Reductase Deficiency Research Articles

Association study of CYP17 and HSD11B1 in polycystic ovary syndrome utilizing comprehensive gene coverage

Cytochrome P450-C17 enzyme (CYP17) is an important component of the androgen synthesis pathway, a pathway that is dysfunctional in polycystic ovary syndrome (PCOS). Variation in 11-beta hydroxysteroid dehydrogenase (HSD11B1) is associated with cortisone reductase deficiency, a condition with a phenotype similar to PCOS. Both CYP17 and HSD11B1 genes have been previously studied for their possible relationship with PCOS, yielding inconsistent results. In this study, we evaluated the association between variation in these genes and PCOS. Two-hundred and eighty-seven Caucasian PCOS women and 187 Caucasian controls were genotyped for single nucleotide polymorphisms (SNPs) that were specifically chosen to allow full coverage of CYP17 and HSD11B1, including four SNPs in CYP17 and eight SNPs in HSD11B1. SNP and haplotype association analyses were conducted. Our results indicate that variants in the two genes are not associated with PCOS, or with the quantitative traits characteristic of PCOS, suggesting that these genes are not major risk factors for the syndrome.

A Physico-Biochemical Study on Potential Redox-Cyclers as Antimalarial and Antischistosomal Drugs

The role of redox enzymes in establishing a microenvironment for parasite development is well characterized. Mimicking human glucose-6-phosphate dehydrogenase and glutathione reductase (GR) deficiencies by redox-cycling compounds thus represents a challenge to the design of new preclinical antiparasitic drug candidates. Schistosomes and malarial parasites feed on hemoglobin. Heme, the toxic prosthetic group of the protein, is not digested and represents a challenge to the redox metabolism of the parasites. Here, we report on old and new redox-cycling compounds--whose antiparasitic activities are related to their interference with (met)hemoglobin degradation and hematin crystallization. Three key-assays allowed probing and differentiating the mechanisms of drug actions. Inhibition of β-hematin was first compared to the heme binding as a possible mode of action. All tested ligands interact with the hematin π-π dimer with K(D) similar to those measured for the major antiparasitic drugs. No correlation between a high affinity for hematin and the capacity to prevent β-hematin formation was however deduced. Inhibition of β-hematin formation is consequently not the result of a single process but results from redox processes following electron transfers from the drugs to iron(III)-containing targets. The third experiment highlighted that several redox-active compounds (in their reduced forms) are able to efficiently reduce methemoglobin to hemoglobin in a GR/NADPH-coupled assay. A correlation between methemoglobin reduction and inhibition of β-hematin was shown, demonstrating that both processes are closely related. The ability of our redox-cyclers to trigger methemoglobin reduction therefore constitutes a critical step to understand the mechanism of action of our drug candidates.

Life with too much polyprenol: polyprenol reductase deficiency

Congenital disorders of glycosylation (CDG) are caused by a dysfunction of glycosylation, an essential step in the manufacturing process of glycoproteins. This paper focuses on a 6-year-old patient with a new type of CDG-I caused by a defect of the steroid 5α reductase type 3 gene (SRD5A3). The clinical features were psychomotor retardation, pathological nystagmus, slight muscular hypotonia and microcephaly. SRD5A3 was recently identified encoding the polyprenol reductase, an enzyme catalyzing the final step of the biosynthesis of dolichol, which is required for the assembly of the glycans needed for N-glycosylation.Although an early homozygous stop-codon (c.57G>A [W19X]) with no functional protein was found in the patient, about 70% of transferrin (Tf) was correctly glycosylated. Quantification of dolichol and unreduced polyprenol in the patient's fibroblasts demonstrated a high polyprenol/dolichol ratio with normal amounts of dolichol, indicating that high polyprenol levels might compete with dolichol for the initiation of N-glycan assembly but without supporting normal glycosylation and that there must be an alternative pathway for dolichol biosynthesis.

Phenotypic spectrum of fetal Smith–Lemli–Opitz syndrome

The Smith–Lemli–Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation syndrome caused by dehydrocholesterol reductase deficiency. The diagnosis is confirmed by high 7- and secondarily 8-dehydrocholesterol levels in plasma and tissues and/or by detection of biallelic mutations in the DHCR7 gene. The phenotypic spectrum of SLOS is broad, ranging from a mild phenotype combining subtle physical anomalies with behavioral and learning problems, to a perinatally lethal multiple malformations syndrome. The fetal phenotype of SLOS has been poorly described in the literature. We report a series of 10 fetuses with molecularly proven SLOS. Even in young fetuses, the facial dysmorphism appears characteristic. Genital abnormalities are rare in 46,XX subjects. Gonadal differentiation appears histologically normal and in agreement with the chromosomal sex, contrary to what has been previously stated. We observed some previously unreported anomalies: ulnar hypoplasia, vertebral segmentation anomalies, congenital pulmonary adenomatoid malformation, fused lungs, gastroschisis, holomyelia and hypothalamic hamartoma. This latter malformation proves that SLOS phenotypically overlaps with Pallister-Hall syndrome which remains clinically a major differential diagnosis of SLOS.

Understanding pyrroline‐5‐carboxylate synthetase deficiency: clinical, molecular, functional, and expression studies, structure‐based analysis, and novel therapy with arginine

Δ(1)-Pyrroline-5-carboxylate synthetase (P5CS) catalyzes the first two steps of ornithine/proline biosynthesis. P5CS deficiency has been reported in three families, with patients presenting with cutis/joint laxity, cataracts, and neurodevelopmental delay. Only one family exhibited metabolic changes consistent with P5CS deficiency (low proline/ornithine/citrulline/arginine; fasting hyperammonemia). Here we report a new P5CS-deficient patient presenting the complete clinical/metabolic phenotype and carrying p.G93R and p.T299I substitutions in the γ-glutamyl kinase (γGK) component of P5CS. The effects of these substitutions are (1) tested in mutagenesis/functional studies with E.coli γGK, (2) rationalized by structural modelling, and (3) reflected in decreased P5CS protein in patient fibroblasts (shown by immunofluorescence). Using optical/electron microscopy on skin biopsy, we show collagen/elastin fiber alterations that may contribute to connective tissue laxity and are compatible with our angio-MRI finding of kinky brain vessels in the patient. MR spectroscopy revealed decreased brain creatine, which normalized after sustained arginine supplementation, with improvement of neurodevelopmental and metabolic parameters, suggesting a pathogenic role of brain creatine decrease and the value of arginine therapy. Morphological and functional studies of fibroblast mitochondria show that P5CS deficiency is not associated with the mitochondrial alterations observed in Δ(1)-pyrroline-5-carboxylate reductase deficiency (another proline biosynthesis defect presenting cutis laxa and neurological alterations).

Aldose reductase deficiency in mice protects from ragweed pollen extract (RWE)-induced allergic asthma

BackgroundChildhood hospitalization related to asthma remains at historically high levels, and its incidence is on the rise world-wide. Previously, we have demonstrated that aldose reductase (AR), a regulatory enzyme of polyol pathway, is a major mediator of allergen-induced asthma pathogenesis in mouse models. Here, using AR null (AR-/-) mice we have investigated the effect of AR deficiency on the pathogenesis of ragweed pollen extract (RWE)-induced allergic asthma in mice and also examined the efficacy of enteral administration of highly specific AR inhibitor, fidarestat.MethodsThe wild type (WT) and AR-/- mice were sensitized and challenged with RWE to induce allergic asthma. AR inhibitor, fidarestat was administered orally. Airway hyper-responsiveness was measured in unrestrained animals using whole body plethysmography. Mucin levels and Th2 cytokine in broncho-alveolar lavage (BAL) were determined using mouse anti-Muc5A/C ELISA kit and multiplex cytokine array, respectively. Eosinophils infiltration and goblet cells were assessed by H&E and periodic acid Schiff (PAS)-staining of formalin-fixed, paraffin-embedded lung sections. T regulatory cells were assessed in spleen derived CD4+CD25+ T cells population.ResultsDeficiency of AR in mice led to significantly decreased PENH, a marker of airway hyper-responsiveness, metaplasia of airway epithelial cells and mucus hyper-secretion following RWE-challenge. This was accompanied by a dramatic decrease in infiltration of eosinophils into sub-epithelium of lung as well as in BAL and release of Th2 cytokines in response to RWE-challenge of AR-/- mice. Further, enteral administration of fidarestat significantly prevented eosinophils infiltration, airway hyper-responsiveness and also markedly increased population of T regulatory (CD4+CD25+FoxP3+) cells as compared to RWE-sensitized and challenged mice not treated with fidarestat.ConclusionOur results using AR-/- mice strongly suggest the role of AR in allergic asthma pathogenesis and effectiveness of oral administration of AR inhibitor in RWE-induced asthma in mice supports the use of AR inhibitors in the treatment of allergic asthma.

Update and new concepts in vitamin responsive disorders of folate transport and metabolism

Derivatives of folic acid are involved in transfer of one-carbon units in cellular metabolism, playing a role in synthesis of purines and thymidylate and in the remethylation of homocysteine to form methionine. Five inborn errors affecting folate transport and metabolism have been well studied: hereditary folate malabsorption, caused by mutations in the gene encoding the proton-coupled folate transporter (SLC46A1); glutamate formiminotransferase deficiency, caused by mutations in the FTCD gene; methylenetetrahydrofolate reductase deficiency, caused by mutations in the MTHFR gene; and functional methionine synthase deficiency, either as the result of mutations affecting methionine synthase itself (cblG, caused by mutations in the MTR gene) or affecting the accessory protein methionine synthase reductase (cblE, caused by mutations in the MTRR gene). Recently additional inborn errors have been identified. Cerebral folate deficiency is a clinically heterogeneous disorder, which in a few families is caused by mutations in the FOLR1 gene. Dihydrofolate reductase deficiency is characterized by megaloblastic anemia and cerebral folate deficiency, with variable neurological findings. It is caused by mutations in the DHFR gene. Deficiency in the trifunctional enzyme containing methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase and formyltetrahydrofolate synthetase activities, has been identified in a single patient with megaloblastic anemia, atypical hemolytic uremic syndrome and severe combined immune deficiency. It is caused by mutations in the MTHFD1 gene.

Molecular Characterization of Hemoglobinopathies and Red Cell Enzymopathies in the Czech and Slovak Populations: An Update

Abstract 5307 Background:Thalassemias are rare disorders in Middle Europe. However, as a result of historical and recent migration, thalassemias became common cause of congenital anemia in the Czech and Slovak populations. Abnormal hemoglobin variants and red-cell enzymopathies are rare cause of congenital anemia in this region.The aim of this work was to update the original reports of this research published almost two decades ago (Indrak et al., Hum Genet 1992; 88:399–404, Xu et al., Blood 1995; 85:257–63, Lenzner et al., Blood 1997; 89:1793–9). We assessed the frequency and spectrum of β-globin gene mutations in the patients with clinical symptoms of β-thalassemia or δ,β-thalassemia, the α-globin gene status in the patients with clinical symptoms of α-thalassemia, and we characterized red cell enzymopathies on molecular level in the Czech and Slovak populations. Patients and methods:Nearly 390 cases with clinical symptoms of thalassemia or hereditary nonspherocytic hemolytic anemia from several centers of Czech and Slovak Republic were analyzed. Hematological parameters, hemoglobin electrophoresis and enzyme activities were measured by standard procedures. Genomic DNA was used for PCR-sequencing analysis. Results:We identified 22 β-thalassemia mutations in more than 260 heterozygotes; most of the mutations were of Mediterranean origin. The newly discovered insertion of transposable element L1 into the HBB gene represents a novel etiology of β-thalassemia due to a silencing effect of repressive chromatin associated with retrotransposon insertion. The list of abnormal hemoglobins now contains 14 β-globin variants, involving Heinz body hemolytic anemia variant Hb Hana (β63(E7) His-Asn), phenotype of which was worsened by concomitant partial glutathione reductase deficiency (Mojzikova et al., Blood Cells Mol Dis 2010; 45:219–22).Several G6PD and PK variants were described in the Czech and Slovak populations; the G6PD variants include G6PD Olomouc, G6PD Varnsdorf and G6PD Praha. Recently, we identified a new frameshift mutation c. 1553delG (p. Arg518fs) at the homozygous state in exon 11 of the PKLR gene of the pediatric patient who suffered from transfusion dependent hemolytic anemia with Hb=9.4 g/dL, Ret=4.5%. His red cells PK activity was 4.52 IU/gHb (normal range 13–17 IU/gHb). The mutation occurs in C domain of PK-R subunit containing the binding site for fructose-1,6-bisphosphate. The patient’s extremely elevated level of growth differentiation factor 15 (GDF15, 3577 pg/mL, healthy controls 231–345 pg/mL) could explain hereditary hemochromatosis and signs of iron overload in this patient. Conclusions:In the Czech and Slovak populations, hemoglobinopathies and red-cell enzymopathies appear to be an uncommon disorder, which, however, must be considered as the prevailing cause of congenital anemia. Most of the thalassemia patients were heterozygous, manifesting thalassemia minor. Most of the hemoglobin variants were described in single families, some of them originated locally. Among hemolytic anemias due to red-cell enzymopathies is the most frequent PK deficiency.This work was supported by grants NT11208, NS10281 (Ministry of Health Czech Republic), MSM6198959205 (Ministry of Education, Youth and Sports) and student projects LF_2011_006 and LF_2011_011 of the Palacky University. Disclosures:No relevant conflicts of interest to declare.

Management of Large Intentional Overdose of Enoxaparin with Protamine Sulfate

Abstract 4330 Introduction:Enoxaparin, a low molecular weight heparin (LMWH), is used for prophylaxis and treatment of venous and arterial thromboembolism. Due to its safety profile, there has been little literature regarding management and treatment of overdoses. Two reports of enoxaparin overdose have been described in the literature; a neonate received a 10-fold overdose and a 64-year old man received an extra daily dose. Both cases were treated with an approximate 1 to 1 ratio of protamine sulfate to LMWH (30 mg and 20 mg, respectively) and showed incomplete reversal of anticoagulation. Plasma levels of LMWH can be monitored by measuring anti-factor Xa levels; however, studies correlating large overdoses have not been performed. Peak plasma levels of LMWH are found 3–4 hours after administration, and the half-life of the drug is 4.5–7 hours. Anti-factor Xa levels, however, are not readily available at most institutions. We report a challenging case of a large overdose of LMWH, successfully treated despite the lack of appropriate laboratory monitoring tests. Case Report:A 50-year old Caucasian man with a past medical history significant for bipolar disorder, schizophrenia, hypertension, and pulmonary embolism secondary to a hypercoagulable state caused by tetrahydrofolate reductase deficiency was found unresponsive and transported to the emergency department. Upon admission, he reported self-administration of 20 subcutaneous injections of 100 mg of enoxaparin (2000 mg) and 8 tablets of quetiapine (400 mg/tablet) in an attempt to commit suicide. He was somnolent but arousable with bruising noted around multiple injection sites on his abdomen. The remainder of his physical exam was unremarkable, and he exhibited no overt signs of bleeding. Initial laboratory assessment, approximately 2 hours post-suicide attempt, revealed an elevated aPTT of >150 seconds (reference range 23–38 seconds). Anti- factor Xa levels were not available at the time of treatment. An initial dose of protamine sulfate, 250 mg mixed in 500 ml of 0.9% sodium chloride, was infused over 3–4 hours. Repeat aPTT was 61 seconds. A second infusion of protamine sulfate was administered 2 hours later, and the aPTT decreased further to 49 seconds. Rebound phenomenon was noted 3–8.5 hours later as the aPTT increased (70 to 89 seconds), however, no additional protamine sulfate was given. At 24 hours, the aPTT was 46 seconds. The patient did not exhibit any signs of bleeding during treatment, and tolerated the infusions of protamine sulfate without any adverse effects. Subsequent testing for anti-factor Xa revealed an initial level of 4.72 IU/mL upon admit (therapeutic range 0.50 – 1.10 IU/mL), decreasing to 4.52 and 3.82 IU/mL after the infusions of protamine sulfate. The anti-factor Xa level at 24 hours was 1.39 IU/mL. Conclusion:The reversal of an enoxaparin overdose is challenging and frequently difficult to manage. Reversal with protamine sulfate is often incomplete, and infusion of the recommended dosage of 1 mg for each 1 mg of enoxaparin can be risky in large dosages. Ideally, Factor Xa levels, when available, can assist in management decision, however in emergency situations as described here, the aPTT and clinical symptoms must be used to guide treatment. Disclosures:No relevant conflicts of interest to declare.

A homozygous frameshift mutation of sepiapterin reductase gene causing parkinsonism with onset in childhood

We report two siblings that presented hypotonia and very early-onset parkinsonism. Homozygosity mapping using SNP genome scan data identified a candidate locus that was 12.2 Mega base pairs. By exome sequencing, we found a homozygous five-nucleotide deletion (c.448_452delAGAAC) in gene Sepiapterin Reductase (SPR). The mutation is predicted to lead to premature translational termination. Sepiapterin reductase deficiency (SRD) is a recently recognized dopa-responsive dystonia. Our findings show that SRD can manifest as early-onset parkinsonism, widening the spectrum of the disease phenotype and adding to the genetic heterogeneity of the disease.

Aldose reductase deficiency protects from autoimmune- and endotoxin-induced uveitis in mice.

To investigate the effect of aldose reductase (AR) deficiency in protecting the chronic experimental autoimmune (EAU) and acute endotoxin-induced uveitis (EIU) in c57BL/6 mice. The WT and AR-null (ARKO) mice were immunized with human interphotoreceptor retinoid-binding peptide (hIRPB-1-20), to induce EAU, or were injected subcutaneously with lipopolysaccharide (LPS; 100 μg) to induce EIU. The mice were killed on day 21 for EAU and at 24 hours for EIU, when the disease was at its peak, and the eyes were immediately enucleated for histologic and biochemical studies. Spleen-derived T-lymphocytes were used to study the antigen-specific immune response in vitro and in vivo. In WT-EAU mice, severe damage to the retinal wall, especially to the photoreceptor layer was observed, corresponding to a pathologic score of ∼2, which was significantly prevented in the ARKO or AR inhibitor-treated mice. The levels of cytokines and chemokines increased markedly in the whole-eye homogenates of WT-EAU mice, but not in ARKO-EAU mice. Further, expression of inflammatory marker proteins such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, and vascular cell adhesion molecule (VCAM)-1 was increased in the WT-EIU mouse eyes but not in the ARKO-EIU eyes. The T cells proliferated vigorously when exposed to the hIRPB antigen in vitro and secreted various cytokines and chemokines, which were significantly inhibited in the T cells isolated from the ARKO mice. These findings suggest that AR-deficiency/inhibition protects against acute as well as chronic forms of ocular inflammatory complications such as uveitis.

Role of a Disordered Steroid Metabolome in the Elucidation of Sterol and Steroid Biosynthesis

In 1937 Butler and Marrian found large amounts of the steroid pregnanetriol in urine from a patient with the adrenogenital syndrome, a virilizing condition known to be caused by compromised adrenal secretion even in this pre-cortisol era. This introduced the concept of the study of altered excretion of metabolites as an in vivo tool for understanding sterol and steroid biosynthesis. This approach is still viable and has experienced renewed significance as the field of metabolomics. From the first cyclized sterol lanosterol to the most downstream product estradiol, there are probably greater than 30 steps. Based on a distinctive metabolome clinical disorders have now been attributed to about seven post-squalene cholesterol (C) biosynthetic steps and around 15 en-route to steroid hormones or needed for further metabolism of such hormones. Forty years ago it was widely perceived that the principal steroid biosynthetic defects were known but interest rekindled as novel metabolomes were documented. In his career this investigator has been involved in the study of many steroid disorders, the two most recent being P450 oxidoreductase deficiency and apparent cortisone reductase deficiency. These are of interest as they are due not to mutations in the primary catalytic enzymes of steroidogenesis but in ancillary enzymes needed for co-factor oxido-reduction A third focus of this researcher is Smith-Lemli-Opitz syndrome (SLOS), a cholesterol synthesis disorder caused by 7-dehydrocholesterol reductase mutations. The late George Schroepfer, in whose honor this article has been written, contributed greatly to defining the sterol metabolome of this condition. Defining the cause of clinically severe disorders can lead to improved treatment options. We are now involved in murine gene therapy studies for SLOS which, if successful could in the future offer an alternative therapy for this severe condition.

REMOVAL: Pelvic MRI in a 17-year-old XY girl with 5-alpha reductase deficiency and a homozygous Gly115Asp mutation in SRD5A2

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been removed at the request of the Editor-in-chief and the corresponding author for legal reasons regarding the patient consent.

‘Idiopathic’ partial androgen insensitivity syndrome in 28 newborn and infant males: impact of prenatal exposure to environmental endocrine disruptor chemicals?

46,XY disorders of sex differentiation (46,XY DSD) can be due to a testis determination defect, an androgen biosynthesis defect, or androgen resistance (complete or partial androgen insensitivity syndrome (PAIS), or 5α reductase deficiency). We aimed to evaluate the impact of a prenatal contamination by environmental xenoestrogens in 'idiopathic' PAIS-like phenotype. We investigated 28 newborn/infant males with 46,XY DSD, normal androgen production, and no androgen receptor or steroid-5αR type II enzyme (SRD5A2) gene mutations. To exclude other genetic defects, we sequenced the steroidogenic factor 1 (SF1) and mastermind-like domain-containing 1 (MAMLD1) genes, which were recently found to be associated with the PAIS-like phenotype. Parents were interviewed about their environmental/occupational exposure to endocrine disrupting chemicals (EDCs) before/during the patients' fetal life. Total estrogenic bioactivity of patient serum was analyzed by ultrasensitive bioassay. All the patients had normal SF1 sequence and one patient showed a double polymorphism of MAMLD1. Eleven (39.3%) of the 28 patients had reported parental fetal exposure to EDCs. The mean estrogenic bioactivity in these 11 patients with fetal EDC exposure (6.65 ± 8.07 pg/ml) versus 17 cases without contamination (1.27 ± 0.34 pg/ml) and controls (1.06 ± 0.44 pg/ml; P<0.05) was elevated. Our results indicate that the 'idiopathic' PAIS-like phenotype may in some cases be related to EDC contamination during fetal life.

Hemolytic uremic syndrome and rhabdomyolysis in a patient with succinate coenzyme Q reductase (complex II) deficiency

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. Besides diarrhea-associated HUS, due to verotoxin-producing Escherichia coli, in children HUS without prodromal diarrhea may be associated with other infectious and autoimmune diseases, genetic defects of the complement-regulator alternative-pathway, and inborn errors of vitamin B12 metabolism. Rhabdomyolysis is the dissolution of skeletal muscle due to various causes, including inborn errors of metabolism. Recurrent rhabdomyolysis and HUS have been previously described in one patient with a genetic defect of oxidative phosphorylation. We report the case of a 2-year-old boy with recurrent HUS and rhabdomyolysis in whom a succinate coenzyme Q reductase (complex II) deficiency was diagnosed. We hypothesize that defects of oxidative phosphorylation could be another etiological factor in atypical HUS.

Premature adrenarche: novel lessons from early onset androgen excess

Adrenarche reflects the maturation of the adrenal zona reticularis resulting in increased secretion of the adrenal androgen precursor DHEA and its sulphate ester DHEAS. Premature adrenarche (PA) is defined by increased levels of DHEA and DHEAS before the age of 8 years in girls and 9 years in boys and the concurrent presence of signs of androgen action including adult-type body odour, oily skin and hair and pubic hair growth. PA is distinct from precocious puberty, which manifests with the development of secondary sexual characteristics including testicular growth and breast development. Idiopathic PA (IPA) has long been considered an extreme of normal variation, but emerging evidence links IPA to an increased risk of developing the metabolic syndrome (MS) and thus ultimately cardiovascular morbidity. Areas of controversy include the question whether IPA in girls is associated with a higher rate of progression to the polycystic ovary syndrome (PCOS) and whether low birth weight increases the risk of developing IPA. The recent discoveries of two novel monogenic causes of early onset androgen excess, apparent cortisone reductase deficiency and apparent DHEA sulphotransferase deficiency, support the notion that PA may represent a forerunner condition for PCOS. Future research including carefully designed longitudinal studies is required to address the apparent link between early onset androgen excess and the development of insulin resistance and the MS.

Cerebral Folate Deficiency Syndromes in Childhood

Cerebral folate deficiency may be amenable to therapeutic supplementation. Diverse metabolic pathways and unrelated processes can lead to cerebrospinal fluid 5-methyltetrahydrofolate (5-MTHF) depletion, the hallmark of cerebral folate deficiency. To analyze cerebral folate abundance in a large prospective series of children diagnosed with any neurologic disorder for which a diagnostic lumbar puncture was indicated. We studied the spectrum and frequency of disorders associated with cerebral folate deficiency by measuring cerebrospinal fluid 5-MTHF, biogenic amines, and pterins. Direct sequencing of the FOLR1 transporter gene was also performed in some patients. Academic pediatric medical center. We studied 134 individuals free of neurometabolic disease and 584 patients with any of several diseases of the central nervous system. Of 584 patients, 71 (12%) exhibited 5-MTHF deficiency. Mild to moderate deficiency (n=63; range, 19-63 nmol/L) was associated with perinatal asphyxia, central nervous system infection, or diseases of probable genetic origin (inborn errors of metabolism, white matter disorders, Rett syndrome, or epileptic encephalopathies). Severe 5-MTHF depletion (n=8; range, 0.6-13 nmol/L) was detected in severe MTHF reductase deficiency, Kearns-Sayre syndrome, biotin-responsive striatal necrosis, acute necrotizing encephalitis of Hurst, and FOLR1 defect. A strong correlation was observed between cerebrospinal fluid and plasma folate levels in cerebral folate deficiency. Of the 2 main forms of cerebral folate deficiency identified, mild to moderate 5-MTHF deficiency was most commonly associated with disorders bearing no primary relation to folate metabolism, whereas profound 5-MTHF depletion was associated with specific mitochondrial disorders, metabolic and transporter defects, or cerebral degenerations. The results suggest that 5-MTHF can serve either as the hallmark of inborn disorders of folate transport and metabolism or, more frequently, as an indicator of neurologic dysfunction.

Acute leukoencephalopathy possibly induced by phenytoin intoxication in an adult patient with methylenetetrahydrofolate reductase deficiency

A 19-year-old university student with no personal or family history of neurologic disorders developed convulsions and was administered phenytoin. Two months later, he developed lower limb-dominant acute demyelinating polyneuropathy, from which he recovered within 2 months. At age 20, he rapidly developed visual disturbances and paraplegia from phenytoin intoxication. Cranial magnetic resonance imaging (MRI) revealed leukoencephalopathy with no evidence of thrombosis or vasoconstriction. Hyperhomocysteinemia, hypomethioninemia, low serum folate concentration, and an absence of megaloblastic anemia were consistent with the diagnosis of methylenetetrahydrofolate reductase (MTHFR) deficiency. A genomic DNA sequence analysis demonstrated compound heterozygosity for two missense mutations in the MTHFR gene, namely, [458G>T + 459C>T] (Gly149Val) and 358G>A (Ala116Thr), both of which are known pathogenic mutations. An absence of leukoencephalopathic changes on MRI scans performed 9 months previously strongly suggested that phenytoin intoxication caused acute leukoencephalopathy. Therefore, phenytoin may be an aggravating factor of remethylation defects in patients with MTHFR deficiency.

Dihydrofolate reductase mutations-associated megaloblastic anemia and cerebral folate deficiency

Dihydrofolate reductase deficiency due to a homozygous DHFR mutation causes megaloblastic anemia and cerebral folate deficiency leading to severe neurologic disease Cario et al. (2011) American Journal of Human Genetics 88:226-231

Prevalence of hypospadias in grandsons of women exposed to diethylstilbestrol during pregnancy: a multigenerational national cohort study

Prenatal diethylstilbestrol (DES)-exposed mice have raised the suspicion of a transgenerational effect in the occurrence of genital malformation in males. This nationwide cohort study in collaboration with a French association of DES-exposed women studied 529 families and showed that a significant proportion of boys born to DES daughters exhibited hypospadias with no other molecular defects identified.