Barth syndrome with severe dilated cardiomyopathy and growth hormone resistance: a case report.

OBJECTIVES: To describe the metabolic and endocrine features of a patient with Barth syndrome who showed evidence of growth hormone resistance. CASE PRESENTATION: A male proband deteriorated rapidly with lactic acidosis after a circumcision at age three weeks and was found to have severe dilated cardiomyopathy. A cardiomyopathy gene panel led to the diagnosis of TAZ-deficiency Barth syndrome. He subsequently experienced hypotonia and gross motor delay, feeding difficulties for the first four years, constitutional growth delay and one episode of ketotic hypoglycaemia. Cardiomyopathy resolved on oral anti-failure therapy by age three years. He had a hormonal pattern of growth hormone resistance, and growth hormone treatment was considered, however height velocity improved spontaneously after age 3½ years. He also had biochemical primary hypothyroidism. CONCLUSIONS: With careful metabolic management with l-arginine supplementation, overnight corn starch, and a prescribed exercise program, our patient's strength, endurance, level of physical activity and body composition improved significantly by age six years.

A Pilot Study of Bioenergetic Marker Relationships in Gulf War Illness: Phosphocreatine Recovery vs. Citric Acid Cycle Intermediates.

Impaired bioenergetics have been reported in veterans with Gulf War illness (VGWIs), including prolonged post-exercise recovery of phosphocreatine (PCr-R) assessed with 31Phosphorus magnetic resonance spectroscopy. The citric acid cycle (CAC) is considered the most important metabolic pathway for supplying energy, with relationships among CAC markers reported to shift in some but not all impaired bioenergetic settings. We sought to assess relations of CAC markers to one another and to PCr-R. Participants were 33 VGWIs and 33 healthy controls 1:1 matched on age-sex-ethnicity. We assessed seven CAC intermediates, and evaluated PCr-R in a subset of matched case-control pairs (N = 14). CAC markers did not significantly differ between cases and controls. Relationships of alpha-ketoglutarate to malate, isocitrate, and succinate were strongly significant in cases with materially weaker relationships in controls, suggesting possible shifts in these markers in concert in VGWIs. PCr-R correlated strongly with five of seven CAC markers in controls (succinate, malate, fumarate, citrate, isocitrate, range r = -0.74 to -0.88), but bore no relationship in VGWIs. In summary, PCr-R related significantly to CAC markers in healthy controls, but not VGWIs. In contrast, relations of CAC markers to one another appeared to shift (often strengthen) in VGWIs.

A placebo-controlled trial of simvastatin therapy in Smith-Lemli-Opitz syndrome.

BACKGROUND: Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation/cognitive impairment syndrome characterized by the accumulation of 7-dehydrocholesterol, a precursor sterol of cholesterol. Simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor that crosses the blood-brain barrier, has been proposed for the treatment of SLOS based on in vitro and in vivo studies suggesting that simvastatin increases the expression of hypomorphic DHCR7 alleles. METHODS: Safety and efficacy of simvastatin therapy in 23 patients with mild to typical SLOS were evaluated in a randomized, double-blind, placebo-controlled trial. The crossover trial consisted of two 12-month treatment phases separated by a 2-month washout period. RESULTS: No safety issues were identified in this study. Plasma dehydrocholesterol concentrations decreased significantly: 8.9 ± 8.4% on placebo to 6.1 ± 5.5% on simvastatin (P < 0.005); we observed a trend toward decreased cerebrospinal fluid dehydrocholesterol concentrations. A significant improvement (P = 0.017, paired t-test) was observed on the irritability subscale of the Aberrant Behavior Checklist-C when subjects were taking simvastatin. CONCLUSION: This article reports what is, to our knowledge, the first randomized, placebo-controlled trial designed to test the safety and efficacy of simvastatin therapy in SLOS. Simvastatin seems to be relatively safe in patients with SLOS, improves the serum dehydrocholesterol-to-total sterol ratio, and significantly improves irritability symptoms in patients with mild to classic SLOS.Genet Med 19 3, 297-305.

Altered cholesterol biosynthesis causes precocious neurogenesis in the developing mouse forebrain.

We previously reported a mutation in the cholesterol biosynthesis gene, hydroxysteroid (17-beta) dehydrogenase 7 (Hsd17b7(rudolph)), that results in striking embryonic forebrain dysgenesis. Here we describe abnormal patterns of neuroprogenitor proliferation in the mutant forebrain, namely, a decrease in mitotic cells within the ventricular zone (VZ) and an increase through the remainder of the cortex by E11.5. Further evidence suggests mutant cells undergo abnormal interkinetic nuclear migration (IKNM). Furthermore, intermediate progenitors are increased at the expense of apical progenitors by E12.5, and post-mitotic neurons are expanded by E14.5. In vitro primary neuron culture further supports our model of accelerated cortical differentiation in the mutant. Combined administration of a statin and dietary cholesterol in utero achieved partial reversal of multiple developmental abnormalities in the Hsd17b7(rudolph) embryo, including the forebrain. These results suggest that abnormally increased levels of specific cholesterol precursors in the Hsd17b7(rudolph) embryo cause cortical dysgenesis by altering patterns of neurogenesis.

Modeling the mitochondrial cardiomyopathy of Barth syndrome with induced pluripotent stem cell and heart-on-chip technologies.

Study of monogenic mitochondrial cardiomyopathies may yield insights into mitochondrial roles in cardiac development and disease. Here, we combined patient-derived and genetically engineered induced pluripotent stem cells (iPSCs) with tissue engineering to elucidate the pathophysiology underlying the cardiomyopathy of Barth syndrome (BTHS), a mitochondrial disorder caused by mutation of the gene encoding tafazzin (TAZ). Using BTHS iPSC-derived cardiomyocytes (iPSC-CMs), we defined metabolic, structural and functional abnormalities associated with TAZ mutation. BTHS iPSC-CMs assembled sparse and irregular sarcomeres, and engineered BTHS 'heart-on-chip' tissues contracted weakly. Gene replacement and genome editing demonstrated that TAZ mutation is necessary and sufficient for these phenotypes. Sarcomere assembly and myocardial contraction abnormalities occurred in the context of normal whole-cell ATP levels. Excess levels of reactive oxygen species mechanistically linked TAZ mutation to impaired cardiomyocyte function. Our study provides new insights into the pathogenesis of Barth syndrome, suggests new treatment strategies and advances iPSC-based in vitro modeling of cardiomyopathy.

Clinical laboratory studies in Barth Syndrome.

Barth Syndrome is a rare X-linked disorder characterized principally by dilated cardiomyopathy, skeletal myopathy and neutropenia and caused by defects in tafazzin, an enzyme responsible for modifying the acyl chain moieties of cardiolipin. While several comprehensive clinical studies of Barth Syndrome have been published detailing cardiac and hematologic features, descriptions of its biochemical characteristics are limited. To gain a better understanding of the clinical biochemistry of this rare disease, we measured hematologic and biochemical values in a cohort of Barth Syndrome patients. We characterized multiple biochemical parameters, including plasma amino acids, plasma 3-methylglutaconic acid, cholesterol, cholesterol synthetic intermediates, and red blood cell membrane fatty acid profiles in 28 individuals with Barth Syndrome from ages 10 months to 30 years. We describe a unique biochemical profile for these patients, including decreased plasma arginine levels. We further studied the plasma amino acid profiles, cholesterol, cholesterol synthetic intermediates, and plasma 3-methylglutaconic acid levels in 8 female carriers and showed that they do not share any of the distinct, Barth Syndrome-specific biochemical laboratory abnormalities. Our studies augment and expand the biochemical profiles of individuals with Barth Syndrome, describe a unique biochemical profile for these patients, and provide insight into the possible underlying biochemical pathology in this disorder.

Severity of cardiomyopathy associated with adenine nucleotide translocator-1 deficiency correlates with mtDNA haplogroup.

Mutations of both nuclear and mitochondrial DNA (mtDNA)-encoded mitochondrial proteins can cause cardiomyopathy associated with mitochondrial dysfunction. Hence, the cardiac phenotype of nuclear DNA mitochondrial mutations might be modulated by mtDNA variation. We studied a 13-generation Mennonite pedigree with autosomal recessive myopathy and cardiomyopathy due to an SLC25A4 frameshift null mutation (c.523delC, p.Q175RfsX38), which codes for the heart-muscle isoform of the adenine nucleotide translocator-1. Ten homozygous null (adenine nucleotide translocator-1(-/-)) patients monitored over a median of 6 years had a phenotype of progressive myocardial thickening, hyperalaninemia, lactic acidosis, exercise intolerance, and persistent adrenergic activation. Electrocardiography and echocardiography with velocity vector imaging revealed abnormal contractile mechanics, myocardial repolarization abnormalities, and impaired left ventricular relaxation. End-stage heart disease was characterized by massive, symmetric, concentric cardiac hypertrophy; widespread cardiomyocyte degeneration; overabundant and structurally abnormal mitochondria; extensive subendocardial interstitial fibrosis; and marked hypertrophy of arteriolar smooth muscle. Substantial variability in the progression and severity of heart disease segregated with maternal lineage, and sequencing of mtDNA from five maternal lineages revealed two major European haplogroups, U and H. Patients with the haplogroup U mtDNAs had more rapid and severe cardiomyopathy than those with haplogroup H.

Barth syndrome.

First described in 1983, Barth syndrome (BTHS) is widely regarded as a rare X-linked genetic disease characterised by cardiomyopathy (CM), skeletal myopathy, growth delay, neutropenia and increased urinary excretion of 3-methylglutaconic acid (3-MGCA). Fewer than 200 living males are known worldwide, but evidence is accumulating that the disorder is substantially under-diagnosed. Clinical features include variable combinations of the following wide spectrum: dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), endocardial fibroelastosis (EFE), left ventricular non-compaction (LVNC), ventricular arrhythmia, sudden cardiac death, prolonged QTc interval, delayed motor milestones, proximal myopathy, lethargy and fatigue, neutropenia (absent to severe; persistent, intermittent or perfectly cyclical), compensatory monocytosis, recurrent bacterial infection, hypoglycaemia, lactic acidosis, growth and pubertal delay, feeding problems, failure to thrive, episodic diarrhoea, characteristic facies, and X-linked family history. Historically regarded as a cardiac disease, BTHS is now considered a multi-system disorder which may be first seen by many different specialists or generalists. Phenotypic breadth and variability present a major challenge to the diagnostician: some children with BTHS have never been neutropenic, whereas others lack increased 3-MGCA and a minority has occult or absent CM. Furthermore, BTHS was first described in 2010 as an unrecognised cause of fetal death. Disabling mutations or deletions of the tafazzin (TAZ) gene, located at Xq28, cause the disorder by reducing remodeling of cardiolipin, a principal phospholipid of the inner mitochondrial membrane. A definitive biochemical test, based on detecting abnormal ratios of different cardiolipin species, was first described in 2008. Key areas of differential diagnosis include metabolic and viral cardiomyopathies, mitochondrial diseases, and many causes of neutropenia and recurrent male miscarriage and stillbirth. Cardiolipin testing and TAZ sequencing now provide relatively rapid diagnostic testing, both prospectively and retrospectively, from a range of fresh or stored tissues, blood or neonatal bloodspots. TAZ sequencing also allows female carrier detection and antenatal screening. Management of BTHS includes medical therapy of CM, cardiac transplantation (in 14% of patients), antibiotic prophylaxis and granulocyte colony-stimulating factor (G-CSF) therapy. Multidisciplinary teams/clinics are essential for minimising hospital attendances and allowing many more individuals with BTHS to live into adulthood.

Targeting C4-demethylating genes in the cholesterol pathway sensitizes cancer cells to EGF receptor inhibitors via increased EGF receptor degradation.

UNLABELLED: Persistent signaling by the oncogenic EGF receptor (EGFR) is a major source of cancer resistance to EGFR targeting. We established that inactivation of 2 sterol biosynthesis pathway genes, SC4MOL (sterol C4-methyl oxidase-like) and its partner, NSDHL (NADP-dependent steroid dehydrogenase-like), sensitized tumor cells to EGFR inhibitors. Bioinformatics modeling of interactions for the sterol pathway genes in eukaryotes allowed us to hypothesize and then extensively validate an unexpected role for SC4MOL and NSDHL in controlling the signaling, vesicular trafficking, and degradation of EGFR and its dimerization partners, ERBB2 and ERBB3. Metabolic block upstream of SC4MOL with ketoconazole or CYP51A1 siRNA rescued cancer cell viability and EGFR degradation. Inactivation of SC4MOL markedly sensitized A431 xenografts to cetuximab, a therapeutic anti-EGFR antibody. Analysis of Nsdhl-deficient Bpa(1H/+) mice confirmed dramatic and selective loss of internalized platelet-derived growth factor receptor in fibroblasts, and reduced activation of EGFR and its effectors in regions of skin lacking NSDHL. SIGNIFICANCE: This work identifies a critical role for SC4MOL and NSDHL in the regulation of EGFR signaling and endocytic trafficking and suggests novel strategies to increase the potency of EGFR antagonists in tumors.

Deficiency for the ubiquitin ligase UBE3B in a blepharophimosis-ptosis-intellectual-disability syndrome.

Ubiquitination plays a crucial role in neurodevelopment as exemplified by Angelman syndrome, which is caused by genetic alterations of the ubiquitin ligase-encoding UBE3A gene. Although the function of UBE3A has been widely studied, little is known about its paralog UBE3B. By using exome and capillary sequencing, we here identify biallelic UBE3B mutations in four patients from three unrelated families presenting an autosomal-recessive blepharophimosis-ptosis-intellectual-disability syndrome characterized by developmental delay, growth retardation with a small head circumference, facial dysmorphisms, and low cholesterol levels. UBE3B encodes an uncharacterized E3 ubiquitin ligase. The identified UBE3B variants include one frameshift and two splice-site mutations as well as a missense substitution affecting the highly conserved HECT domain. Disruption of mouse Ube3b leads to reduced viability and recapitulates key aspects of the human disorder, such as reduced weight and brain size and a downregulation of cholesterol synthesis. We establish that the probable Caenorhabditis elegans ortholog of UBE3B, oxi-1, functions in the ubiquitin/proteasome system in vivo and is especially required under oxidative stress conditions. Our data reveal the pleiotropic effects of UBE3B deficiency and reinforce the physiological importance of ubiquitination in neuronal development and function in mammals.

A homozygous missense mutation in HERC2 associated with global developmental delay and autism spectrum disorder.

We studied a unique phenotype of cognitive delay, autistic behavior, and gait instability segregating in three separate sibships. We initiated genome-wide mapping in two sibships using Affymetrix 10K SNP Mapping Arrays and identified a homozygous 8.2 Mb region on chromosome 15 common to five affected children. We used exome sequencing of two affected children to assess coding sequence variants within the mapped interval. Four novel homozygous exome variants were shared between the two patients; however, only two variants localized to the mapped interval on chromosome 15. A third sibship in an Ohio Amish deme narrowed the mapped interval to 2.6 Mb and excluded one of the two novel homozygous exome variants. The remaining variant, a missense change in HERC2 (c.1781C>T, p.Pro594Leu), occurs in a highly conserved proline residue within an RCC1-like functional domain. Functional studies of truncated HERC2 in adherent retinal pigment epithelium cells suggest that the p.Pro594Leu variant induces protein aggregation and leads to decreased HERC2 abundance. The phenotypic correlation with the mouse Herc1 and Herc2 mutants as well as the phenotypic overlap with Angelman syndrome provide further evidence that pathogenic changes in HERC2 are associated with nonsyndromic intellectual disability, autism, and gait disturbance. Hum Mutat 33:1639-1646, 2012. © 2012 Wiley Periodicals, Inc.

Hepatitis C virus selectively perturbs the distal cholesterol synthesis pathway in a genotype-specific manner.

UNLABELLED: Hepatitis C virus (HCV) subverts host cholesterol metabolism for key processes in its lifecycle. How this interference results in the frequently observed, genotype-dependent clinical sequelae of hypocholesterolemia, hepatic steatosis, and insulin resistance (IR) remains incompletely understood. Hypocholesterolemia typically resolves after sustained viral response (SVR), implicating viral interference in host lipid metabolism. Using a targeted cholesterol metabolomic platform we evaluated paired HCV genotype 2 (G2) and G3 patient sera for changes in in vivo HCV sterol pathway metabolites. We compared HCV genotypic differences in baseline metabolites and following antiviral treatment to assess whether sterol perturbation resolved after HCV eradication. We linked these metabolites to IR and urine oxidative stress markers. In paired sera from HCV G2 (n = 13) and G3 (n = 20) patients, baseline sterol levels were lower in G3 than G2 for distal metabolites (7-dehyrocholesterol (7DHC) 0.017 versus 0.023 mg/dL; P(adj) = 0.0524, cholesterol 140.9 versus 178.7 mg/dL; P(adj) = 0.0242) but not the proximal metabolite lanosterol. In HCV G3, SVR resulted in increased levels of distal metabolites (cholesterol [Δ55.2 mg/dL; P(adj) = 0.0015], 7DHC [Δ0.0075 mg/dL; P(adj) = 0.0026], lathosterol [Δ0.0430 mg/dL P(adj) = 0.0405]). In contrast, lanosterol was unchanged after SVR (P = 0.9515). CONCLUSION: HCV G3, but not G2, selectively interferes with the late cholesterol synthesis pathway, evidenced by lower distal sterol metabolites and preserved lanosterol levels. This distal interference resolves with SVR. Normal lanosterol levels provide a signal for the continued proteolysis of 3-hydroxyl-3-methylglutaryl coenzyme A reductase, which may undermine other host responses to increase cholesterol synthesis. These data may provide a hypothesis to explain why hypocholesterolemia persists in chronic HCV infection, particularly in HCV G3, and is not overcome by host cholesterol compensatory mechanisms.

Cholesterol metabolism is required for intracellular hedgehog signal transduction in vivo.

We describe the rudolph mouse, a mutant with striking defects in both central nervous system and skeletal development. Rudolph is an allele of the cholesterol biosynthetic enzyme, hydroxysteroid (17-beta) dehydrogenase 7, which is an intriguing finding given the recent implication of oxysterols in mediating intracellular Hedgehog (Hh) signaling. We see an abnormal sterol profile and decreased Hh target gene induction in the rudolph mutant, both in vivo and in vitro. Reduced Hh signaling has been proposed to contribute to the phenotypes of congenital diseases of cholesterol metabolism. Recent in vitro and pharmacological data also indicate a requirement for intracellular cholesterol synthesis for proper regulation of Hh activity via Smoothened. The data presented here are the first in vivo genetic evidence supporting both of these hypotheses, revealing a role for embryonic cholesterol metabolism in both CNS development and normal Hh signaling.

Desmosterolosis-phenotypic and molecular characterization of a third case and review of the literature.

Desmosterolosis, a rare disorder of cholesterol biosynthesis, is caused by mutations in DHCR24, the gene encoding the enzyme 24-dehydrocholesterol reductase (DHCR24). To date, desmosterolosis has been described in only two patients. Here we report on a third patient with desmosterolosis who presented after delivery with relative macrocephaly, mild arthrogryposis, and dysmorphic facial features. Brain MRI revealed hydrocephalus, thickening of the tectum and massa intermedia, mildly effaced gyral pattern, underopercularization, and a thin corpus callosum. The diagnosis of desmosterolosis was established by detection of significant elevation of plasma desmosterol levels and reduced enzyme activity of DHCR24 upon expression of the patient's DHCR24 cDNA in yeast. The patient was found to be a compound heterozygote for c.281G>A (p.R94H) and c.1438G>A (p.E480K) mutations. Structural and evolutionary analyses showed that residue R94 resides at the flavin adenine dinucleotide (FAD) binding site and is strictly conserved throughout evolution, while residue E480 is less conserved, but the charge shift substitution is accompanied by drastic changes in the local protein environment of that residue. We compare the phenotype of our patient with previously reported cases.

Mutations in the human SC4MOL gene encoding a methyl sterol oxidase cause psoriasiform dermatitis, microcephaly, and developmental delay.

Defects in cholesterol synthesis result in a wide variety of symptoms, from neonatal lethality to the relatively mild dysmorphic features and developmental delay found in individuals with Smith-Lemli-Opitz syndrome. We report here the identification of mutations in sterol-C4-methyl oxidase­like gene (SC4MOL) as the cause of an autosomal recessive syndrome in a human patient with psoriasiform dermatitis, arthralgias, congenital cataracts, microcephaly, and developmental delay. This gene encodes a sterol-C4-methyl oxidase (SMO), which catalyzes demethylation of C4-methylsterols in the cholesterol synthesis pathway. C4-Methylsterols are meiosis-activating sterols (MASs). They exist at high concentrations in the testis and ovary and play roles in meiosis activation. In this study, we found that an accumulation of MASs in the patient led to cell overproliferation in both skin and blood. SMO deficiency also substantially altered immunocyte phenotype and in vitro function. MASs serve as ligands for liver X receptors α and ß(LXRα and LXRß), which are important in regulating not only lipid transport in the epidermis, but also innate and adaptive immunity. Deficiency of SMO represents a biochemical defect in the cholesterol synthesis pathway, the clinical spectrum of which remains to be defined.

Hypomorphic temperature-sensitive alleles of NSDHL cause CK syndrome.

CK syndrome (CKS) is an X-linked recessive intellectual disability syndrome characterized by dysmorphism, cortical brain malformations, and an asthenic build. Through an X chromosome single-nucleotide variant scan in the first reported family, we identified linkage to a 5 Mb region on Xq28. Sequencing of this region detected a segregating 3 bp deletion (c.696_698del [p.Lys232del]) in exon 7 of NAD(P) dependent steroid dehydrogenase-like (NSDHL), a gene that encodes an enzyme in the cholesterol biosynthesis pathway. We also found that males with intellectual disability in another reported family with an NSDHL mutation (c.1098 dup [p.Arg367SerfsX33]) have CKS. These two mutations, which alter protein folding, show temperature-sensitive protein stability and complementation in Erg26-deficient yeast. As described for the allelic disorder CHILD syndrome, cells and cerebrospinal fluid from CKS patients have increased methyl sterol levels. We hypothesize that methyl sterol accumulation, not only cholesterol deficiency, causes CKS, given that cerebrospinal fluid cholesterol, plasma cholesterol, and plasma 24S-hydroxycholesterol levels are normal in males with CKS. In summary, CKS expands the spectrum of cholesterol-related disorders and insight into the role of cholesterol in human development.

A model of Costeff Syndrome reveals metabolic and protective functions of mitochondrial OPA3.

Costeff Syndrome, which is caused by mutations in the OPTIC ATROPHY 3 (OPA3) gene, is an early-onset syndrome characterized by urinary excretion of 3-methylglutaconic acid (MGC), optic atrophy and movement disorders, including ataxia and extrapyramidal dysfunction. The OPA3 protein is enriched in the inner mitochondrial membrane and has mitochondrial targeting signals, but a requirement for mitochondrial localization has not been demonstrated. We find zebrafish opa3 mRNA to be expressed in the optic nerve and retinal layers, the counterparts of which in humans have high mitochondrial activity. Transcripts of zebrafish opa3 are also expressed in the embryonic brain, inner ear, heart, liver, intestine and swim bladder. We isolated a zebrafish opa3 null allele for which homozygous mutants display increased MGC levels, optic nerve deficits, ataxia and an extrapyramidal movement disorder. This correspondence of metabolic, ophthalmologic and movement abnormalities between humans and zebrafish demonstrates a phylogenetic conservation of OPA3 function. We also find that delivery of exogenous Opa3 can reduce increased MGC levels in opa3 mutants, and this reduction requires the mitochondrial localization signals of Opa3. By manipulating MGC precursor availability, we infer that elevated MGC in opa3 mutants derives from extra-mitochondrial HMG-CoA through a non-canonical pathway. The opa3 mutants have normal mitochondrial oxidative phosphorylation profiles, but are nonetheless sensitive to inhibitors of the electron transport chain, which supports clinical recommendations that individuals with Costeff Syndrome avoid mitochondria-damaging agents. In summary, this paper introduces a faithful Costeff Syndrome model and demonstrates a requirement for mitochondrial OPA3 to limit HMG-CoA-derived MGC and protect the electron transport chain against inhibitory compounds.

Cyclopia (synophthalmia) in Smith-Lemli-Opitz syndrome: First reported case and consideration of mechanism.

Here we present a 24-week fetus with Smith-Lemli-Opitz syndrome (SLOS), alobar holoprosencephaly (HPE) and cyclopia (synophthalmia). Following birth, we suspected SLOS in this fetus due to the additional findings of ambiguous genitalia and bilateral 2-3 toe syndactyly. The diagnosis of SLOS was confirmed by finding an elevated amniotic fluid 7-dehydrocholesterol level (9,890 ng/ml; normal range = 3-9 ng/ml), and molecularly by detecting two different mutations in the DHCR7 gene, the gene causing SLOS. The first mutation was an IVS8-1G>T change and the second was a deletion of exons 3 and 4; this latter mutation has not been reported previously. The mother carries the deletion, while the father carries the splice-site mutation. Also of note, the father has an abnormally low total plasma cholesterol level (104-109 mg/dl). This is the most severe case of HPE described in any patient with SLOS. We postulate that the HPE in this case resulted from severe impairment of Sonic Hedgehog signaling secondary to abnormal cholesterol metabolism; however, the unique combination of mutations in the fetus functionally appears to be no different from other homozygous null mutations reported in DHCR7. Therefore, there must be other yet to be identified factors that contributed to the severity of HPE in SLOS.

Mitochondrial disease in autism spectrum disorder patients: a cohort analysis.

BACKGROUND: Previous reports indicate an association between autism spectrum disorders (ASD) and disorders of mitochondrial oxidative phosphorylation. One study suggested that children with both diagnoses are clinically indistinguishable from children with idiopathic autism. There are, however, no detailed analyses of the clinical and laboratory findings in a large cohort of these children. Therefore, we undertook a comprehensive review of patients with ASD and a mitochondrial disorder. METHODOLOGY/PRINCIPAL FINDINGS: We reviewed medical records of 25 patients with a primary diagnosis of ASD by DSM-IV-TR criteria, later determined to have enzyme- or mutation-defined mitochondrial electron transport chain (ETC) dysfunction. Twenty-four of 25 patients had one or more major clinical abnormalities uncommon in idiopathic autism. Twenty-one patients had histories of significant non-neurological medical problems. Nineteen patients exhibited constitutional symptoms, especially excessive fatigability. Fifteen patients had abnormal neurological findings. Unusual developmental phenotypes included marked delay in early gross motor milestones (32%) and unusual patterns of regression (40%). Levels of blood lactate, plasma alanine, and serum ALT and/or AST were increased at least once in 76%, 36%, and 52% of patients, respectively. The most common ETC disorders were deficiencies of complex I (64%) and complex III (20%). Two patients had rare mtDNA mutations of likely pathogenicity. CONCLUSIONS/SIGNIFICANCE: Although all patients' initial diagnosis was idiopathic autism, careful clinical and biochemical assessment identified clinical findings that differentiated them from children with idiopathic autism. These and prior data suggest a disturbance of mitochondrial energy production as an underlying pathophysiological mechanism in a subset of individuals with autism.

Dehydrosteroid measurements in maternal urine or serum for the prenatal diagnosis of Smith-Lemli-Opitz syndrome (SLOS).

In a large multi-center trial involving prenatal screening for Smith-Lemli-Opitz syndrome (SLOS), we evaluated maternal urine and serum steroid analysis as a non-invasive diagnostic alternative to amniotic fluid sterol analysis. Candidate steroid ratios included: 7-dehydropregnanetriol/pregnanetriol (7-PT/PT), 8-dehydropregnanetriol/PT (8-PT/PT), the sum of these two (7 + 8-PT/PT), and dehydroestriol/estriol (DHE3/E3). Results are presented from 19 SLOS pregnancies, and 732 reference pregnancies that were screen positive for SLOS but negative on testing in amniotic fluid. Steroid ratios are expressed as multiples of the 75th centile (MoS), rather than multiples of the median, as most reference measurements were undetectable. All four urine ratios were available in 12 SLOS pregnancies; the median 7-PT/PT MoS was 94, with no overlap between affected and reference pregnancies in the second trimester. The separation between these groups increased by 27% per week. The other three ratios performed similarly in urine, with (7 + 8)-PT/PT ratios being marginally superior, due to fewer high reference outliers. All four steroid ratios in urine were diagnostic for SLOS between 14 and 22 weeks' gestation. In six SLOS pregnancies in which all serum analytes were measured, the median 7-PT/PT MoS was 71, and there was slight overlap in the second trimester. The separation increased by 28% per week. Steroid ratios in serum were less definitive than in urine but might be useful in certain circumstances, at 14 weeks gestation or later. Urine testing performance prior to 14 weeks gestation appears promising, but reference data are sparse.