Bile Acid Abnormalities and the Diagnosis of Cerebro-Hepato-Renal Syndrome (Zellweger Syndrome)

ABSTRACT. The Zellweger or cerebro-hepato-renal syndrome (CHRS) is a congenital disorder characterized by cerebral dysfunction, craniofacial dysmorphic features, transient cholestasis and renal cysts. Patients fail to thrive, and usually die in their first year of life. In some cases, a definite diagnosis on purely clinical signs might not be possible. Several biochemical abnormalities have been observed in these patients and some of them have been tested as diagnostic markers. The aim of this study is to evaluate bile acid metabolites as biochemical markers of the CHRS. From a study of 20 CHRS patients, we conclude that screening for the presence of coprostanic acids and the C-29 dicarboxylic bile acid in serum or urine is a reliable method for detection of CHRS and confirmation of the diagnosis.     

Bile acids and bile alcohols in two patients with Zellweger (cerebro-hepato-renal) syndrome

The Zellweger cerebro-hepato-renal syndrome (CHRS) is a rare hereditary disease in which there is a generalized deficiency of peroxisomal function. Liver peroxisomes are important for the conversion of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid into cholic acid, and, consequently, 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid and metabolites of this bile acid precursor accumulate in serum and bile of patients with CHRS. Little is known about the urinary excretion of bile acids in this disease. Using gas chromatography-mass spectrometry we have analyzed serum bile acids and urinary excretion of bile acids and bile alcohols in two Swiss male CHRS patients. As expected, serum concentrations and urinary excretions of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid and 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestanoic acid were elevated, which is probably an obligatory finding in CHRS. In addition, the urinary excretion of 1,3,7,12-tetrahydroxy-5 beta-cholanoic acid (a very polar unusual bile acid) was increased (99-1556 nmol/24 h). In contrast, the excretion of the major urinary bile alcohol, 27-nor-5 beta-cholestane-3 alpha, 7 alpha,12 alpha,24,25-pentol was found to be normal. 3 alpha, 7 alpha,12 alpha-Trihydroxy-5 beta-C29-dicarboxylic acid, a metabolite of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid previously believed to be obligatory in CHRS, was found only in one of our patients.     

Evaluation and management of steroid-unresponsive nephrotic syndrome

PURPOSE OF REVIEW: Idiopathic nephrotic syndrome in children is commonly associated with minimal change disease and response to steroid therapy. Steroid-unresponsive nephrotic syndrome is often characterized by persistent proteinuria and progression to chronic kidney disease. Focal segmental glomerulosclerosis is the leading cause of steroid-unresponsive nephrotic syndrome in childhood. There is no uniformed consensus as to the treatment of steroid-unresponsive nephrotic syndrome. Advances in the pathogenesis, genetics and biomarkers or surrogate markers may be useful for the diagnosis and identification of patients with steroid-unresponsive nephrotic syndrome, severity of disease, progression and response to therapy. RECENT FINDINGS: This review is intended to describe some of the recent changes in the epidemiology of steroid-unresponsive nephrotic syndrome, in particular focal segmental glomerulosclerosis, its pathogenesis and alternative therapies. SUMMARY: Recent studies in both children and adults have shown an increase in the incidence of focal segmental sclerosis as a cause of steroid-unresponsive nephrotic syndrome. Advances in the pathogenesis and noninvasive methods of diagnosis may allow for the identification of steroid-responsive patients.     

Serum indoxyl sulfate as an early marker for detecting chronic cyclosporine nephrotoxicity

Background: Cyclosporine A (CsA) is an effective agent for frequently relapsing steroid‐dependent nephrotic syndrome (FR‐SDNS), but its use can also be complicated by renal toxicity. Because no biochemical markers from urine or blood samples have yet been established for detecting CsA‐induced renal injury to date, repeated renal biopsies are therefore required for all patients with long‐term CsA treatment. The purpose of the present study was therefore to detect early change of CsA nephropathy (CsAN) using blood samples. Methods: Several biochemical markers were analyzed in an attempt to examine the renal function in 24 patients with FR‐SDNS who had been treated with CsA. Those included serum cystatin C and indoxyl sulfate, as well as creatinine and β2‐microglobulin. Results: Renal biopsy findings indicated chronic CsAN in 13 of the 24 patients. Among those markers, only serum indoxyl sulfate was significantly elevated in patients with CsAN. Conclusions: It may be possible for measurement of serum indoxyl sulfate level to replace repeated renal biopsies in evaluation of chronic CsAN in pediatric patients with FR‐SDNS.     

Peroxisomal dysfunction in a boy with neurologic symptoms and amaurosis (Leber disease): clinical and biochemical findings similar to those observed in Zellweger syndrome

A boy with psychomotor retardation and Leber congenital amaurosis, sensory hearing loss, and hepatomegaly is reported. Accumulation of bile acid precursors and very long chain fatty acids together with impaired biosynthesis of plasmalogens in cultured fibroblasts (similar to those in the cerebrohepatorenal syndrome of Zellweger) were detected, but the clinical picture was distinctly different. Defective oxidation of phytanic acid was measured in fibroblasts. The virtual lack of peroxisomes in a liver biopsy specimen lends further support to the contention that at least some patients with Leber congenital amaurosis may have one of the recently defined "peroxisomal disorders." The biochemical findings indicate the possibility of prenatal diagnosis.     

Central nervous system candidiasis in preterm infants: limited value of biochemical markers for diagnosis

Two rare cases of isolated central nervous system (CNS) candidiasis in preterm infants have been diagnosed in a tertiary neonatal centre over the past 6 years. Despite the life-threatening nature of the disease, biochemical infection markers were not useful for the early identification of localized fungal infection. Because the infection was likely to have been blood borne, we postulated that the initial fungal load was probably low and that the organisms were rapidly eliminated from the circulation after a few had been deposited in the CNS. Hence, the absence of fungaemia or systemic involvement precluded the activation of cytokines and cellular markers. Clinicians should be aware of the limitation of biochemical infection markers so that diagnosis and treatment of fungal infection will not be delayed.     

Zellweger's syndrome (cerebro-hepato-renal syndrome)--its clinical picture, morphology and biochemical diagnosis

The cerebro-hepato-renal (Zellweger) syndrome is characterised by dysmorphic features, severe muscular hypotonia, hepatic dysfunction and early death in infancy. Recently it has been shown that the disease is an inborn error of metabolism with an unusual variety of metabolic disturbances affecting pipecolic acid, bile acids, plasmalogens and very long chain fatty acids. Ultrastructural and biochemical findings confirming the diagnosis are illustrated. The syndrome is inherited as an autosomal recessive trait, prenatal diagnosis has become possible.     

Chediak-Higashi syndrome

The use of cytochemical, electron microscopic, immunofluorescent, and tissue culture techniques has led to important advances in our understanding of the mechanisms underlying the pathogenesis of the Chediak-Higashi syndrome (CHS). This rare and fatal autosomal recessive disorder is clinically characterized by partial albinism, frequent pyogenic infections, and an accelerated lymphohistiocytic phase. The pathological hallmark of CHS is the presence in all white blood cells of massive lysosomal inclusions, which are formed through a combined process of fusion, cytoplasmic injury, and phagocytosis. The abnormal inclusions exhibit both azurophilic and specific granular markers, and are probably responsible for most of the impaired leukocyte and other cell functions in CHS patients. In addition, a selective profound natural killer (NK) cell function and platelet storage pool deficiencies have been described in these patients. Impaired microtubule assembly and functions, mediated by abnormal intracellular cyclic nucleotide levels, which could be corrected by treatment with ascorbic acid, were suggested to be the pathophysiological basis for CHS abnormalities. However, some recent studies have questioned this cytoskeletal model, which is suggested to be rather a secondary manifestation of CHS.     

Cerebrospinal fluid values for monoamine metabolites, gamma-aminobutyric acid, and other amino compounds in Rett syndrome

We measured concentrations of 3-methoxy-4-hydroxy-phenylglycol, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid--the metabolites of noradrenaline, dopamine, and serotonin used as central neurotransmitters--in the cerebrospinal fluid (CSF) specimens of five girls with Rett syndrome. These patients met the clinical criteria for both inclusion and exclusion of the diagnosis of Rett syndrome. In contrast to previous reports, cerebral monoamine metabolites were present in normal concentrations in CSF. In addition, concentrations of gamma-aminobutyric acid and of a large number of other amino acids and related compounds were normal in the CSF of patients with the syndrome. We doubt that an underlying biochemical cause for this disorder has yet been discovered.     

Sickle cell nephropathy: A review of novel biomarkers and their potential roles in early detection of renal involvement

Whether the underlying mutations are homozygous, heterozygous, or co-inherited with other hemoglobinopathies, sickle cell disease is known to afflict the kidneys, leading to the clinical entity known as sickle cell nephropathy (SCN). Although common, SCN remains diagnostically elusive. Conventional studies performed in the context of renal disorders often fail to detect early stage SCN. This makes the quest for early diagnosis and treatment more challenging, and it increases the burden of chronic kidney disease-related morbidity among patients. Novel diagnostic tools have been employed to overcome this limitation. In this study, we discuss various biomarkers of SCN, including those employed in clinical practice and others recently identified in experimental settings, such as markers of vascular injury, endothelial dysfunction, tubulo-glomerular damage, and oxidative stress. These include kidney injury molecule-1, monocyte chemoattractant protein-1, N-acetyl-B-D-glucosaminidase, ceruloplasmin, orosomucoid, nephrin, and cation channels, among others. Furthermore, we explore the potential of novel biomarkers for refining diagnostic and therapeutic approaches and describe some obstacles that still need to be overcome. We highlight the importance of a collaborative approach to standardize the use of promising new biomarkers. Finally, we outline the limitations of conventional markers of renal damage as extensions of the pathogenic process occurring at the level of the organ and its functional subunits, with a discussion of the expected pattern of clinical and biochemical progression among patients with SCN.     

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??Abstract?? Objective??To evaluate the value of biochemical markers in the diagnosis of biliary atresia ??BA?? and neonatal intrahepatic cholestasis caused by citrin deficiency ??NICCD??. Methods??Totally 77 infants in hospital with infantile hepatitis syndrome ??IHS?? were enrolled from December 1?? 2008 to March 31?? 2009. Totally 27 patients were diagnosed as having BA and 11 with NICCD. Biochemical markers were compared between groups including alanine transaminase ALT?? aspartate transaminase AST ?? alkaline phosphatase ALP?? γ-glutamyl transpeptidase γ-GT?? total bilirubin TB?? direct bilirubin DB?? total bile acid TBA?? total cholesterol TC??to compute ALT/AST??ALP/γ-GT and glucose GLU?? lactic acid LAC?? total protein TP?? albumin ALB in the NICCD group. The data were analyzed by T test and ROC curve with SPSS10.0. Results??γ-GT was significantly elevated in the infants with BA when compared to non-BA group ??P = 0.003???? cut-off point was 332.5U/L. ALP/γ-GT was significantly lower in the patients with BA??and cut-off point was 1.93. The infants with NICCD had significantly different biochemical markers including GLU?? LAC?? TP?? ALB?? ALT/AST and γ-GT. Conclusion??Biochemical markers could be considered as complementary diagnosis of BA and NICCD for differentiating infants with IHS.     

Duodenogastric reflux in children: measurement of phospholipids and trypsin in gastric content

The duodenogastric reflux (DGR) is a suspected cause in some esogastric pathologies in adults: esophagitis, peptic gastric ulcers, stress ulcers, ulcers secondary to drugs, gastric cancer, and gastritis. The toxic substances of the reflux are essentially bile acids, lysolecithin, and trypsin. A number of diagnostic methods have been proposed in the adult. This study suggests a diagnosis technique for DGR in the child. Fasting gastric juice was collected by gastric intubation during 1 h and three substances were measured: phospholipids as markers of biliary reflux, trypsin as a marker of pancreatic reflux, and sialic acid as a marker of the degradation of gastric mucus. The sialic acid enabled us to evaluate some of the toxicity of DGR on the stomach. The study of 49 child subjects permitted us to show the existence, in the normal child, of biliopancreatic markers in the stomach under fasting conditions through a physiological DGR; to define the norms in the child, varying according to three age groups: 0-2 months, 2-12 months, and 1-4 years (the maximum values for an age above 4 years seemed to correspond to those in the adult); and to suggest the existence of a pathological DGR in children with antral gastritis or ulcers.     

The ontogeny of biochemical markers of cardiac dysfunction

PURPOSE OF REVIEW: Biochemical markers are available to detect cardiac involvement in many pediatric disease states and should be considered. RECENT FINDINGS: Analyses of three markers are readily available in clinical laboratories for improved diagnosis. SUMMARY: Increased workload of the heart has been associated with the release of biochemical markers (natriuretic peptides and cardiac enzymes) that indicate that a new genetic program has been activated and maladaptation is occurring in the atria, ventricles, or both. This review summarizes those that have been identified in fetal and pediatric practice. The expression of such markers is traced from early embryonic development to fetal life, to the neonate, to childhood, and then to adult life.     

Quantitative acylcarnitine profiling in peripheral blood mononuclear cells using in vitro loading with palmitic and 2-oxoadipic acids: biochemical confirmation of fatty acid oxidation and organic acid disorders

Organic acid (OAD) and fatty acid oxidation disorders (FAOD) are inborn errors of metabolism often presenting with life-threatening metabolic decompensation followed by (irreversible) organ failure, and even death during catabolic state. Most of these diseases are considered as treatable, and metabolic decompensations can be avoided by early diagnosis and start of therapy. Confirmation of suspected diagnosis currently relies on enzymatic and mutation analyses and in vitro loading of palmitic acid in human skin fibroblast cultures. Furthermore, in some cases potentially life-threatening in vivo loading or fasting tests are still performed. In this study, we established a standardized in vitro loading test in peripheral blood mononuclear cells (PBMC) that allows reliable biochemical confirmation of a suspected diagnosis within 1 week. Patients with confirmed diagnosis of short-, medium-, very-long-chain, and long-chain 3-hydroxyacyl-CoA dehydrogenase deficiencies, methylmalonic, propionic, isovaleric acidurias, and glutaric aciduria type I were included in the study. PBMC, isolated from heparinized venous blood samples of these individuals were incubated for 5 days with palmitic acid or 2-oxoadipic acid (glutaric aciduria type I), respectively, and quantitative acylcarnitine profiling was subsequently performed in supernatants using electrospray ionization tandem mass spectrometry. All patients were clearly identified, including those with mild biochemical phenotypes who, in particular, are at risk to be missed under balanced metabolic conditions. In glutaric aciduria type I, the same results were also obtained using lymphoblasts. In conclusion, our assay allows biochemical confirmation of a number of FAOD and OAD and could easily be implemented into the confirmatory diagnostic work-up.     

Incidence of Smith-Lemli-Opitz syndrome in Canada: results of three-year population surveillance

OBJECTIVES: To determine the incidence and point prevalence of Smith-Lemli-Opitz syndrome (SLOS) in Canada; to determine the percentage of mild cases of SLOS; and to determine the age of diagnosis of mildly affected patients. SLOS is a treatable genetic condition that may be difficult to diagnose in its mildest form because of nonspecific clinical markers (two- to three-toe webbing, short upturned nose, and micrognathia). STUDY DESIGN: More than 2000 Canadian pediatricians and pediatric specialists were surveyed monthly for 36 months through a standing national surveillance program. A clinical identification form was designed to identify patients with SLOS or its phenocopies. Clinical information was obtained on all reported cases; suggested cases were investigated by biochemical or molecular analysis. RESULTS: Thirty-five of 86 reports of suggested SLOS were confirmed SLOS. Twelve infants with SLOS were born during the surveillance period, and two additional infants with SLOS were diagnosed prenatally. Twenty-one infants with SLOS were born before the onset of surveillance. CONCLUSIONS: The minimum incidence of SLOS in Canada is 1 in 70,358 live births. The minimum prevalence of SLOS is approximately 1 in 950,000. Eighteen percent of patients were mildly affected; the mean age of diagnosis of mildly affected patients was 5.3 years.     

Clinical and biochemical screening for Smith–Lemli–Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is a multiple congenital anomalies/mental retardation disorder possibly due to a defect of Δ7-sterol reductase, leading to low plasma cholesterol levels and to the accumulation of 7-dehydrocholesterol (7-DHC) and other cholesterol precursors. This study aimed to identify clinical features that could potentially be specific indicators for the clinical diagnosis of SLOS, and to test the reliability of ultraviolet spectrophotometry (UVS) as a biochemical screening procedure for the syndrome. Twenty patients with clinical suspicion of SLOS, referred to 11 Italian paediatricand clinical genetic centres, were collected during 1994. In 10 patients the diagnosis was confirmed biochemically by gas chromatography/mass spectrometry (GC/MS) analysis of serum sterols, whereas in the other 10 patients the serum sterol profiles were normal. A comparison between confirmed SLOS patients and biochemically negative subjects did not show clinical signs specific for the syndrome. UVS measurement of 7-DHC correlated well with GC/MS profiles, showing 100% sensitivity and specificity. Four out of five patients had serum bile acid concentrations below the normal range of controls.     

Clinical biochemical genetics in the twenty-first century

Genetic disorders are recognized to play an increasing role in pediatrics. Close to 10% of diseases among hospitalized children have been ascribed to Mendelian traits inherited as single gene defects, not a surprising figure considering that approximately 1000 inborn errors of metabolism (IEM) have been identified to date, primarily through the detection of endogenous metabolites abnormally accumulated in biological fluids and tissues. The laboratory discipline that covers the biochemical diagnosis of IEM is known as clinical biochemical genetics, and is defined as one concerned with the evaluation and diagnosis of patients and families with inherited metabolic disease, monitoring of treatment, and distinguishing heterozygous carriers from non-carriers by metabolite and enzymic analysis of physiological fluids and tissues. The biochemical genetics laboratory differs from the clinical chemistry laboratory in the extent of interpretation necessary to make its results meaningful to the clinician. While dramatic advances in molecular genetics have greatly changed the landscape of diagnostic options for many genetic disorders, a biochemical approach remains the dominant force for the diagnosis and monitoring of IEM. Owing to the stereotypical clinical presentation of many of these disorders, a major role of the biochemical genetics laboratory is to analyze ever more complex metabolic profiles to reach a preliminary diagnosis, which then needs to be confirmed by enzymic and/or molecular studies in vitro. Accordingly, the role of biochemical genetics in the pediatric practice of the 21st century is to provide a multicomponent screening process that can be divided into four major components: (i) at-risk screening (prenatal diagnosis); (ii) newborn screening (testing of presymptomatic patients); (iii) high-risk screening (testing of symptomatic patients); and (iv) postmortem screening (metabolic autopsy). The focus of our laboratory is to apply state-of-the-art technology such as tandem mass spectrometry to bring as many as possible IEM within the boundaries of newborn screening programs, and to investigate the role played by individual disorders in maternal complications of pregnancy, pediatric acute/fulminant liver failure, and sudden and unexpected death in early life.     

Roentgenologic diagnosis of congenital hypertrophic pyloric stenosis

In 1983-1988, in the city of Minsk 196 patients with congenital hypertrophic pylorostenosis (CHRS) were under treatment. The mean CHPS incidence is 1.06 per 1,000 neonates. X-ray examination was performed in 170 cases. CHPS was excluded by error only in one case (0.5%) on day 3 of the disease. In 8 cases, compensated pylorostenosis was diagnosed. It was characterized by proper evacuation from the stomach and positive dynamics of the body weight at the moment of examination. It is suggested that CHPS develops in response to the enhancement of hydrochloric acid secretion. The study points to the high efficacy, simplicity and safety of the method proposed.     

Infantile Refsum disease: deficiency of catalase-containing particles (peroxisomes), alkyldihydroxyacetone phosphate synthase and peroxisomal β-oxidation enzyme proteins

In recent years a number of biochemical abnormalities have been described in patients with the infantile form of Refsum disease, including the accumulation of very long chain fatty acids, trihydroxycoprostanoic acid and pipecolic acid. In this paper we show that catalase-containing particles (peroxisomes), alkyl dihydroxyacetone phosphate synthase and acyl-CoA oxidase protein are deficient in patients with infantile Refsum disease. These findings suggest that in the infantile form of Refsum disease, as in the cerebro-hepato-renal (Zellweger) syndrome the multiplicity of biochemical abnormalities is due to a deficiency of peroxisomes and hence to a generalized loss of peroxisomal functions. As a consequence the infantile form of Refsum disease can be diagnozed biochemically by methods already available for the prenatal and postnatal diagnosis of the cerebro-hepato-renal (Zellweger) syndrome.