channel opening. AKRs are usually 37kDa monomers, have an (α/β)8-barrel motif, display large loops at the back of the barrel which govern substrate specificity, and have a conserved cofactor binding domain. AKRs catalyze an ordered bi bi kinetic mechanism in which NAD(P)H cofactor binds first and leaves last. In enzymes that favor NADPH, the rate of release of NADP(+) is governed by a slow isomerization step which places an upper limit on kcat. AKRs retain a conserved catalytic tetrad consisting of Tyr55, Asp50, Lys84, and His117 (AKR1C9 numbering). There is conservation of the catalytic mechanism with short-chain dehydrogenases/reductases (SDRs) even though they show different protein folds. There are 15 human AKRs of these AKR1B1, AKR1C1-1C3, AKR1D1, and AKR1B10 have been implicated in diabetic complications, steroid hormone dependent malignancies, bile acid deficiency and defects in retinoic acid signaling, respectively. Inhibitor programs exist world-wide to target each of these enzymes to treat the aforementioned disorders. Inherited mutations in AKR1C and AKR1D1 enzymes are implicated in defects in the development of male genitalia and bile acid deficiency, respectively, and occur in evolutionarily conserved amino acids. The human AKRs have a large number of nsSNPs and splice variants, but in many instances functional genomics is lacking. AKRs and their variants are now poised to be interrogated using modern genomic and informatics approaches to determine their association with human health and disease.

Neonatal liver failure owing to gestational alloimmune liver disease without iron overload

Although neonatal hemochromatosis (NH) is a well-known cause of liver failure during the neonatal period and iron deposition in extrahepatic tissues is considered essential in the diagnosis of NH, there is no consensus regarding the pathology or diagnostic criteria of NH. Recent studies of immunohistochemical assays have shown that the C5b-9 complex (the terminal membrane attack complement complex) is strongly expressed in the liver of NH cases, suggesting that a gestational alloimmune mechanism is the cause of liver injury. The patient was a low birthweight primiparous male born at 37 weeks of gestation by vaginal delivery. Blood tests 3 h after birth showed signs of liver failure, including high transferrin saturation, resembling the clinical characteristics of NH. However, magnetic resonance imaging and a lip biopsy showed no obvious iron deposition outside the liver. The patient was refractory to exchange transfusion and immunoglobulin therapy but was successfully treated by liver transplantation. Histologically, the explanted liver showed established cirrhosis, with large amounts of human C5b-9 in the residual hepatocytes, suggesting the alloimmune mechanism of liver injury was the cause of his liver failure. Liver failure caused by a gestational alloimmune mechanism should be considered in patients with antenatal liver failure, even without obvious extrahepatic siderosis.

Distinguishing primary from secondary Δ(4) -3-oxosteroid 5β-reductase (SRD5B1, AKR1D1) deficiency by urinary steroid analysis

OBJECTIVE

Deficiency of Δ(4) -3-oxosteroid 5β-reductase (5β-reductase), a bile acid synthesis disorder, presents findings of neonatal cholestasis and hyper-3-oxo-Δ(4) bile aciduria. The 5β-reductase enzyme participates in not only bile acid synthesis but also hepatic steroid metabolism. Deficiency of 5β-reductase includes 2 types: primary deficiency, with an SRD5B1 gene mutation; and secondary deficiency, lacking a mutation. Secondary deficiency is caused by fulminant liver failure from various aetiologies including neonatal hemochromatosis (NH). Distinguishing primary from secondary deficiency based on γ-glutamyltransferase (GGT), serum total bile acids (TBA), and urinary bile acid analysis using gas chromatography-mass spectroscopy (GC-MS) is very difficult. SRD5B1 gene analysis is the only reliable method. We examined urinary steroid analysis as a way to distinguish primary from secondary 5β-reductase deficiency.

DESIGN, PATIENTS AND MEASUREMENTS

We examined 12 patients with cholestatic jaundice, normal or slightly elevated GGT, and hyper-3-oxo-Δ(4) bile aciduria using urinary steroid analysis by GC-MS of both cortisol and cortisone compounds, such as 5β-tetrahydrocortisol (5β-THF) and 5β-tetrahydrocortisone (5β-THE). Patients previously were diagnosed with primary 5β-reductase deficiency (n = 3), deficiency secondary to NH (n = 3) and deficiency secondary to other liver disorders (n = 6).

RESULTS

Urinary steroid analysis in 3 primary deficiency and 3 NH patients showed low 5β-THE and elevated 5α/5β-THE ratios, making distinction difficult without also considering the clinical course and abdominal magnetic resonance imaging (MRI) findings, such as a very low signal intensity in liver and/or pancreas, especially in T2 -weighted images. In the six patients with other secondary deficiencies, urinary 5β-THF and 5α/5β-THF differed from those in primary deficiency (P < 0·05).

CONCLUSIONS

Urinary steroid analysis can distinguish primary and NH-related deficiencies from other secondary deficiencies.

Neonatal hemochromatosis: diagnostic work-up based on a series of 56 cases of fetal death and neonatal liver failure

OBJECTIVE

To define an algorithm to improve diagnosis of neonatal hemochromatosis (NH) related to gestational alloimmune liver disease (GALD), which is diagnosed by immunohistochemistry demonstrating activated complement at hepatocytes (IDACH).

STUDY DESIGN

We assessed 56 instances of fetal death or neonatal liver failure (NLF; 2006-2009), 29 (7 stillborns, 22 NLF) with NH, and 27 (5 stillborns, 22 NLF) without NH (non-NH). Immunohistochemistry was retrospectively performed in 21 cases. Cases were grouped as follows: (1) GALD as demonstrated by IDACH (n = 17); (2) indeterminate for GALD (n = 28); or (3) alternate diagnosis found (n = 11). We compared cases of immunohistochemically proven GALD with those with an alternate diagnosis.

RESULTS

Of the 12 stillborns, 7 had NH because of GALD (NH-GALD), one was undeterminate, and 4 had alternate diagnoses (GALD excluded). Of the 22 newborns with NH, 6 had NH-GALD, one had mitochondrial respiratory chain disorder (MRCD), and 15 were indeterminate for GALD. Of 22 non-NH newborns, extrahepatic siderosis (EHS) was not assessed in 13 (3 GALD, 1 alternate diagnosis [MRCD] and 9 indeterminate GALD) and excluded in 9 (5 alternate diagnoses and 4 indeterminate GALD). The only clinical features found to be associated with GALD were intrafamilial recurrence, prematurity, and EHS.

CONCLUSIONS

In unexplained fetal death or NLF, the diagnosis of subsets of NH requires tissue analysis (autopsy) to assess EHS. In patients with NH, if MRCD is ruled out, NH-GALD is likely. The rate of IDACH in the diagnosis of GALD in cases without NH requires further study.

Neonatal hemochromatosis

Neonatal hemochromatosis is a clinical condition in which severe liver disease in the newborn is accompanied by extrahepatic siderosis. Gestational alloimmune liver disease (GALD) has been established as the cause of fetal liver injury resulting in nearly all cases of NH. In GALD, a women is exposed to a fetal antigen that she does not recognize as "self" and subsequently begins to produce IgG antibodies that are directed against fetal hepatocytes. These antibodies bind to fetal liver antigen and activate the terminal complement cascade resulting in hepatocyte injury and death. GALD can cause congenital cirrhosis or acute liver failure with and without iron overload and siderosis. Practitioners should consider GALD in cases of fetal demise, stillbirth, and neonatal acute liver failure. Identification of infants with GALD is important as treatment is available and effective for subsequent pregnancies.

Bile acid metabolism and signaling

Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans.

An efficient synthesis of 7α,12α-dihydroxy-4-cholesten-3-one and its biological precursor 7α-hydroxy-4-cholesten-3-one: Key intermediates in bile acid biosynthesis

This paper describes a method for the chemical synthesis of 7α,12α-dihydroxy-4-cholesten-3-one (1a) and its biological precursor, 7α-hydroxy-4-cholesten-3-one (1b), both of which are key intermediates in the major pathway of bile acid biosynthesis from cholesterol. The principal reactions involved were (1) building of the cholesterol (iso-octane) side chain by 3-carbon elongation of the cholane (iso-pentane) one, (2) oxidation sequence to transform the 3α-hydroxy group of the steroidal A/B-ring to the desired 4-en-3-one system, and (3) appropriate protection strategy for hydroxy groups in the positions at C-7 and C-12 in the steroid nucleus. The absolute structure of 1a and 1b were confirmed by NMR and X-ray crystallography. The targeted compounds 1a and 1b, prepared in 11 steps from 2a and 2b respectively, should be useful for biochemical studies of bile acid biosynthesis or clinical studies of bile acid metabolism, as plasma levels of 1b (also termed C4) have been shown to correlate highly with the rate of bile acid biosynthesis in man.

A combination of mutations in AKR1D1 and SKIV2L in a family with severe infantile liver disease

Infantile cholestatic diseases can be caused by mutations in a number of genes involved in different hepatocyte molecular pathways. Whilst some of the essential pathways have a well understood function, such as bile biosynthesis and transport, the role of the others is not known. Here we report the findings of a clinical, biochemical and molecular study of a family with three patients affected with a severe infantile cholestatic disease. A novel homozygous frameshift germline mutation (c.587delG) in the AKR1D1 gene; which encodes the enzyme Δ ⁴-3-oxosteroid 5β–reductase that is required for synthesis of primary bile acids and is crucial for establishment of normal bile flow, was found in all 3 patients. Although the initial bile acid analysis was inconclusive, subsequent testing confirmed the diagnosis of a bile acid biogenesis disorder. An additional novel homozygous frameshift mutation (c.3391delC) was detected in SKIV2L in one of the patients. SKIV2L encodes a homologue of a yeast ski2 protein proposed to be involved in RNA processing and mutations in SKIV2L were recently described in patients with Tricohepatoenteric syndrome (THES). A combination of autozygosity mapping and whole-exome-sequencing allowed the identification of causal mutations in this family with a complex liver phenotype. Although the initial 2 affected cousins died in the first year of life, accurate diagnosis and management of the youngest patient led to successful treatment of the liver disease and disease-free survival.

French retrospective multicentric study of neonatal hemochromatosis: importance of autopsy and autoimmune maternal manifestations

Neonatal hemochromatosis is a rare disease that causes fetal loss and neonatal death in the 1st weeks of life and is one of the most common causes of liver failure in the neonate. The diagnosis is mostly made retrospectively, based on histopathologic features of severe liver fibrosis associated with hepatic and extrahepatic siderosis. Several etiologies may underlie this phenotype, including a recently hypothesized gestational alloimmune disease. Fifty-one cases of liver failure with intrahepatic siderosis in fetuses and neonates were analyzed retrospectively. Maternal and infant data were collected from hospitalization and autopsy reports. All available slides were reviewed independently by 3 pathologists. Immunologic studies were performed on maternal sera collected immediately after delivery. The diagnosis of neonatal haemochromatosis was retained in 33 cases, including 1 case with Down syndrome and 1 case with myofibromas. Liver siderosis was inversely proportional to fibrosis progression. In fetuses, iron storage was more frequent in the thyroid than in the pancreas. Perls staining in labial salivary glands was positive in 1 of 5 cases. Abnormal low signal intensity by magnetic resonance imaging was detected in the pancreas in 2 of 7 cases. Renal tubular dysgenesis was observed in 7 of 23 autopsy cases. Chronic villitis was seen in 7 of 15 placentas. Half of the mothers presented with an autoimmune background and/or autoantibodies in their sera. Our work highlights the importance of autopsy in cases of neonatal hemochromatosis and marshals additional data in support of the hypothesis that neonatal hemochromatosis could reflect maternal immune system dysregulation.

Deoxyguanosine kinase deficiency presenting as neonatal hemochromatosis

Mutations in DGUOK result in mitochondrial DNA (mtDNA) depletion and may present as neonatal liver failure. Neonatal hemochromatosis (NH(1)) is a liver disorder of uncertain and varied etiology characterized by hepatic and non-reticuloendothelial siderosis. To date, deoxyguanosine kinase (dGK(2)) deficiency has not been formally recognized in cases of NH. We report an African American female neonate with clinical and autopsy findings consistent with NH, and mtDNA depletion due to a homozygous mutation in DGUOK. This report highlights hepatocerebral mtDNA depletion in the differential of neonatal tyrosinemia, advocates considering dGK deficiency in cases of NH, and posits mitochondrial oxidative processes in the pathogenesis of NH.

SRD5B1 gene analysis needed for the accurate diagnosis of primary 3-oxo-Delta4-steroid 5beta-reductase deficiency

BACKGROUND AND AIM

We encounter hyper-3-oxo-Delta(4) bile aciduria in patients with severe cholestatic liver disease or fulminant liver failure during the neonatal period. However, simply by bile acid analysis, it is difficult to distinguish hyper-3-oxo-Delta(4) bile aciduria from primary 3-oxo-Delta(4)-steroid 5beta-reductase deficiency.

METHODS

To determine whether 3-oxo-Delta(4)-steroid 5beta-reductase (SRD5B1) gene analysis is required for the accurate diagnosis of 3-oxo-Delta(4)-steroid 5beta-reductase deficiency, we evaluated the laboratory data, bile acid analysis and SRD5B1 gene analysis from six patients with hyper-3-oxo-Delta(4) bile aciduria.

RESULTS

Based upon the results, four patients who had developed neonatal liver failure were diagnosed as having neonatal hemochromatosis. Two patients with chronic cholestasis were diagnosed as having primary 3-oxo-Delta(4)-steroid 5beta-reductase deficiency by SRD5B1 gene analysis. The SRD5B1 gene in these two patients had a heterozygous mutation, G737A (Gly 223 Glu) in one patient and C217T (Arg 50 stop) in the other.

CONCLUSIONS

Based upon our limited data, we conclude that SDR5B1 gene analysis is required for the accurate diagnosis of 3-oxo-Delta(4)-steroid 5beta-reductase deficiency. Moreover, we think that it is important to elucidate whether there is a heterozygous or a compound heterozygous mutation of the SRD5B1 gene in our two patients.

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.

Review article: The function and regulation of proteins involved in bile salt biosynthesis and transport

BACKGROUND

Bile salts are produced and secreted by the liver and are required for intestinal absorption of fatty food components and excretion of endobiotics and xenobiotics. They are reabsorbed in the terminal ileum and transported back to the liver via the portal tract. Dedicated bile salt transporters in hepatocytes and enterocytes are responsible for the unidirectional transport of bile salts in the enterohepatic cycle.

AIM

To give an overview of the function and regulations of proteins involved in bile salt synthesis and transport.

METHODS

Data presented are obtained from PubMed-accessible literature combined with our own recent research.

RESULT

Hepatocytes and enterocytes contain unique bile salt importers (sodium-taurocholate cotransporting polypeptide and apical sodium-dependent bile acid transporter, respectively) and exporters (bile salt export pump and organic solute transporter alpha-beta, respectively). Enzymes involved in bile salt biosynthesis reside in different subcellular locations, including the endoplasmic reticulum, mitochondria, cytosol and peroxisomes. Defective expression or function of the transporters or enzymes may lead to cholastasis. The bile salt-activated transcription factor Farnesoid X receptor controls expression of genes involved in bile salt biosynthesis and transport.

CONCLUSIONS

Detailed knowledge is available about the enzymes and transporters involved in bile salt homeostasis and how their defective function is associated with cholestasis. In contrast, the process of intracellular bile salt transport is largely unexplored.

New management options for end-stage chronic liver disease and acute liver failure: potential for pediatric patients

The management of children with end-stage chronic liver disease and acute liver failure mandates a multidisciplinary approach and intense monitoring. In recent years, considerable progress has been made in developing specific and supportive medical measures, but studies and publications have mainly concerned adult patients. Therapeutic approaches to complications of end-stage chronic liver disease and acute liver failure (e.g. refractory ascites, hepatorenal syndrome, encephalopathy, and cerebral edema) that may be applied to children are reviewed in this article.Mild-to-moderate ascites should be managed by modest salt restriction and oral diuretic therapy in the first instance. Large volume paracentesis associated with colloid volume expansion and diuretic therapy may be effective for acute relief. Treatment of hepatorenal syndrome type 1 with vasopressin analogs (terlipressin) is recommended prior to liver transplantation in order to improve renal function. Prevention and treatment of chronic hepatic encephalopathy are directed primarily at controlling the events that may precipitate hepatic encephalopathy and at reducing ammonia generation and increasing its detoxification or removal. In addition to reduction of gut ammonia production using non-absorbable disaccharides such as lactulose and/or antibacterials such as neomycin, sodium benzoate may be used on a long-term basis to prevent, stabilize, or improve hepatic encephalopathy. The management of hepatic encephalopathy in acute liver failure is considerably more unsatisfactory; treatment is aimed at preventing brain edema and intracranial hypertension. Extracorporeal liver support devices are now used commonly in critically ill children with acute renal failure, advanced hepatic encephalopathy, cerebral edema, intracranial hypertension, and severe coagulopathy. Continuous renal replacement therapy could potentially help support patients until liver transplantation is performed or liver regeneration occurs. The Molecular Adsorbent Recirculating System (MARS or albumin dialysis) is the liver support system most frequently used worldwide in adults and appears to offer distinct advantages over hepatocyte-based systems. There are no specific medical therapies or devices that can correct all of the functions of the liver. Apart from a few metabolic diseases presenting with severe liver dysfunction for which specific medical therapies may preclude the need for liver transplantation, liver transplantation still remains the only definitive therapy in most instances of end-stage chronic liver disease and acute liver failure. Future research should focus on gaining a better understanding of the mechanisms responsible for liver cell death and liver regeneration, as well as developments in hepatocyte transplantation and liver-directed gene therapy.

Neonatal hemochromatosis--medical treatment vs. transplantation: the king's experience

The aim of our study was to compare the outcome of medical treatment vs. liver transplantation in infants with neonatal hemochromatosis (NH) referred to King's College Hospital from 1990-2002. We conducted a retrospective review of 19 children from 14 families. Fifteen children presented at birth and 4 during the first week of life. One child was diagnosed by cordocentesis at 30 weeks of gestation. NH recurred in 7 of 9 families with further children. In one family, 2 children from different fathers were affected. All patients had elevated ferritin levels, hypoalbuminemia, and coagulopathy. Liver histology showed parenchymal collapse, diffuse fibrosis, and moderate to severe hepatocyte hemosiderin deposition. Extrahepatic siderosis was demonstrated by magnetic resonance in 2 patients, lip biopsy in 3, and autopsy in 10. Ten patients received a chelation-antioxidant cocktail: 1 survived, 4 died, and 5 required liver transplantation, of whom 2 died. One of the 9 infants who did not receive the cocktail survived with medical support, 3 died, and 5 required transplantation, of whom 3 died. Seven children are alive, 5 after transplantation, at a median follow-up of 5.6 years, with excellent quality of life and no recurrence of the disease. In conclusion, chelation-antioxidant treatment does not appear to modify the prognosis of NH, at least in severe cases. Liver transplantation, with 50% long-term survival, remains the treatment of choice and should be promptly offered to those infants who do not improve with supportive medical treatment.

High-dose immunoglobulin during pregnancy for recurrent neonatal haemochromatosis

BACKGROUND

Neonatal haemochromatosis is a rare disease of gestation that results in severe fetal liver injury. We hypothesised an alloimmune aetiology for the disorder on the basis of its high recurrence rate in sibships. In this study, we assessed the effectiveness in preventing or changing the severity of recurrent neonatal haemochromatosis of administering during pregnancy high-dose intravenous immunoglobulin (IVIG) derived from pooled serum of multiple donors.

METHODS

Women whose most recent pregnancy ended in documented neonatal haemochromatosis were treated with IVIG, 1 g/kg bodyweight, weekly from the 18th week until the end of gestation in their subsequent pregnancy. The outcomes of treated pregnancies were compared with those of randomly selected previous affected pregnancies for each woman, which were used as historical controls.

FINDINGS

15 women were treated through 16 pregnancies. All pregnancies progressed uneventfully and resulted in live babies with normal physical examinations and birthweights that were appropriate for gestational age. 12 babies had evidence of liver involvement with neonatal haemochromatosis: 11 had higher than normal concentrations of serum alpha-fetoprotein and ferritin or serum alpha-fetoprotein alone, including four with coagulopathy (international normalised ratio >1.5), and one had coagulopathy alone. All babies survived with medical or no treatment and were healthy at follow-up within the past 6 months. In analysis on a per-mother basis comparing outcomes of treated gestations with those of randomly selected previous affected gestations, gestational IVIG therapy was associated with better infant survival (15 good outcomes vs two in previous pregnancies; p=0.0009).

INTERPRETATION

Treatment with high-dose IVIG during gestation appears to have modified recurrent neonatal haemochromatosis so that it was not lethal to the fetus or neonate. These results further support an alloimmune mechanism for recurrent neonatal haemochromatosis.

Neonatal hemochromatosis

Neonatal hemochromatosis is a rare gestational condition in which iron accumulates in the fetal tissues in a distribution like that seen in hereditary hemochromatosis. Extensive liver damage is the dominant clinical feature, with late fetal loss or early neonatal death. NH recurs within sibships at a rate higher than that predicted for simple Mendelian autosomal-recessive inheritance, possibly suggesting the role of a maternal factor. Immunomodulation during pregnancy at risk appears to lessen the severity of disease.

Progress in treatment and outcome for children with neonatal haemochromatosis

AIM

To evaluate the role of antioxidant treatment and liver transplantation in the management of neonatal haemochromatosis.

METHODS

A retrospective review was performed of eight infants with acute liver failure and raised ferritin levels between 1990 and 1998. From 1994, treatment with an antioxidant cocktail (vitamin E, N-acetylcysteine, selenium, prostaglandin E1, and desferrioxamine) was begun once the diagnosis was suspected. Pathological and other findings were reviewed, and outcome before and after antioxidant treatment was evaluated.

RESULTS

Median age at presentation was 4 days with median ferritin levels of 4180 micro g/l (range 1650-40 000 micro g/l; normal range 110-503 micro g/l). Three infants presented before 1994. One infant died before liver transplantation from acute liver failure and one from neurological damage after transplantation. The third patient underwent successful transplantation at day 13 and remains well on follow up 8 years later. From 1994, five patients received antioxidant treatment, of whom two responded: both responders started antioxidants earlier (by day 5) than non-responders and had lower peak ferritin levels (< 4200 micro g/l) and a milder phenotype. Treatment was continued until ferritin levels were < 500 micro g/l. Both children remain well with mean follow up of 42 months, with no recurrence of iron overload. One child showed a partial response to treatment and survived long enough for a liver transplant, but died from graft failure after the transplant. Two children did not respond to antioxidant treatment; both had multiorgan failure and were not listed for transplantation. Only three of the eight patients survived (37.5%) over this time period.

CONCLUSION

Neonatal haemochromatosis can be a fatal disease with > 60% mortality. Early treatment with antioxidant cocktail is beneficial and may be curative in those who present with milder phenotype. Liver transplantation should always be considered at an early stage in non-responders and in children with more severe acute liver failure.

Bile acid regulation of gene expression: roles of nuclear hormone receptors

Bile acids derived from cholesterol and oxysterols derived from cholesterol and bile acid synthesis pathways are signaling molecules that regulate cholesterol homeostasis in mammals. Many nuclear receptors play pivotal roles in the regulation of bile acid and cholesterol metabolism. Bile acids activate the farnesoid X receptor (FXR) to inhibit transcription of the gene for cholesterol 7alpha-hydroxylase, and stimulate excretion and transport of bile acids. Therefore, FXR is a bile acid sensor that protects liver from accumulation of toxic bile acids and xenobiotics. Oxysterols activate the liver orphan receptors (LXR) to induce cholesterol 7alpha-hydroxylase and ATP-binding cassette family of transporters and thus promote reverse cholesterol transport from the peripheral tissues to the liver for degradation to bile acids. LXR also induces the sterol response element binding protein-1c that regulates lipogenesis. Therefore, FXR and LXR play critical roles in coordinate control of bile acid, cholesterol, and triglyceride metabolism to maintain lipid homeostasis. Nuclear receptors and bile acid/oxysterol-regulated genes are potential targets for developing drug therapies for lowering serum cholesterol and triglycerides and treating cardiovascular and liver diseases.

Idiopathic neonatal giant cell hepatitis presenting with acute hepatic failure on postnatal day one

We report a term male infant presenting on postnatal day 1 with fulminant hepatic failure. Described congenital infection, metabolic disorders, and cardiovascular etiologies of acute neonatal liver failure were assessed and eliminated. A liver biopsy on postnatal day 10 showed neonatal giant cell hepatitis (NGCH) with an unusual degree of fibrosis for this early postnatal age. NGCH is a clinical diagnosis of cholestatic disorders of unknown etiology in the newborn, and, to our knowledge, has not been previously associated with immediate neonatal hepatic failure. The giant cell transformation is a common response to a variety of insults and only rarely occurs beyond the neonatal period. Most cases present with cholestatic jaundice and varying degrees of coagulopathy, and, many, as in this case, show progressive resolution.

Hepatic failure with neonatal tissue siderosis of hemochromatotic type in an infant presenting with meconium ileus. Case report and differential diagnosis of the perinatal iron storage disorders

We report on a female preterm infant with hepatic failure and neonatal tissue siderosis of hemochromatotic type diagnosed by using both histochemistry and atomic absorption spectroscopy. The infant presented with meconium ileus, signs of rapidly progressive hepatic failure, and hyperferritinemia (7132 ng/ml). Despite surgery and intensive care the infant died 32 days after birth. Postmortem examination showed a wrinkled liver with extensive collapse of the hepatic architecture and regenerating nodules as well as hepatic and extrahepatic iron accumulation of hemochromatotic type, sparing the reticuloendothelial system. Atomic absorption spectroscopy confirmed an increase in the iron content of various organs: liver, heart, pancreas, oral salivary gland, kidney, and adrenal gland. The increase in the iron content of various organs was determined by comparing the analysis of the propositus with those of 5 gestationally age-related preterm infants who had died in the intensive care unit: 2 died of meconium aspiration syndrome, the other 3 of hyaline membrane disease, bronchopulmonary dysplasia, and immaturity, respectively. We also compared the analysis of 15 fetuses having a a condition predisposing to iron accumulation (trisomy 21, trisomy 18, cytomegalovirus, amnion infection syndrome, Rhesus- and ABO-incompatibility, congenital hemolysis, anti-phospholipid syndrome, congenital heart disease). Delta F508, the most frequent mutation seen in cystic fibrosis patients, was excluded by gene sequencing. Different noxae causing iron accumulation in the neonatal period have led to the statement that neonatal hemochromatosis may collect different etiologies, such as metabolic disorders, infections, chromosomal aberrations, and immunological disorders. In this study, we report the singular evidence of neonatal iron accumulation of hemochromatotic type in an infant presenting with meconium ileus and propose a classification of the neonatal disorders associated with iron accumulation.

Mechanisms of liver injury relevant to pediatric hepatology

Hepatocyte injury and necrosis from many causes may result in pediatric liver disease. Influenced by other cell types in the liver, by its unique vascular arrangements, by lobular zonation, and by contributory effects of sepsis, reactive oxygen species and disordered hepatic architecture, the hepatocyte is prone to injury from exogenous toxins, from inborn errors of metabolism, from hepatotrophic viruses, and from immune mechanisms. Experimental studies on cultured hepatocytes or animal models must be interpreted with caution. Having discussed general concepts, this review describes immune mechanisms of liver injury, as seen in autoimmune hepatitis, hepatitis B and C infection, the anticonvulsant hypersensitivity syndrome, and autoimmune polyendocrinopathy. Of the monogenic disorders causing significant liver injury in childhood, alpha-1 antitrypsin deficiency and Niemann-Pick C disease demonstrate the effect of endoplasmic or endosomal retention of macromolecules. Tyrosinemia illustrates how understanding the biochemical defect leads to understanding cell injury, extrahepatic porphyric effects, oncogenesis, pharmacological intervention, and possible stem cell therapy. Pathogenesis of cirrhosis in galactosemia remains incompletely understood. In hereditary fructose intolerance, phosphate sequestration causes ATP depletion. Recent information about mitochondrial disease, NASH, disorders of glycosylation, Wilson's disease, and the progressive familial intrahepatic cholestases is discussed.

Classification and genetic features of neonatal haemochromatosis: a study of 27 affected pedigrees and molecular analysis of genes implicated in iron metabolism

Neonatal haemochromatosis (NH) is a severe and newly recognised syndrome of uncertain aetiology, characterised by congenital cirrhosis or fulminant hepatitis and widespread tissue iron deposition. NH occurs in the context of maternal disease including viral infection, as a complication of metabolic disease in the fetus, and sporadically or recurrently, without overt cause, in sibs. Although an underlying genetic basis for NH has been suspected, no test is available for predictive analysis in at risk pregnancies. As a first step towards an understanding of the putative genetic basis for neonatal haemochromatosis, we have conducted a systematic study of the mode of transmission of this disorder in a total of 40 infants born to 27 families. We have moreover carried out a molecular analysis of candidate genes (beta(2)-microglobulin, HFE, and haem oxygenases 1 and 2) implicated in iron metabolism. No pathogenic mutations in these genes were identified that segregate consistently with the disease phenotype in multiplex pedigrees. However, excluding four pedigrees with clear evidence of maternal infection associated with NH, a pedigree showing transmission of maternal antinuclear factor and ribonucleoprotein antibodies to the affected infants, and two families with possible matrilineal inheritance of disease in maternal half sibs, a large subgroup of the affected pedigrees point to the inheritance of an autosomal recessive trait. This included 14 pedigrees with affected and unaffected infants and a single pedigree where all four affected infants were the sole offspring of consanguineous but otherwise healthy parents. We thus report three distinct patterns of disease transmission in neonatal haemochromatosis. In the differentiation of a large subgroup showing transmission of disease in a manner suggesting autosomal recessive inheritance, we also provide the basis for further genome wide studies to define chromosomal determinants of iron storage disease in the newborn.

Liver disease caused by disorders of bile acid synthesis

Bile acid synthetic defects are uncommon disorders that cause progressive cholestatic liver disease that is often lethal in infancy or early childhood. Five specific primary defects have been described. Diagnosis is based on mass spectrometry of urine and serum. Pathogenesis of liver injury is related to persistent reduction in levels of normal bile acids and accumulation of abnormal, potentially hepatotoxic, intermediaries. Sites of injury are the liver cell, the bile canaliculus, and the smallest bile ductules. The interlobular bile ducts are normal. The liver lesion is progressive chronic hepatitis with an especially high incidence of GCT in patients who present in infancy. Bile acid replacement therapy is usually effective in arresting the liver injury. Regression of liver damage has been documented during treatment of patients who were diagnosed early in life. Because bile acid synthetic disorders are the only cholestatic diseases of infancy in which GCT of hepatocytes is consistently present, the author suggest that the injury responsible for GCT may be specific for toxic bile acids. Accordingly, immaturity of the bile acid synthetic pathway may render many otherwise normal infants vulnerable to transient "neonatal hepatitis" with GCT in a broad range of cholestatic disorders.

Inborn errors of bile acid biosynthesis and transport. Novel forms of metabolic liver disease

Defective bile acid biosynthesis, metabolism, and transport can now be delineated in a wide variety of disease states. This ability to recognize specific aberrations, such as the documented inborn errors in bile acid biosynthesis manifesting as neonatal cholestasis, offers new opportunities for therapeutic intervention. Future studies should determine the incidence of bile acid biosynthetic and transport defects in patients with enigmatic and unexplained liver diseases.

Tyrosinemia type I-like disease: a possible manifestation of 3-oxo-delta 4-steroid 5 beta-reductase deficiency

BACKGROUND

It has been suggested that quantitative analysis of urinary bile acids may help to distinguish primary 3-oxo-delta 4-steroid 5 beta-reductase deficiency from the excretion of 3-oxo-delta 4 bile acids that occurs as a result of liver damage.

METHODS

Urinary bile acids were quantitatively analyzed by gas chromatography-mass spectrometry in four Japanese patients with severe neonatal cholestasis associated with hypertyrosinemia without urinary succinylacetone (i.e. tyrosinemia type I-like disease). These four patients represented sporadic cases.

RESULTS

Large amounts of 3-oxo-delta 4 bile acids were detected, which comprised greater than 80% of the total urinary bile acids. Small amounts of allo-bile acids and primary bile acids were also detected, comprising less than 1% and 15% of the total urinary bile acids, respectively.

CONCLUSIONS

It was suspected that these four patients had a primary 3-oxo-delta 4-steroid 5 beta-reductase deficiency. However, it is possible that some patients in this study may have had a secondary 3-oxo-delta 4-steroid 5 beta-reductase deficiency, caused by idiopathic neonatal cholestatic liver failure.

Other hereditary diseases and the liver

In this chapter, an abbreviated account is presented on the subject of hereditary diseases and the liver. However, it is incomplete because Alagille syndrome, storage disorders, alpha-1-antitrypsin deficiency and Wilson disease are not included as they appear in other chapters of this volume. Biliary atresia is omitted because all available evidence does not support any significant genetic association. Molecular biological techniques have enabled linkage of several liver cholestatic disorders to chromosomal loci, and further characterization of the canalicular bile salt transporter (cBST) will advance our understanding of pathogenetic mechanisms involved in benign and progressive cholestatic syndromes. Disorders that have been treated as separate entities may have common 'roots', exemplified by the concept of the ductal plate malformation in fibropolycystic disease. Whereas the majority of disorders referred to in this chapter present early in life, there are several that are associated with liver failure in the neonatal period, which makes early recognition particularly important. Liver transplantation offers a cure for many hereditary disorders affecting the liver but it is not applicable to all.

Diagnosis of the first Japanese patient with 3-oxo-delta4-steroid 5beta-reductase deficiency by use of immunoblot analysis

A 3-oxo-delta4-steroid 5beta-reductase (5beta-reductase) deficiency is difficult to diagnose because severe liver damage can result in a similar pattern of metabolite excretion. We investigated the usefulness of immunoblot analysis for diagnosis of 5beta-reductase deficiency and quantitatively analysed urinary bile acids by gas chromatography-mass spectrometry in a 5-month-old Japanese boy with severe neonatal cholestasis associated with hypertyrosinaemia. A liver sample was examined by immunoblot analysis using monoclonal antibodies against 5beta-reductase. Urinary 3-oxo-delta4 bile acids accounted for 88.3% of total bile acids, 5alpha-bile acids for 0.9%, and primary bile acids for 9.1%. Immunoblot analysis of the liver tissue showed an indistinct band of 5beta-reductase.

CONCLUSIONS

These findings suggest that this patient had a secondary 5beta-reductase deficiency due to severe liver damage, even though 3-oxo-delta4 bile acids constituted more than 70% of total urinary bile acids. However, the patient may possibly have had an inherited 5beta-reductase deficiency.

Neonatal intrahepatic cholestasis with hepatic siderosis and steatosis

Neonatal intrahepatic cholestasis is a heterogeneous disease of undetermined cause. There is an unreported subset of idiopathic neonatal intrahepatic cholestasis with an unusual histological combination of hepatic siderosis and macrovesicular steatosis. The patients were a 34-day-old female and a 39-day-old male with normal birth weights. Their mothers had received oral iron supplement 4-6 weeks before delivery. The patients had obstructive jaundice noticed at the well-baby clinic at 1 month of life. They had high levels of serum galactose and tyrosine, hyperferritinemia. Urinary organic acid and bile acid analyses were negative, and galactose-1-phosphate uridyltransferase activity in red cells was normal. Liver biopsies showed diffuse iron deposits and macrovesicular fat. By substituting formula milk with lactose-free milk, the patients responded, and had normal biochemical tests within 5 months of life. Follow-up biopsies, at the age of 12 months, showed mild residual fibrosis without iron or fat deposits. They are both well at 3 and 6 years of age, respectively, without biochemical liver dysfunction and neurologic impairment. Prenatal iron-overload might contribute to the pathogenesis of the disease, but further studies are needed to confirm the assumption.

Urinary 7alpha-hydroxy-3-oxochol-4-en-24-oic and 3-oxochola-4,6-dien-24-oic acids in infants with cholestasis

BACKGROUND/AIMS

Urinary 3-oxo-delta4 bile acids have been detected in infants who ultimately died of liver disease. We used qualitative and quantitative methods to compare urinary 3-oxo-delta4 bile acids in liver disease, determining their composition and evaluating the prognostic implication in patients of various ages with various liver diseases.

METHODS

Gas chromatography-mass spectrometry was used to measure 3-oxo-delta4 bile acids in the urine of patients and healthy controls.

RESULTS

Patients with a deficiency of 3-oxo-delta4-steroid 5beta-reductase and acute hepatic failure exhibited a significantly higher percentage of 3-oxo-delta4 bile acids in total bile acids in urine than the healthy controls or other patient groups, including those with neonatal cholestasis or biliary atresia (p<0.0001). The urinary 3-oxo-delta4 bile acids in patients with 3-oxo-delta4-steroid 5beta-reductase deficiency who had a poor prognosis were mainly 7alpha-hydroxy-3-oxochol-4-en-24-oic acid and 3-oxochola-4,6-dien-24-oic acid.

CONCLUSIONS

Our results indicate that an increase in the 7alpha-hydroxy-3-oxochol-4-en-24-oic acid and 3-oxochola-4,6-dien-24-oic acid in the urine of patients with hepatobiliary disease indicates a poor prognosis.

Neonatal hemochromatosis: outcomes of pharmacologic and surgical therapies

BACKGROUND

Neonatal hemochromatosis (NH), also known as perinatal hemochromatosis or neonatal iron storage disease, is a disorder in fetuses and newborn infants. A retrospective study was conducted to report management of patients with NH.

METHODS

Retrospective analysis was conducted by chart review and by review of histologic material from patients with NH.

RESULTS

Neonatal hemochromatosis was diagnosed in 14 patients between 1985 and 1995. All were considered for orthotopic liver transplantation (OLTX). From 1993 onward, all patients were treated with an antioxidant-chelation "cocktail," consisting of deferoxamine, vitamin E, N-acetylcysteine, selenium, and prostaglandin-E1. Of 6 patients with NH diagnosed before 1993, 4 underwent OLTX; only 1 is still alive. Of 8 patients with NH diagnosed after 1993 and treated with the cocktail, 7 expired before OLTX. One stabilized on therapy, but having never recovered full synthetic liver function, underwent OLTX and is now alive and well.

CONCLUSION

Neonatal hemochromatosis carries a grim prognosis; however, successful OLTX is curative. The use of an antioxidant-chelation cocktail did not improve outcome in the patients studied. Earlier (perinatal) diagnosis may be required for optimal results. Further study of other interventions, including antenatal diagnosis and earlier institution or modification of cocktail therapy appears warranted.

[Progressive familial intrahepatic cholestasis and hereditary anomalies lf hepatocellular metabolism of bile acids]

Progressive familial intrahepatic cholestasis (PFIC), also known as Byler disease, is an inherited cholestasis of hepatocellular origin which is characterized by cholestasis presenting often in the neonatal period leading to death due to liver failure at ages ranging from infancy to adolescence. The pattern of appearance of affected children within families is consistent with autosomal recessive inheritance. The etiology is poorly understood but several studies have recently provided support for an heterogeneity with at least three subcategories among the spectrum of PFIC. The first subtype is characterized by an early onset, often during the neonatal period, a severe pruritus, normal serum gamma-glutamyltransferase (GGT) activity and cholesterol level, high concentration of serum primary bile acids, absence or very low levels of primary bile acids, absence or very low levels of primary bile acids in bile, and absence of ductular proliferation on standard optical liver histology. Its leads to death due to liver failure within a few years, rarely after adolescence. It is possibly due to an inborn error in primary bile acid secretion and recently, a locus for this subtype has been mapped in the original Byler pedigree to 18q21-q22, the benign recurrent intrahepatic cholestasis region. In the second subtype, affected children exhibit also normal serum GGT activity and cholesterol level and absence of ductular proliferation, but have no pruritus and only traces of primary bile acids in serum. An inborn error in primary bile acid synthesis has been demonstrated in this subtype. The third subtype presents later in life, carries a higher risk of portal hypertension and gastrointestinal bleeding and ends in liver failure at a later age. It is characterized by a mild and unconstant pruritus, high GGT serum activity, moderately raised concentrations of serum primary bile acids, normal concentration of biliary primary bile acids, and ductular proliferation and inflammatory infiltrate with patency of intra and extrahepatic bile ducts. An abnormal expression of the MDR3 gene is involved. A fair proportion of children affected with all subtypes of PFIC may benefit from oral bile acid therapy. In some cases partial external biliary diversion or liver transplantation should be proposed.