Reductase Deficiency Research Articles

PS1201 : MOLECULAR STUDY OF RED CELL NADH‐CYTOCHROME B5 REDUCTASE DEFICIENCY IN 21 INDIAN PATIENTS WITH RECESSIVE HEREDITARY METHEMOGLOBINAEMIA

Background:Recessive congenital methemoglobinemia (RCM) due to NADH–cytochrome b5 reductase 3 (cyb5r3) deficiencies is an autosomal recessive disorder that occurs sporadically worldwide. Over seventy six different mutations have been described for RCM.Aims:The aim of this study molecular basis of RCM in 21 patients and prenatal diagnosis in 4 cases with severe mental retardation and neurological disabilities along with a comprehensive review of all the pathogenic mutations in cyb5r3 and their molecular pathology in RCM.Methods:Twenty‐five cases were analyzed amongst which 21 cases were diagnosed with NADH‐CYB5R deficiency based on significantly reduced NADH‐CYB5R activity while 4 were referred for prenatal screening. The study has been approved by the National Institute of Immunohematology Ethical committee and as per protocol, written informed consents were obtained from all the patients or their parents. Complete blood counts were measured by automated hematology analyzer XN (Sysmex, Kobe, Japan). Methemoglobin estimation, G6PD, and NADH‐Cyb5R enzyme assay were performed as described by Beutler et al. method. DNA was extracted from the Blood/CVS using Qiagen DNA extraction kit according to the manufacturer's instructions. PCR exon‐specific primers were utilized and PCR and Sanger's sequencing was performed by a standard method. Molecular modeling of cyb5r3 was done using the PYMOL and SWISS‐PDB viewer tool.Results:In the 21 patients analyzed in this study, all index cases from twenty unrelated families were referred for the cause of cyanosis. All patients showed mild to moderate cyanosis and few patients had mental retardation or any neurologic abnormalities. Methemoglobin levels were increased, varying from 8.5% to 65%. NADH‐Cyb5r3 activity was seen to be in the range of 6 to 19%. In the molecular analysis, eighteen mutations (fourteen missense, one deletion, one‐stop codon, and 1 splice‐site mutation) were observed (Figure 1) in this study. Amongst fourteen missense mutations 5 were novel mutations [c.105A>C (p.Thr35Arg), c.192C>G (p.Leu64Val), c.312G>T (p.Gly104Cys), c.354C>T (p.His118Tyr) and c.470T>G (p.Phe157Cys)]. Over seventy‐six different mutations have been described for RCM globally (Figure 1). Same mutations are associated with the severe form with a neurological disorder (RCM type 2) were associated with the FAD‐binding domain of the protein while rests were located in the other domains of the protein (RCM Type 1). One of the prenatal analyses showed splice‐site mutation p.Gly76Ser at nucleotides 226 in exon 3 of the CYB5R3 gene in the homozygous state while in another one it was found in the heterozygous state. In the third case stop codon mutation p.Gln77X at nucleotide position 229 in exon 4 was seen in the heterozygous condition. In the fourth case, normal wild type genotype for the CYB5R3 gene was found.Summary/Conclusion:This study presents the results of the first molecular study of a large number of cases of NADH cytochrome b5 reductase deficiency in India Molecular modeling of all the mutations reported in CYB5R3 justifies the association of the mutations with the varying severity of the disease. Knowing the profile of mutations in families with severe neurological disorders allowed us to offer a prenatal diagnosis of RCM Type 2 for the first time in the Indian population. Thus severity and recurrence risk of type II RCM merit could be prevented by prenatal diagnosis in affected families.image

Red Blood Cell Membrane Conductance in Hereditary Haemolytic Anaemias.

Congenital haemolytic anaemias are inherited disorders caused by red blood cell membrane and cytoskeletal protein defects, deviant hemoglobin synthesis and metabolic enzyme deficiencies. In many cases, although the causing mutation might be known, the pathophysiology and the connection between the particular mutation and the symptoms of the disease are not completely understood. Thus effective treatment is lagging behind. As in many cases abnormal red blood cell cation content and cation leaks go along with the disease, by direct electrophysiological measurements of the general conductance of red blood cells, we aimed to assess if changes in the membrane conductance could be a possible cause. We recorded whole-cell currents from 29 patients with different types of congenital haemolytic anaemias: 14 with hereditary spherocytosis due to mutations in α-spectrin, β-spectrin, ankyrin and band 3 protein; 6 patients with hereditary xerocytosis due to mutations in Piezo1; 6 patients with enzymatic disorders (3 patients with glucose-6-phosphate dehydrogenase deficiency, 1 patient with pyruvate kinase deficiency, 1 patient with glutamate-cysteine ligase deficiency and 1 patient with glutathione reductase deficiency), 1 patient with β-thalassemia and 2 patients, carriers of several mutations and a complex genotype. While the patients with β-thalassemia and metabolic enzyme deficiencies showed no changes in their membrane conductance, the patients with hereditary spherocytosis and hereditary xerocytosis showed largely variable results depending on the underlying mutation.

A case of methylenetetrahydrofolate reductase deficiency enzyme deficiency carrying a novel mutation

AbstractMethylenetetrahydrofolate reductase (MTHFR) enzyme deficiency is the most common genetic cause of elevated levels of homocysteine in the plasma (hyperhomocysteinemia). We describe a 22‐year‐old male, who presented to the clinic with history of MTHFR deficiency and homocystinuria. At baseline, the patient was nonverbal, wheelchair‐bound with seizures since young age. Physical examination showed increased spasticity and weakness in bilateral lower extremities. Elevated levels of homocysteine were seen in the serum. Genetic testing revealed a single homozygous pathogenic mutation in c.1699C>T p. R587x. not previously reported for homocystinuria. Our patient carries a unique single homozygous pathogenic mutation c.1699C>T p. R587x leading to homocystinuria that hasn't been described before. More research is required to identify the pathophysiology of this mutation and role in other diseases.

Leaky splicing variant in sepiapterin reductase deficiency: Are milder cases escaping diagnosis?

Sepiapterin reductase deficiency (SRD), an extremely rare but treatable neurotransmitter disease, is an enzyme defect in the final step of tetrahydrobiopterin (BH4) synthesis.1 Unlike other forms of BH4-deficient dopa-responsive dystonia, SRD uniquely does not manifest hyperphenylalaninemia and thus slips through detection by newborn screening. Owing to its variable presenting features and need for a sensitive method of CSF analysis, diagnosis of SRD may be compromised in mild phenotypes.2

Phenotype, treatment practice and outcome in the cobalamin-dependent remethylation disorders and MTHFR deficiency: Data from the E-HOD registry.

To explore the clinical presentation, course, treatment and impact of early treatment in patients with remethylation disorders from the European Network and Registry for Homocystinurias and Methylation Defects (E-HOD) international web-based registry. This review comprises 238 patients (cobalamin C defect n = 161; methylenetetrahydrofolate reductase deficiency n = 50; cobalamin G defect n = 11; cobalamin E defect n = 10; cobalamin D defect n = 5; and cobalamin J defect n = 1) from 47 centres for whom the E-HOD registry includes, as a minimum, data on medical history and enrolment visit. The duration of observation was 127 patient years. In 181 clinically diagnosed patients, the median age at presentation was 30 days (range 1 day to 42 years) and the median age at diagnosis was 3.7 months (range 3 days to 56 years). Seventy-five percent of pre-clinically diagnosed patients with cobalamin C disease became symptomatic within the first 15 days of life. Total homocysteine (tHcy), amino acids and urinary methylmalonic acid (MMA) were the most frequently assessed disease markers; confirmatory diagnostics were mainly molecular genetic studies. Remethylation disorders are multisystem diseases dominated by neurological and eye disease and failure to thrive. In this cohort, mortality, thromboembolic, psychiatric and renal disease were rarer than reported elsewhere. Early treatment correlates with lower overall morbidity but is less effective in preventing eye disease and cognitive impairment. The wide variation in treatment hampers the evaluation of particular therapeutic modalities. Treatment improves the clinical course of remethylation disorders and reduces morbidity, especially if started early, but neurocognitive and eye symptoms are less responsive. Current treatment is highly variable. This study has the inevitable limitations of a retrospective, registry-based design.

Taurine alleviates repression of betaine-homocysteine S-methyltransferase and significantly improves the efficacy of long-term betaine treatment in a mouse model of cystathionine β-synthase-deficient homocystinuria.

Classical cystathionine β-synthase-deficient homocystinuria (HCU) is a life-threatening inborn error of sulfur metabolism. Treatment for pyridoxine-nonresponsive HCU involves lowering homocysteine (Hcy) with a methionine (Met)-restricted diet and betaine supplementation. Betaine treatment efficacy diminishes significantly over time due to impairment of betaine-Hcy S-methyltransferase (BHMT) function. Little is known regarding the regulation of BHMT in HCU. Using a betaine-responsive preclinical mouse model of HCU, we observed that this condition induces a 75% repression of BHMT mRNA, protein and enzyme activity, and significant depletion of hepatic betaine levels. BHMT repression was proportional to plasma Hcy levels but was not observed in mouse models of homocystinuria due to either methylenetetrahydrofolate reductase or Met synthase deficiency. Both Met supplementation and chemically induced glutathione depletion exacerbated hepatic BHMT repression in HCU mice but not wild-type (WT) controls. Conversely, cysteine treatment normalized hepatic BHMT expression in HCU mice but had no effect in WT control animals. Taurine treatment induced BHMT expression in HCU mice by 5-fold and restored maximal lowering of Hcy levels during long-term betaine treatment with a concomitant normalization of inflammatory cytokine expression and a significantly improved coagulative phenotype. Collectively, our findings indicate that adjuvantial taurine treatment has the potential to significantly improve clinical outcomes in HCU.-Maclean, K. N., Jiang, H, Phinney, W. N., Keating, A. K., Hurt, K. J., Stabler, S. P. Taurine alleviates repression of betaine-homocysteine S-methyltransferase and significantly improves the efficacy of long-term betaine treatment in a mouse model of cystathionine β-synthase-deficient homocystinuria.

The clinical presentation of cobalamin-related disorders: From acquired deficiencies to inborn errors of absorption and intracellular pathways.

This review gives an overview of clinical characteristics, treatment and outcome of nutritional and acquired cobalamin (Cbl; synonym: vitamin B12) deficiencies, inborn errors of Cbl absorption and intracellular trafficking, as well as methylenetetrahydrofolate dehydrogenase (MTHFD1) and methylene tetrahydrofolate reductase (MTHFR) deficiencies, which impair Cbl-dependent remethylation. Acquired and inborn Cbl-related disorders and MTHFR deficiency cause multisystem, often severe disease. Failure to thrive, neurocognitive or psychiatric symptoms, eye disease, bone marrow alterations, microangiopathy and thromboembolic events are characteristic. The recently identified MTHFD1 defect additionally presents with severe immune deficiency. Deficient Cbl-dependent enzymes cause reduced methylation capacity and metabolite toxicity. Further net-effects of perturbed Cbl function or reduced Cbl supply causing oxidative stress, altered cytokine regulation or immune functions are discussed.

Clinical phenotype and gene analysis of 86 cases of 5 alpha reductase deficiency

Objective: Molecular genetics and clinical phenotypic characteristics of 5 alpha reductase deficiency were analyzed. Methods: The genetic results and clinical features classied as Prader grade of external genitalia of 86 children with SRD5A2 mutation seen from 2007 to 2017 at Department of Endocrinology of Beijing Children's Hospital were analyzed, and the mutation differences in different were compared regions according to the literatures. Results: Among the 86 children, 15 had were homozygous mutations, accounting for 17%, and 71 cases of compound heterozygous mutations accounted for 83%. Totally 172 alleles mutations in this series. The mutation was mainly located on exon 1 and exon 4, in which the mutation frequency of exon 1 was 23.8% (41/172), and the frequency of exon 4 mutation was 55.8% (96/172). A total of 19 mutation types of the SRD5A2 gene in this group were detected, of which 5 were new mutations (p.A228F, p.E57D, p.V124D, p.A117D, p.E197K); 65 patients had p.R227Q mutation, accounting for 76%, while 31 had p.Q6* mutation, accounting for 36%. Other rare types such as p.R246W, p.R103* and so on were also seen in the present study, there was no significant difference between north China and south China (P>0.05). The clinical phenotypes of p.R227Q variation varied, mainly in Prader 3-4, accounting for 82%, while (Prader 0-1) were less, accounting only 2%. The variation of p.Q6* was mainly manifested in Prader 3, accounting for 50%. p.R246Q mainly presented Prader 3. The variation of p.G203S appeared to have Prader 2 and Prader 4-5, accounting for 20% and 73% respectively. There was no significant difference in clinical phenotype corresponding to each protein type (P>0.05) . Conclusion: Among the 86 children have identified 19 SRD5A2 mutation types, p.R227Q is a hotspot mutation in Chinese. Variations at different types may have different clinical phenotypes, while the same variations may have different clinical features. There was no significance different in the variation types between the north and the south.

Sex assignment practice in disorders of sexual differentiation: survey results from paediatric endocrinologists in the Arab region.

Background Sex assignment is a major issue in disorders of sexual differentiation (DSD). Not all conditions of DSD have clear recommendations on assignment and timing of surgery. Reports about sex assignment practice and the influence of culture and religion in the Arab region are scarce. Methods A survey questionnaire was distributed to participants in a paediatric endocrinology conference. Four DSD cases were presented. Participants were asked to fill in their answers on sex assignment choice, reasons for the particular assignment, strength of own recommendation and timing of surgery based on their practice. The cases presented were severely virilised XX congenital adrenal hyperplasia (CAH), complete androgen insensitivity syndrome (CAIS), severely undervirilised 5α reductase deficiency (5α RD) and XX ovotesticular case. Results Eighty-five endocrinologists participated in the study. Eighty (97.5%) chose a female sex to assign for the XX CAH. For the CAIS, 64 (78%) chose a female sex. Seventy-one (86.5%) voted for a male sex for the XY case of 5α RD. Forty-seven (57%) and 35 (43%) chose a female and a male sex for the ovotesticular case, respectively. The majority indicated that their advice for sex assignment is based on strong recommendations for the CAH, CAIS and 5α RD patients but they were open to the parents' cultural and religious beliefs in their decision of the assignment for the ovotesticular case. Conclusions Practice in the Arab region appears to be in line with the international guidelines in the majority of DSD sex assignment and timing of surgery issues. However, culture and religious beliefs influence the practice in certain circumstances.

Three Main Causes of Homocystinuria: CBS, cblC and MTHFR Deficiency. What do they Have in Common?

Abstract Genetic homocystinurias are a group of inborn errors of metabolism that result in the massive excretion of homocysteine (Hcy) in the urine due to Hcy accumulation in the body, usually causing neurological and cardiovascular complications. The three most frequent causes are classical homocystinuria [deficiency of cystathionine beta-synthase (CBS)], methylmalonic aciduria with homocystinuria, cblC type (cblC deficiency) and severe methylenetetrahydrofolate reductase (MTHFR) deficiency. In this review, we highlight the similarities and differences among these disorders. Briefly, their joint manifestation is the accumulation of tHcy, however, the other sulfur amino acids show various and even invers profiles. Vascular disease, developmental delay and seizures are found in all homocystinurias, nevertheless, the complications of CNS differ in a wide variety of presentations and severities and are apparently less pronounced in CBS deficiency. Moreover, patients with remethylation defects typically do not present ectopia lentis and bone disturbances, tall stature and osteoporosis. Whereas hematological alterations, such as megaloblastic anemia, thrombocytopenia neutropenia and life-threatening microangiopathy, are specific findings of cblC deficiency.

Genetic study in a family with dopa-responsive dystonia revealed a novel mutation in sepiapterin reductase gene.

Dopa-responsive dystonia due to sepiapterin reductase deficiency (OMIM#612716) is caused by recessive mutations in the gene encoding sepiapterin reductase (SPR), which plays an important role in the biosynthesis of tetrahydrobiopterin (BH4). One Jordanian patient to first cousin parents is reported in this study. The parents of the proband have recognized the symptoms of their daughter at six months old with motor developmental delay. The symptoms were progressed after-then to include speech delay, seizure, ataxia, oculomotor apraxia, dysarthia and choreoathetosis. Despite of these symptoms, the clinicians in Jordan were unable to diagnose the case. In August 2018, the proband (8 years old) was presented to the department of biotechnology and genetic engineering at Philadelphia University in Jordan for the purposes of performing whole exome sequencing (WES). Analysis of WES data has revealed novel homozygous frameshift variant in the gene SPR (NM_003124.4:c.40delG,p.Ala15Profs*100). The variant is heterozygous in the parents and in the healthy male siblings. Therefore, the studied case was diagnosed with sepiapterin reductase deficiency. Because this disease is likely to be treated recommendations were given to the family immediately to start treatments trials. The case in this study illustrates the difficulties of diagnosing sepiapterin reductase deficiency based on clinical symptoms only and thus renders the possibilities of early management. Also, this study reinforces the importance of running WES to undiagnosed neurodevelopmental cases.

Newborn screening for homocystinurias: Recent recommendations versus current practice.

To assess how the current practice of newborn screening (NBS) for homocystinurias compares with published recommendations. Twenty-two of 32 NBS programmes from 18 countries screened for at least one form of homocystinuria. Centres provided pseudonymised NBS data from patients with cystathionine beta-synthase deficiency (CBSD, n = 19), methionine adenosyltransferase I/III deficiency (MATI/IIID, n = 28), combined remethylation disorder (cRMD, n = 56) and isolated remethylation disorder (iRMD), including methylenetetrahydrofolate reductase deficiency (MTHFRD) (n = 8). Markers and decision limits were converted to multiples of the median (MoM) to allow comparison between centres. NBS programmes, algorithms and decision limits varied considerably. Only nine centres used the recommended second-tier marker total homocysteine (tHcy). The median decision limits of all centres were ≥ 2.35 for high and ≤ 0.44 MoM for low methionine, ≥ 1.95 for high and ≤ 0.47 MoM for low methionine/phenylalanine, ≥ 2.54 for high propionylcarnitine and ≥ 2.78 MoM for propionylcarnitine/acetylcarnitine. These decision limits alone had a 100%, 100%, 86% and 84% sensitivity for the detection of CBSD, MATI/IIID, iRMD and cRMD, respectively, but failed to detect six individuals with cRMD. To enhance sensitivity and decrease second-tier testing costs, we further adapted these decision limits using the data of 15 000 healthy newborns. Due to the favorable outcome of early treated patients, NBS for homocystinurias is recommended. To improve NBS, decision limits should be revised considering the population median. Relevant markers should be combined; use of the postanalytical tools offered by the CLIR project (Collaborative Laboratory Integrated Reports, which considers, for example, birth weight and gestational age) is recommended. tHcy and methylmalonic acid should be implemented as second-tier markers.

Molecular genetics and phenotype/genotype correlation of 5-α reductase deficiency in a highly consanguineous population.

5-α reductase deficiency is a rare 46,XY disorder of sex development. We present detailed phenotypic and genotypic features of a cohort of 24 subjects from a highly consanguineous population of Saudi Arabia SUBJECTS AND METHODS: We studied the clinical presentation and hormonal profiles of 24 subjects diagnosed with 5-α reductase deficiency and performed genetic testing on DNA isolated from their peripheral blood using polymerase chain reaction and direct sequencing of the SRD5A2. All subjects had 46,XY karyotype and presented with atypical appearance of external genitalia ranging from clitoromegaly, micophallus with hypospadias, undescended testes to completely normally looking female genitalia. Thirteen (54%) of them had severe under virilization and were assigned female sex at birth. The other 11 subjects were raised as males. Stimulated Testosterone:Dihydrotestosterone ratio was high in all 16 subjects in whom it was measured. The genetic testing revealed 2 nonsense mutations (p.R103X and p.R227X) in 2 unrelated subjects, 3 missense mutations (p.P181L, p.A228T, p.R246Q) in 11 subjects and a splice site mutation (IVS1-2A > G) in 11 other subjects. There was significant phenotypic variability even in subjects with the same mutation and also within the same family. This is the first and largest report of the clinical and molecular genetics of 5-α reductase deficiency from the Middle East. It shows weak genotype/phenotype correlation and significant phenotypic heterogeneity. IVS1-2A > G mutation is the most common mutation and is likely to be a founder mutation in this part of the world.

Large divergence in testosterone concentrations between men and women: Frame of reference for elite athletes in sex-specific competition in sports, a narrative review.

The purpose of this narrative review was to summarize available data on testosterone levels in normal, healthy adult males and females, to provide a physiologic reference framework to evaluate testosterone levels reported in males and females with conditions that elevate androgens, such as disorders of sex development (DSD), and to determine the separation or overlap of testosterone levels between normal and affected males and females. A literature review was conducted for published papers, from peer reviewed journals, reporting testosterone levels in healthy males and females, males with 46XY DSD, and females with hyperandrogenism due to polycystic ovary syndrome (PCOS). Papers were selected that had adequate characterization of participants, and description of the methodology for measurement of serum testosterone and reporting of results. In the healthy, normal males and females, there was a clear bimodal distribution of testosterone levels, with the lower end of the male range being four- to fivefold higher than the upper end of the female range(males 8.8-30.9nmol/L, females 0.4-2.0nmol/L). Individuals with 46XY DSD, specifically those with 5-alpha reductase deficiency, type 2 and androgen insensitivity syndrome testosterone levels that were within normal male range. Females with PCOS or congenital adrenal hyperplasia were above the normal female range but still below the normal male range. Existing studies strongly support a bimodal distribution of serum testosterone levels in females compared to males. These data should be considered in the discussion of female competition eligibility in individuals with possible DSD or hyperandrogenism.

Gender identity in patients with 5-alpha reductase deficiency raised as females

5-Alpha reductase type 2 deficiency (5-ARD) is a rare disorder of sex development. The lack of 5-alpha reductase, an enzyme that converts testosterone into dihydrotestosterone, results in external genitalia that may appear female, or predominantly male, albeit undervirilized, or, more often, ambiguous. This study describes a series of patients with 5-ARD raised as female, focusing on aspects related to gender identity. Following a retrospective chart review, patients with 5-ARD were invited to return to the clinic to enable their gender identity to be assessed using an 11-item structured in-house questionnaire. The Golombok-Rust Inventory of Sexual Satisfaction was applied to patients who had initiated their sexual life. Six patients aged >15 years with 5-ARD and raised as female were included. Most patients were diagnosed late: two before and four after puberty. The mean length of the phallus was 2.8cm (0.5-5.0). Reasons for seeing a doctor included genital appearance (n=3), amenorrhea/absence of breast development (n=2), and changes in gender role attitudes (n=1). According to the gender identity assessment, 4 patients identified as female, 1 as male, and 1 as both genders. Only the patient identified as male requested gender re-assignment. Of the two patients who had initiated their sexual life, sexual satisfaction was found to be good in one and poor in the other due to vaginal discomfort during intercourse. In the present series, the majority of undervirilized patients with a diagnosis of 5-ARD raised as female were in complete conformation with being femaleand described themselves as heterosexual. The more virilized patients were those least in conformity with their female-assigned gender.

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.

Outcome of Patients With Inherited Neurotransmitter Disorders.

We report the outcome of 12 patients with inherited neurotransmitter disorders of monoamine, tetrahydrobiopterin and γ amino butyric acid metabolisms from a single Inherited Neurotransmitter Disorder Clinic including tyrosine hydroxylase (n=2), aromatic l-amino acid decarboxylase (n=1), 6-pyruvoyltetrahydropterin synthase, dihydropteridine reductase and succinic semialdehyde dehydrogenase deficiencies. Six patients (with 6-pyruvoyltetrahydropterin synthase, dihydropteridine reductase and tyrosine hydroxylase deficiencies) had normal neurodevelopmental outcome on treatment. Tetrahydrobiopterin loading test in newborns with positive newborn screening for phenylketonuria will identify patients with 6-pyruvoyltetrahydropterin synthase and dihydropteridine reductase deficiencies resulting in abnormal neurotransmitter synthesis in the central nervous system in the neonatal period to initiate disease-specific treatment to improve neurodevelopmental outcome.

Analysis of types and metabolic profiles of hyperphenylalaninemia

Objective To study the characteristics of hyperphenylalaninemia (HPA) and the differences in blood and urine metabolic index and their correlation. Methods A total of 137 patients with HPA diagnosed by the Pediatric Inherit Metabolism and Endocrine Department, Guangdong Women and Children′s Hospital, Guangzhou Medical University from January 2014 to June 2017, were enrolled.Tandem mass spectrometry (MS/MS), gas chromatography/mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) were used to analyze the concentration of blood and urine metabolites in children, and the patients were divided into different groups according to the drug load test of tetrahydrobiopterin (BH4) and dihydrobiopterindine reductase (DHPR) deficiency.The HPA metabolite analysis of horizontal concentration by statistical differences and correlation analysis were performed. Results Among the 137 cases of HPA, there were 101 cases (73.7%) of phenylalanine hydroxylase deficiency (PAH), and among them 21 cases (15.3%) were classic phenylketonuria (PKU), 37 cases were mild PKU (27.0%), 43 cases (31.4%) were mild HPA.There were 22 cases (16.1%) with BH4 reaction, and 79 cases (57.7%) of non-reactive type.Besides, there were 36 cases(26.3%) of tetrahydrobiopterin deficiency (BH4D), of which 6-pyruvoyl tetrahydropterin synthase deficiency(PTPS) in 34 cases(24.8%) and dihydrobiopterindine reductase deficiency (DHPR) in 2 cases (1.5%). Urinary phenylacetic acid (r=0.673, P 0.05). Conclusions Through the analysis of the different types of HPA metabolic profiles, it can help to master the incidence and characteristics in the region, within a certain concentration range of blood Phe, the phenylacetic acid, phenyllactic acid, phenylpyruvic acid should not be tested by GC-MS alone.Uterine erythropoietin analysis of BH4D classification and identification of BH4 reaction, non-reactive PKU have a supporting role, so master the metabolic index of various types of concentration and relevance of HPA, it can provide basis for early diagnosis, accurate treatment and follow-up. Key words: Hyperphenylalaninemia; Metabolic profiling; Phenylalanine hydroxylase deficiency; Tetrahydrobiopterin deficiency

The Acute Treatment of Methemoglobinemia in Pregnancy

BackgroundMethemoglobinemia can be a potentially lethal condition due to the hypoxic stress placed on the body. In pregnancy, the deleterious effects can be even more catastrophic. The benefits of treatment in all patients, especially in those who are pregnant, must outweigh the inherent risks of the therapies used to treat methemoglobinemia. Case ReportWe present a case of a 26-year-old Hispanic pregnant female at 30 weeks gestation presenting to the emergency department for chest pain, hypoxia, and cyanosis. She was subsequently diagnosed with methemoglobinemia, treated with methylene blue, and admitted to the intensive care unit with toxicology and obstetrics consultations. As an outpatient, the patient underwent genetic testing and was diagnosed with homozygous cytochrome b5 reductase deficiency as the etiology of the methemoglobinemia. Why Should an Emergency Physician Be Aware of This?Methemoglobinemia is a rare, potentially lethal, but treatable condition. In the setting of pregnancy, methemoglobinemia can pose a significant risk to the mother and fetus by causing acute hypoxia. Because methemoglobinemia can be acquired or congenital, treatments vary based on the etiology. Methylene blue is the mainstay treatment for symptomatic methemoglobinemia of levels > 20%. The teratogenic risks of methylene blue require risk−benefit analysis and discussion with the patient before utilization. Systemic maternal administration is theorized to be of lowest risk to the fetus. In this case, methylene blue was used safely as an emergent therapy for congenital methemoglobinemia during pregnancy.

S-Nitrosoglutathione Reductase (GSNOR) Deficiency Results in Secondary Hypogonadism

BackgroundExcess reactive oxygen species and reactive nitrogen species are implicated in male infertility and impaired spermatogenesis. AimTo investigate the effect of excess reactive nitrogen species and nitrosative stress on testicular function and the hypothalamic-pituitary-gonadal axis using the S-nitrosoglutathione reductase-null (Gsnor−/−) mouse model. MethodsTestis size, pup number, and epididymal sperm concentration and motility of Gsnor−/− mice were compared with those of age-matched wild-type (WT) mice. Reproductive hormones testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone were compared in Gsnor−/− and WT mice. Immunofluorescence for Gsnor−/− and WT testis was performed for 3β-hydroxysteroid dehydrogenase and luteinizing hormone receptor (LHR) and compared. Human chorionic gonadotropin and gonadotropin-releasing hormone stimulation tests were performed to assess and compare testicular and pituitary functions of Gsnor−/− and WT mice. OutcomesEvaluation of fertility and reproductive hormones in Gsnor−/− vs WT mice. Response of Gsnor−/− and WT mice to human chorionic gonadotropin and gonadotropin-releasing hormone to evaluate LH and T production. ResultsGsnor−/− mice had smaller litters (4.2 vs 8.0 pups per litter; P < .01), smaller testes (0.08 vs 0.09 g; P < .01), and decreased epididymal sperm concentration (69 vs 98 × 106; P < .05) and motility (39% vs 65%; P < .05) compared with WT mice. Serum T (44.8 vs 292.2 ng/dL; P < .05) and LH (0.03 vs 0.74 ng/mL; P = .04) were lower in Gsnor−/− than in WT mice despite similar follicle-stimulating hormone levels (63.98 vs 77.93 ng/mL; P = .20). Immunofluorescence of Gsnor−/− and WT testes showed similar staining of 3β-hydroxysteroid dehydrogenase and LHR. Human chorionic gonadotropin stimulation of Gsnor−/− mice increased serum T (>1,680 vs >1,680 ng/dL) and gonadotropin-releasing hormone stimulation increased serum LH (6.3 vs 8.9 ng/mL; P = .20) similar to WT mice. Clinical TranslationThese findings provide novel insight to a possible mechanism of secondary hypogonadism from increased reactive nitrogen species and excess nitrosative stress. Strengths and LimitationsLimitations of this study are its small samples and variability in hormone levels. ConclusionDeficiency of S-nitrosoglutathione reductase results in secondary hypogonadism, suggesting that excess nitrosative stress can affect LH production from the pituitary gland.Masterson TA, Arora H, Kulandavelu S, et al. S-Nitrosoglutathione Reductase (GSNOR) Deficiency Results in Secondary Hypogonadism. J Sex Med 2018;15:654–661.