miR-505-3p controls chemokine receptor up-regulation in macrophages: role in familial hypercholesterolemia.

Familial hypercholesterolemia (FH) conveys a high risk of premature atherosclerosis as a result of lifelong exposure to high LDL cholesterol levels that are not fully reduced by standard-of-care lipid-lowering treatment. Inflammatory mediators have played a role in the progression of atherosclerotic lesions. Here, we investigated whether innate immunity cells in patients with FH have a specific proinflammatory phenotype that is distinct from that of cells in normal participants. To this end, miR-505-3p-a microRNA related to chronic inflammation-and its target genes were investigated in monocyte-derived macrophages (MACs) of patients with FH (FH-MACs) and non-FH controls (co-MACs). On the basis of the profiler PCR array analysis of agomiR-505-3p-transfected MACs, we identified the chemokine receptors, CCR3, CCR4, and CXCR1, as genes that are regulated by miR-505-3p via the transcription factor, RUNX1. miR-505-3p was significantly down-regulated, whereas CCR3, CCR4, CXCR, and RUNX1 were increased in FH-MAC compared with co-MAC, with the increase being more evident in the proinflammatory M1-like FH-MAC. Chemokine receptor levels were unrelated to LDL plasma levels at entry, but correlated with age in patients with FH, not in controls. In summary, we demonstrate for first time to our knowledge that MACs from FH-MACs have an inflammatory phenotype that is characterized by the up-regulation of CCR3, CCR4, and CXCR1 under the control of miR-505-3p. These results suggest a chronic inflammatory condition in FH innate immunity cells that is not reverted by standard lipid-lowering treatment.-Escate, R., Mata, P., Cepeda, J. M., Padró, T., Badimon, L. miR-505-3p controls chemokine receptor up-regulation in macrophages: role in familial hypercholesterolemia.

Childhood Sex-Typed Behavior and Gender Change in Individuals with 46,XY and 46,XX Disorders of Sex Development: An Iranian Multicenter Study.

Disorders of sex development (DSD) are congenital conditions in which the typical genetic and hormonal profiles are affected and thereby the usual process of sexual differentiation. Most of these studies, however, have been conducted in Western countries. In the present study, preschool sex-typed activities of Iranian individuals with DSD and their age-matched non-affected male and female relatives were assessed using the Pre-School Activities Inventory (PSAI) modified for retrospective self-report. A total of 192 individuals participated in our study, including 33 46,XX individuals with congenital adrenal hyperplasia (CAH; M age = 10.36, SD = 5.52), 15 46,XY individuals with complete androgen insensitivity syndrome (CAIS; M age = 19.8, SD = 7.14), and 16 46,XY individuals with 5-alpha reductase deficiency type-2 (5α-RD-2; M age = 17.31, SD = 7.28), as well as one age-matched non-affected male and female relative for each patient. With regard to PSAI scores, male-identifying participants with 5α-RD-2 and male controls reported similar levels of male-typical childhood play. Female-identifying participants with 5α-RD-2 and CAH showed comparable scores: significantly less masculine and more feminine than male controls, but significantly more masculine and less feminine than females with CAIS and female controls. These findings support the role of androgens in the development of sex-typical childhood play behavior, with those being exposed to higher levels of fetal functional androgens expressing more masculine behavior at preschool ages.

ACOX2 deficiency: An inborn error of bile acid synthesis identified in an adolescent with persistent hypertransaminasemia.

BACKGROUND & AIMS: Acyl-CoA oxidase (ACOX2) is involved in the shortening of C27 cholesterol derivatives to generate C24 bile acids. Inborn errors affecting the rest of peroxisomal enzymes involved in bile acid biosynthesis have been described. Here we aimed at investigating the case of an adolescent boy with persistent hypertransaminasemia of unknown origin and suspected dysfunction in bile acid metabolism. METHODS: Serum and urine samples were taken from the patient, his sister and parents and underwent HPLC-MS/MS and HPLC-TOF analyses. Coding exons in genes of interest were amplified by high-fidelity PCR and sequenced. Wild-type or mutated (mutACOX2) variants were overexpressed in human hepatoblastoma HepG2 cells to determine ACOX2 enzymatic activity, expression and subcellular location. RESULTS: The patient's serum and urine showed negligible amounts of C24 bile acids, but augmented levels of C27 intermediates, mainly tauroconjugated trihydroxycholestanoic acid (THCA). Genetic analysis of enzymes potentially involved revealed a homozygous missense mutation (c.673C>T; R225W) in ACOX2. His only sister was also homozygous for this mutation and exhibited similar alterations in bile acid profiles. Both parents were heterozygous and presented normal C24 and C27 bile acid levels. Immunofluorescence studies showed similar protein size and peroxisomal localization for both normal and mutated variants. THCA biotransformation into cholic acid was enhanced in cells overexpressing ACOX2, but not in those overexpressing mutACOX2. Both cell types showed similar sensitivity to oxidative stress caused by C24 bile acids. In contrast, THCA-induced oxidative stress and cell death were reduced by overexpressing ACOX2, but not mutACOX2. CONCLUSION: ACOX2 deficiency, a condition characterized by accumulation of toxic C27 bile acid intermediates, is a novel cause of isolated persistent hypertransaminasemia. LAY SUMMARY: Elevation of serum transaminases is a biochemical sign of liver damage due to multiplicity of causes (viruses, toxins, autoimmunity, metabolic disorders). In rare cases the origin of this alteration remains unknown. We have identified by the first time in a young patient and his only sister a familiar genetic defect of an enzyme called ACOX2, which participates in the transformation of cholesterol into bile acids as a cause of increased serum transaminases in the absence of any other symptomatology. This treatable condition should be considered in the diagnosis of those patients where the cause of elevated transaminases remains obscure.

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 ·â€Škg ·â€Šday. 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.

Impaired Hepatic Uptake by Organic Anion-Transporting Polypeptides Is Associated with Hyperbilirubinemia and Hypercholanemia in Atp11c Mutant Mice.

Biliary excretion of organic anions, such as bile acids (BAs), is the main osmotic driving force for bile formation, and its impairment induces intrahepatic cholestasis. We investigated the involvement of Atp11c in the hepatic transport of organic anions using Atp11c mutant mice, which exhibit hypercholanemia and hyperbilirubinemia. Pharmacokinetic analysis following a constant intravenous infusion in Atp11c mutant mice showed decreased hepatic sinusoidal uptake and intact biliary secretion of [(3)H]17ß estradiol 17ß-d-glucuronide. Consistent with this result, compared with cells and membranes from control mice, isolated hepatocytes, and liver plasma membranes from Atp11c mutant mice had a much lower uptake of [(3)H]17ß estradiol 17ß-d-glucuronide and expression of organic anion-transporting polypeptides, which are transporters responsible for hepatic uptake of unconjugated BAs and organic anions, including bilirubin glucuronides. Uptake of [(3)H]TC into hepatocytes and expression of Na(+)-taurocholate cotransporting polypeptide in liver plasma membranes, which mediates hepatic uptake of conjugated BAs, was also lower in the Atp11c mutant mice. Bile flow rate, biliary BA concentration, and expression of hepatobiliary transporters did not differ between Atp11c mutant mice and control mice. These results suggest that Atp11c mediates the transport of BAs and organic anions across the sinusoidal membrane, but not the canalicular membrane, by regulating the abundance of transporters. Atp11c is a candidate gene for genetically undiagnosed cases of hypercholanemia and hyperbilirubinemia, but not of intrahepatic cholestasis. This gene may influence the pharmacological and adverse effect of drugs because organic anion-transporting polypeptides regulate their systemic exposure.

Liver transplantation in defects of cholesterol biosynthesis: the case of lathosterolosis.

We report the outcome of liver transplantation (LT) in the only surviving patient with lathosterolosis, a defect of cholesterol biosynthesis characterized by high lathosterol levels associated with progressive cholestasis, multiple congenital anomalies and mental retardation. From her diagnosis at age 2 she had shown autistic behavior, was unable to walk unaided and her sight was impaired by cataracts. By age 7 she developed end-stage liver disease. After a soul-searching discussion within the transplantation team, she was treated with LT as this represented her only lifesaving option. At 1-year follow-up, her lathosterol levels had returned to normal (0.61 mg/dL from 13.04 ± 2.65) and her nutrition improved. She began exploring her environment and walking by holding onto an adult's hand and then independently. Her brain magnetic resonance imaging (MRI) had shown a normal picture at age 1, whereas a volume reduction of white matter with ex vacuo ventricular dilatation and defective myelinization were observed before transplant. At 5-year follow-up, a complete biochemical recovery, an arrest of mental deterioration and a stable MRI picture were achieved, with a return to her every day life albeit with limitations. Timely liver transplant in defects of cholesterol biosynthesis might arrest the progression of neurological damage.

Recognition of asymptomatic hypercholanemia of pregnancy: Different clinical features, fetal outcomes and bile acids metabolism from intrahepatic cholestasis of pregnancy.

OBJECTIVE: To explore the clinical features, fetal outcomes and serum bile acids (BAs) metabolism in asymptomatic hypercholanemia of pregnancy (AHP), as well as the comparison with those in intrahepatic cholestasis of pregnancy (ICP) and normal pregnancies. METHODS: A study containing 676 pregnant women was performed to investigate the clinical informations, routine biochemical features and obstetric outcomes of AHP by the comparison with ICP and normal pregnancies. Within the study subjects, 203 pregnant women received prospective determination for 55 serum individual BAs based on a validated UPLC-QTOF-MS/MS method. The differences in clinical features and serum BAs metabolism among the three groups were then investigated. RESULTS: The risk of adverse fetal outcomes in AHP (28.3%) was significantly higher than that in normal pregnancies (8.9%, p < 0.001), but lower than that in ICP group (52.1%, p < 0.001). Multivariate statistics analysis indicated a distinctive serum BAs metabolic profiling among the three groups (PLS-DA, R2Y = 0.580, Q2 = 0.537). Levels of serum BAs especially for deoxycholic acid species were found remarkably elevated in AHP as compared to those in ICP. CONCLUSIONS: AHP group had distinguished clinical features and serum BAs metabolism as compared to ICP group and normal pregnancies.

Emerging roles of melanocortin receptor accessory proteins (MRAP and MRAP2) in physiology and pathophysiology.

Melanocortin-2 receptor accessory protein (MRAP) has an unusual dual topology and influences the expression, localisation, signalling and internalisation of the melanocortin receptor 2 (MC2); the adrenocorticotropic hormone (ACTH) receptor. Mutations in MRAP are associated with familial glucocorticoid deficiency type-2 and evidence is emerging of the importance of MRAP in adrenal development and ACTH signalling. Human MRAP has two functional splice variants: MRAP-α and MRAP-ß, unlike MRAP-ß, MRAP-α has little expression in brain but is highly expressed in ovary. MRAP2, identified through whole human genome sequence analysis, has approximately 40% sequence homology to MRAP. MRAP2 facilitates MC2 localisation to the cell surface but not ACTH signalling. MRAP and MRAP2 have been found to regulate the surface expression and signalling of all melanocortin receptors (MC1-5). Additionally, MRAP2 moderates the signalling of the G-protein coupled receptors (GCPRs): orexin, prokineticin and GHSR1a; the ghrelin receptor. Whilst MRAP appears to be mainly involved in glucocorticoid synthesis, an important role is emerging for MRAP2 in regulating appetite and energy homeostasis. Transgenic models indicate the importance of MRAP in adrenal gland formation. Like MC3R and MC4R knockout mice, MRAP2 knockout mice have an obese phenotype. In vitro studies indicate that MRAP2 enhances the MC3 and MC4 response to the agonist αMSH, which, like ACTH, is produced through precursor polypeptide proopiomelanocortin (POMC) cleavage. Analysis of cohorts of individuals with obesity have revealed several MRAP2 genetic variants with loss of function mutations which are causative of monogenic hyperphagic obesity with hyperglycaemia and hypertension. MRAP2 may also be associated with female infertility. This review summarises current knowledge of MRAP and MRAP2, their influence on GPCR signalling, and focusses on pathophysiology, particularly familial glucocorticoid deficiency type-2 and obesity.

Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism.

Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.

Isolated glucocorticoid deficiency: Genetic causes and animal models.

Hereditary adrenocorticotropin (ACTH) resistance syndromes encompass the genetically heterogeneous isolated or Familial Glucocorticoid Deficiency (FGD) and the distinct clinical entity known as Triple A syndrome. The molecular basis of adrenal resistance to ACTH includes defects in ligand binding, MC2R/MRAP receptor trafficking, cellular redox balance, cholesterol synthesis and sphingolipid metabolism. Biochemically, this manifests as ACTH excess in the setting of hypocortisolaemia. Triple A syndrome is an inherited condition involving a tetrad of adrenal insufficiency, achalasia, alacrima and neuropathy. FGD is an autosomal recessive condition characterized by the presence of isolated glucocorticoid deficiency, classically in the setting of preserved mineralocorticoid secretion. Primarily there are three established subtypes of the disease: FGD 1, FGD2 and FGD3 corresponding to mutations in the Melanocortin 2 receptor MC2R (25%), Melanocortin 2 receptor accessory protein MRAP (20%), and Steroidogenic acute regulatory protein STAR (5-10%) respectively. Together, mutations in these 3 genes account for approximately half of cases. Whole exome sequencing in patients negative for MC2R, MRAP and STAR mutations, identified mutations in minichromosome maintenance 4 MCM4, nicotinamide nucleotide transhydrogenase NNT, thioredoxin reductase 2 TXNRD2, cytochrome p450scc CYP11A1, and sphingosine 1-phosphate lyase SGPL1 accounting for a further 10% of FGD. These novel genes have linked replicative and oxidative stress and altered redox potential as a mechanism of adrenocortical damage. However, a genetic diagnosis is still unclear in about 40% of cases. We describe here an updated list of FGD genes and provide a description of relevant mouse models that, despite some being flawed, have been precious allies in the understanding of FGD pathobiology.

Enzymes in the conversion of cholesterol into bile acids.

This article aims to give an overview on the characterization, properties and regulation of enzymes, particularly the cytochrome (CYP) P450 enzymes, in the formation of bile acids from cholesterol. Bile acids are biologically active molecules that promote absorption of dietary lipids in the intestine and stimulate biliary excretion of cholesterol. Bile acids and oxysterols, formed from cholesterol, act as ligands to nuclear receptors regulating the expression of important genes in cholesterol homeostasis. Thus, the bioactivation of cholesterol into bile acids is crucial for regulation of cholesterol homeostasis. The primary human bile acids, cholic acid and chenodeoxycholic acid, are formed from cholesterol via several pathways involving many different enzymes. Many of these enzymes are cytochrome P450 (CYP) enzymes, introducing a hydroxyl group in the molecule. The "classic" pathway of bile acid formation starts with a 7alpha-hydroxylation of cholesterol by CYP7A1 in the liver. The "acidic" pathway starts with a hepatic or extrahepatic 27-hydroxylation by CYP27A1. There also exist some quantitatively minor pathways which may be of importance under certain conditions. Formation of cholic acid requires insertion of a 12alpha-hydroxyl group performed by CYP8B1. Oxysterols are precursors to bile acids, participate in cholesterol transport and are known to affect the expression of several genes in cholesterol homeostasis. Enzymes with capacity to form and metabolize oxysterols are present in liver and extrahepatic tissues. The enzymes, nuclear receptors and transcription factors involved in bile acid biosynthesis are potential pharmaceutical targets for the development of new drugs to control hypercholesterolemia and to prevent atherosclerosis and other diseases related to disturbed cholesterol homeostasis. The review will also discuss some inborn errors of bile acid biosynthesis and the recently acquired knowledge on the genetic defects underlying these diseases.

46,XY Disorder of Sex Development due to 17-Beta Hydroxysteroid Dehydrogenase Type 3 Deficiency in an Infant of Greek Origin.

17-beta hydroxysteroid dehydrogenase type 3 (17ßHSD-3) enzyme catalyzes the conversion of androstenedione (Δ4) to testosterone (T) in the testes of the developing fetus, thus playing a crucial role in the differentiation of the gonads and in establishing the male sex phenotype. Any mutation in the encoding gene (HSD17B3) can lead to varying degrees of undervirilization of the affected male, ranging from completely undervirilized external female genitalia to predominantly male with micropenis and hypospadias. We present here an infant who was referred to our clinic because of ambiguous genitalia at birth. Gonads were palpable in the inguinal canal bilaterally and no Müllerian structures were identified on pelvic ultrasound. Because of a low T/Δ4 ratio after a human chorionic gonadotropin stimulation test, a tentative diagnosis of 17ßHSD-3 deficiency was made which was confirmed after genetic analysis of the HSD17B3 gene of the patient. The molecular analysis identified compound heterozygosity of two previously described mutations and could offer some further validation for the idea of a founder effect for 655-1;G→A mutation in the Greek population.

Prenatal testosterone and theory of mind development: Findings from disorders of sex development.

Women on average perform better than men on the "Reading the Mind in the Eyes" test (RMET) which is a measure of Theory of Mind (ToM). The aim of this study was to assess whether these sex differences are influenced by differences in prenatal testosterone levels through a study on individuals with Disorders of Sex Development and matched controls. ToM performance was examined using the RMET in female-assigned-at-birth individuals with increased prenatal testosterone exposure (Congenital Adrenal Hyperplasia (CAH) and 5-alpha Reductase type-2 Deficiency (5α-RD-2)), female-assigned-at-birth individuals with testosterone insensitivity (Complete Androgen Insensitivity Syndrome (CAIS)), and their age-matched unaffected male and female relatives. A total number of 158 individuals participated in the study; 19 with 5α-RD-2, 17 with CAH, 18 women with CAIS, 52 matched unaffected men and 52 matched unaffected women. All subgroups were around 20 years of age. Women with CAH scored significantly lower on RMET than control women and CAIS individuals. CAIS individuals scored significantly higher than control men and participants with 5α-RD. Statistically, CAIS individuals' performance on RMET was similar to control women's, women with CAH did not differ significantly from control men and 5α-RD-2 individuals scored significantly lower than control men. These results, which are in line with previous theories, illustrate that performance on the RMET, as an index of ToM, may be influenced by variations in prenatal androgens levels.

Increased density of ghrelin-expressing cells in the gastric fundus and body in Prader-Willi syndrome.

CONTEXT: The levels of ghrelin, an orexigenic hormone secreted by oxyntic cells in the digestive tract, are elevated in Prader-Willi syndrome (PWS) and GH deficiency (GHD) patients. In this study, we hypothesized that the hyperghrelinemia observed in PWS is related to IGF-I or GH/IGF axis deficiency. DESIGN: We investigated the densities of ghrelin-expressing cells (GECs), the amounts of ghrelin in gastric tissues, and ghrelin levels in plasma in 16 PWS patients and compared these results with those of 13 GHD patients and comparison groups (19 normal lean and 10 normal obese subjects). RESULTS: In the gastric body and fundus, 2- to 3-fold increases in the numbers of GECs (P < 0.001) and in the amounts of ghrelin (P < 0.018) were noted in PWS patients vs. comparison groups, whereas GEC numbers in GHD patients were similar to those of the comparison group despite elevated fasting plasma ghrelin levels. In addition, IGF-I sd scores in PWS were not found to be correlated with GEC densities, the amounts of ghrelin expressed in gastric tissues, or plasma ghrelin levels. CONCLUSIONS: Our results suggest that IGF-I or GH/IGF axis deficiency appears to be unrelated to observed GEC increases in the stomach of patients with PWS.

Interdependence of lean body mass and total body water, but not quality of life measures, during low dose GH replacement in GH-deficient adults.

Lean body mass (LBM) and total body water (TBW) are reduced in GH-deficient (GHD) adults and alter with GH replacement. Whether these parameters are interdependent and whether alterations in their homeostasis contribute to the perceived quality of life (QOL) deficit in GHD remains unclear. In this study, IGF-I, body composition by whole-body dual-energy X-ray absorptiometry, TBW by deuterium dilution (D(2)O) and two validated QOL instruments - psychological general well-being schedule (PGWB, generic, 6 domains; lower score worse QOL) and assessment of GH deficiency in adults (AGHDA, disease orientated; higher score worse QOL) were studied at baseline and after 3 and 6 months of GH replacement in thirty GHD adults. Patients with diabetes insipidus, and cardiac and renal failure were excluded. Median age-adjusted IGF-I standard deviation score increased from -3.40 (-6.40 to -1.60) to -0.2 (-1.88 to 0.78) (P < 0.0001) at a median daily GH dose of 0.4 mg. During treatment, LBM increased from 47.4 +/- 10.7 kg at baseline to 49.5 +/- 10.8 kg at 6 months (P = 0.0008), and fat mass decreased from 28.0 +/- 12.1 kg at baseline to 27.2 +/- 12.6 kg at 6 months (P = 0.0004). A non-significant trend towards an increase in TBW was observed (mean 1.7 kg, P = 0.08). The PGWB score increased from 62.9 +/- 20.6 to 73.7 +/- 21.7 (P = 0.0006). The AGHDA score decreased from 13.7 +/- 7.3 to 8.75 +/- 7.75 (P = 0.0002). At each time point, a linear correlation between LBM and TBW was demonstrated, defined by TBW = (0.972 x LBM)-10.6. However, only a weakly positive correlation existed between the percentage changes in these variables (R = 0.40, P = 0.04). No correlations were demonstrated between QOL measures and body composition. The change in LBM with physiological GH replacement correlates weakly with change in TBW, therefore factors other than TBW may also contribute to the LBM changes. Improved QOL with GH replacement is not explained by favourable changes in body composition.

A particular phenotype in a girl with aldosterone synthase deficiency.

Aldosterone synthase deficiency (ASD) usually presents in infancy as a life-threatening electrolyte imbalance. A 4-wk-old child of unrelated parents was examined for failure to thrive and salt-wasting. Notable laboratory findings were hyperkalemia, high plasma renin, and low-normal aldosterone levels. Urinary metabolite ratios of corticosterone/18-hydroxycorticosterone and 18-hydroxycorticosterone/aldosterone were intermediate between ASD type I and type II. Sequence analysis of CYP11B2, the gene encoding aldosterone synthase (P450c11AS), revealed that the patient was a compound heterozygote carrying a previously described mutation located in exon 4 causing a premature stop codon (E255X) and a further, novel mutation in exon 5 that also causes a premature stop codon (Q272X). The patient's unaffected father was a heterozygous carrier of the E255X mutation, whereas the unaffected mother was a heterozygous carrier of the Q272X mutation. Therefore, the patient's CYP11B2 encodes two truncated forms of aldosterone synthase predicted to be inactive because they lack critical active site residues as well as the heme-binding site. This case of ASD is of particular interest because despite the apparent lack of aldosterone synthase activity, the patient displays low-normal aldosterone levels, thus raising the question of its source.

Apparent pregnene hydroxylation deficiency (APHD): seeking the parentage of an orphan metabolome.

This paper collates and reviews a number of clinical cases published over the last 20 years that we believe describe a novel steroid disorder associated with genital ambiguity. The authors of the original papers were unable to diagnose their patients conclusively. Females with the disorder are frequently masculinized and males feminized. The central feature of steroid biosynthesis is overproduction of pregnenolone and progesterone, which results in elevated concentrations of these steroids in plasma and exaggerated response to ACTH. Equivalent urinary data show elevated excretion of 5-pregnene-3beta,20alpha-diol (the major pregnenolone metabolite) and pregnanediol. Another notable feature of the metabolome is the relatively high plasma concentrations of the analytes for 21-hydroxylase deficiency (17-hydroxyprogesterone) and 17-hydroxylase deficiency (corticosterone). Correspondingly, metabolites of these steroids are prominent in urine. Circulating cortisol was generally normal but had blunted response to ACTH. Taken together these features pointed to an apparent relative deficiency of 21- and 17-hydroxylation, but no mutations have been found in the enzymes responsible for these transformations in cases where it has been investigated. The simultaneous presence of mutated genes on two chromosomes is also extremely unlikely. Until more is known of this interesting condition, and the genetic cause (presumed) is known, we propose naming it apparent pregnene hydroxylation deficiency (APHD). The metabolome is similar to that of isolated 17,20-lyase deficiency with which it has been confused. In fact, diminished (but not isolated) lyase activity is probably a significant factor in some patients. We believe that the attenuated steroid hydroxylation could be associated with deficiency of the required co-factors and modulators of hydroxylation such as P450 reductase and cytochrome b5. Post-translational modifications of the hydroxylases such as phosphorylation/dephosphorylation have also been suggested as influential in directionally regulating steroid synthesis. Some patients with the disorder have no dysmorphology apart from genital malformations while others have skeletal abnormalities attributed to Antley-Bixler syndrome. Whether we are looking at different conditions, or a severity continuum is not known. It is possible that the presence of this metabolome may become a required feature for diagnosis of Antley-Bixler syndrome. A combination of intersex phenotype and dysmorphology suggests that an error in a transcription factor may be an alternative to hydroxylation redox partner deficit as causative of the condition.The virilization of female patients with APHD probably results from a transient hyperandrogenism prior to birth.

ACTH resistance: genes and mechanisms.

ACTH resistance is a rare disorder typified by familial glucocorticoid deficiency (FGD), a genetically heterogeneous disease. Previously, genetic defects in FGD have been identified in the ACTH receptor gene (MC2R), its accessory protein (MRAP) and the steroidogenic acute regulatory protein gene (STAR). The defective mechanisms here are failures in ACTH ligand binding and/or receptor trafficking for MC2R and MRAP and, in the case of STAR mutations, inefficient cholesterol transport to allow steroidogenesis to proceed. Novel gene defects in FGD have recently been recognised in mini-chromosome maintenance-deficient 4 homologue (MCM4) and nicotinamide nucleotide transhydrogenase (NNT). MCM4 is one part of a DNA repair complex essential for DNA replication and genome stability, whilst NNT is involved in the glutathione redox system that protects cells against reactive oxygen species. The finding of mutations in these two genes implicates new pathogenetic mechanisms at play in FGD, and implies that the adrenal cortex is exquisitely sensitive to replicative and oxidative stresses.

Sterol metabolism disorders and neurodevelopment-an update.

Cholesterol has numerous quintessential functions in normal cell physiology, as well as in embryonic and postnatal development. It is a major component of cell membranes and myelin, and is a precursor of steroid hormones and bile acids. The development of the blood brain barrier likely around 12-18 weeks of human gestation makes the developing embryonic/fetal brain dependent on endogenous cholesterol synthesis. Known enzyme defects along the cholesterol biosynthetic pathway result in a host of neurodevelopmental and behavioral findings along with CNS structural anomalies. In this article, we review sterol synthesis disorders in the pre- and post-squalene pathway highlighting neurodevelopmental aspects that underlie the clinical presentations and course of Smith-Lemli-Opitz Syndrome (SLOS), mevalonic aciduria (MVA) or the milder version hyper-immunoglobulinemia D and periodic fever syndrome (HIDS), Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis (ABS1), congenital hemidysplasia with icthyosiform nevus and limb defects (CHILD) syndrome, CK syndrome, sterol C4 methyl oxidase (SC4MOL) deficiency, X-linked dominant chondrodysplasia punctata 2(CDPX2)/ Conradi Hunermann syndrome, lathosterolosis and desmosterolosis, We also discuss current controversies and share thoughts on future directions in the field.