Molybdenum cofactor deficiency: clinical features in a Turkish patient

Common proteins analysis of different mammals' mature milk by 4D-Label-Free

The milk proteins from samples of 13 different animals were identified utilizing 4D-Label-Free proteomics technology, leading to the identification of a substantial number of proteins. Among the various samples, Chinese people (CHP) milk proteins exhibited the highest count, with 1149 distinct proteins. Simultaneously, we identified common proteins present in these animal milk. It's notable presence in goat milk contributes to enhancing infant infection resistance, showcasing the beneficial role of lactoperoxidase. Galectin-3 binding protein (Gal-3BP) and tetraspanin in human milk are significantly higher than those in other animals, which determine the prominent antiviral effect of human milk and the important processes related to cell transduction. Furthermore, human milk, camel milk, goat milk and sheep milk proved to be rich sources of milk fat globule membrane (MFGM) proteins. The insights obtained from this study can serve as a foundational framework for exploring the role of different animal milk proteins in disease treatment and the composition of infant formula.

Molybdenum Cofactor Deficiency in Humans

Molybdenum cofactor (Moco) deficiency (MoCD) is characterized by neonatal-onset myoclonic epileptic encephalopathy and dystonia with cerebral MRI changes similar to hypoxic-ischemic lesions. The molecular cause of the disease is the loss of sulfite oxidase (SOX) activity, one of four Moco-dependent enzymes in men. Accumulating toxic sulfite causes a secondary increase of metabolites such as S-sulfocysteine and thiosulfate as well as a decrease in cysteine and its oxidized form, cystine. Moco is synthesized by a three-step biosynthetic pathway that involves the gene products of MOCS1, MOCS2, MOCS3, and GPHN. Depending on which synthetic step is impaired, MoCD is classified as type A, B, or C. This distinction is relevant for patient management because the metabolic block in MoCD type A can be circumvented by administering cyclic pyranopterin monophosphate (cPMP). Substitution therapy with cPMP is highly effective in reducing sulfite toxicity and restoring biochemical homeostasis, while the clinical outcome critically depends on the degree of brain injury prior to the start of treatment. In the absence of a specific treatment for MoCD type B/C and SOX deficiency, we summarize recent progress in our understanding of the underlying metabolic changes in cysteine homeostasis and propose novel therapeutic interventions to circumvent those pathological changes.

Ocular characteristics of a 6-year-Old boy with molybdenum cofactor deficiency type B

Purpose

To report a rare case of Molybdenum Cofactor Deficiency with novel ocular manifestations.

Observations

This is a case study of a 6-year-old boy who initially presented with conjunctival hyperemia and ocular pain of the left eye. Medical history revealed refractory convulsion, global developmental delay, microcephaly, feeding difficulties, aphasia, and spastic quadriplegia, as well as pathogenic MOCS2 mutations, indicating the diagnosis of molybdenum cofactor deficiency (MoCD). This case report highlights detailed ocular manifestations of late-onset MoCD-B, ectopia lentis of bilateral eyes, spherophakia, hyperemia, secondary glaucoma, cyclodialysis, and retinal detachment of the left eye, which will help further understanding of MoCD.

Conclusions and importance

MoCD as a rare genetic disease is tend to be easily neglected. The ophthalmic examination could provide important evidence for early diagnosis.

Coexistence of molybdenum cofactor deficiency type A and hypertrophic pyloric stenosis, a new case

Molybdenum cofactor deficiency is a rare neurometabolic disease that is usually characterized by seizures, abnormal muscle tonus, developmental delay and poor nutrition, and is seen soon after birth. Pyloric stenosis causes serious vomiting in the first months of life. The presence of neurologic damage in molybdenum cofactor deficiency and possible abnormal innervations may cause pyloric stenosis; however, the pathogenesis is unclear. Pyloric stenosis with molybdenum cofactor deficiency has been described in two cases. Herein, we report the third case and suggest that hypertrophic pyloric stenosis should be kept in mind as a clinical manifestation of molybdenum cofactor deficiency.

A neonate with molybdenum cofactor deficiency type B

Molybdenum cofactor deficiency (MoCD) is an autosomal recessive disease which leads to a combined deficiency of molybdenum cofactor dependent enzymes. There are four different genes in molybdenum cofactor biosynthesis, MOCS1, MOCS2, MOCS3, GEPH. The patients with MOCS2 homozygous mutation who onset in the neonatal period always have severe seizures, feeding difficulties, progressive neurological deterioration. The incidence of the disease is low, and certain types have never been reported in China. Here, we present a Chinese term infant with MOCS2 who presented seizure, intolerance to feed and hypotonia on the third day after birth. Treatment included intravenous nutrition, antibiotic, and anticonvulsant therapy. The seizure can't be controlled and her encephalopathy progressed. A homozygous mutation in exon 4 in MOSC2 gene was found and the mutation of the patient has not been reported before. In conclusion, the patients with MOCS2 who onset in neonatal period often shows uncontrolled seizure, feeding difficulties, hypotonia and early death. And the MRI of them shows severe encephalomalacia. There is no treatment for the disease by now, but early diagnosis and genetic detection can give the family genetic counseling.

The Clinical and Molecular Characteristics of Molybdenum Cofactor Deficiency Due to MOCS2 Mutations

BACKGROUND

We explored the clinical and molecular characteristics of molybdenum cofactor deficiency due to MOCS2 muations.

METHODS

We summarize the genetic and clinical findings of previously reported patients with a MOCS2 mutation. We also present a new patient with novel neuroradiological findings associated with molybdenum cofactor deficiency due to a novel homozygous variant in the 5' untranslated region of the MOCS2 gene.

RESULTS

The study population comprised 35 patients with a MOCS2 gene mutation. All reported children had delayed motor milestones. The major initial symptom was seizures in neonatal period. Facial dysmorphism was present in 61% of the patients. Only one patient had ectopia lentis. Agenesis of the corpus callosum and an associated interhemispheric cyst in our case are novel neuroradiological findings.

CONCLUSIONS

The occurrence of neonatal seizures and feeding difficulties can be the first clinical signs of molybdenum cofactor deficiency. Although there is no effective therapy for this condition, early diagnosis and genetic analysis of these lethal disorders facilitate adequate genetic counseling.

Critical appraisal of genotype assessment in molybdenum cofactor deficiency

INTRODUCTION

Molybdenum cofactor deficiency (MoCD) is an ultra-orphan, life-threatening disease. Substrate substitution therapy has successfully been performed in single cases of MoCD type A and clinical trials are underway for drug registration. We present an innovative approach for classification of genotype severity to test the hypothesis that milder sequence variants in MoCD result in a less severe disease phenotype quantitated by patient survival.

METHODS

All available worldwide published cases with clinical and genetic data were included (n = 40). We stratified the already published disease causing sequence variants as mild or severe with the use of in silico prediction programs, where possible and assessed the possible impact of the variants on the expression of the gene or function of the expressed protein. In a compound heterozygous situation the mildest sequence variant determined the genotype. Subsequently, clinical manifestations and outcomes of both groups were compared.

RESULTS

Patients with a severe genotype showed a median survival of 15 months and had a lower probability of survival compared to patients with mild genotypes who were all alive at last reported follow-up (p = 0.0203, Log-rank test).

DISCUSSION

The severity of the genotype assessed by in silico prediction and further classification explained survival in molybdenum cofactor deficiency and may therefore be considered a confounder for the outcome of therapeutic clinical trials requiring adjustment in the clinical trial design or analysis. These results should further be investigated by future in vitro or in vivo functional studies. Caution should be taken with this approach for the classification of variants in molecular genetic diagnostics or genetic counseling.

Higher susceptibility of cerebral cortex and striatum to sulfite neurotoxicity in sulfite oxidase-deficient rats

Patients affected by sulfite oxidase (SO) deficiency present severe seizures early in infancy and progressive neurological damage, as well as tissue accumulation of sulfite, thiosulfate and S-sulfocysteine. Since the pathomechanisms involved in the neuropathology of SO deficiency are still poorly established, we evaluated the effects of sulfite on redox homeostasis and bioenergetics in cerebral cortex, striatum, cerebellum and hippocampus of rats with chemically induced SO deficiency. The deficiency was induced in 21-day-old rats by adding 200ppm of tungsten, a molybdenum competitor, in their drinking water for 9weeks. Sulfite (70mg/kg/day) was also administered through the drinking water from the third week of tungsten supplementation until the end of the treatment. Sulfite decreased reduced glutathione concentrations and the activities of glutathione reductase and glutathione S-transferase (GST) in cerebral cortex and of GST in cerebellum of SO-deficient rats. Moreover, sulfite increased the activities of complexes II and II-III in striatum and of complex II in hippocampus, but reduced the activity of complex IV in striatum of SO-deficient rats. Sulfite also decreased the mitochondrial membrane potential in cerebral cortex and striatum, whereas it had no effect on mitochondrial mass in any encephalic tissue evaluated. Finally, sulfite inhibited the activities of malate and glutamate dehydrogenase in cerebral cortex of SO-deficient rats. Taken together, our findings indicate that cerebral cortex and striatum are more vulnerable to sulfite-induced toxicity than cerebellum and hippocampus. It is presumed that these pathomechanisms may contribute to the pathophysiology of neurological damage found in patients affected by SO deficiency.

Neurologic injury in isolated sulfite oxidase deficiency

BACKGROUND

We review clinical, neuroimaging, and genetic information on six individuals with isolated sulfite oxidase deficiency (ISOD).

METHODS

All patients were examined, and clinical records, biochemistry, neuroimaging, and sulfite oxidase gene (SUOX) sequencing were reviewed.

RESULTS

Data was available on six individuals from four nuclear families affected by ISOD. Each individual began to seize within the first week of life. neurologic development was arrested at brainstem reflexes, and severe microcephaly developed rapidly. neuroimaging within days of birth revealed hypoplasia of the cerebellum and corpus callosum and damage to the supratentorial brain looking like severe hypoxic-ischemic injury that evolved into cystic hemispheric white matter changes. Affected individuals all had elevated urinary S-sulfocysteine and normal urinary xanthine and hypoxanthine levels diagnostic of ISOD. Genetic studies confirmed SUOX mutations in four patients.

CONCLUSIONS

ISOD impairs systemic sulfite metabolism, and yet this genetic disease affects only the brain with damage that is commonly confused with the clinical and radiologic features of severe hypoxic-ischemic encephalopathy.

Lésions neurologiques dans le déficit isolé en sulfite oxydase.

Review article: recent advances in pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in inflammatory bowel disease

BACKGROUND

Azathioprine and mercaptopurine have a pivotal role in the treatment of inflammatory bowel disease (IBD). However, because of their complex metabolism and potential toxicities, optimal use of biomarkers to predict adverse effects and therapeutic response is paramount.

AIM

To provide a comprehensive review focused on pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in IBD.

METHODS

A literature search up to July 2015 was performed in PubMed using a combination of relevant MeSH terms.

RESULTS

Pre-treatment thiopurine S-methyltransferase typing plus measurement of 6-tioguanine nucleotides and 6-methylmercaptopurine ribonucleotides levels during treatment have emerged with key roles in facilitating safe and effective thiopurine therapy. Optimal use of these tools has been shown to reduce the risk of adverse effects by 3-7%, and to improve efficacy by 15-30%. For the introduction of aldehyde oxidase (AOX) into clinical practice, the association between AOX activity and AZA dose requirements should be positively confirmed. Inosine triphosphatase assessment associated with adverse effects also shows promise. Nucleoside diphosphate-linked moiety X-type motif 15 variants have been shown to predict myelotoxicity on thiopurines in East Asian patients. However, the impact of assessments of xanthine oxidase, glutathione S-transferase, hypoxanthine guanine phosphoribosyltransferase and inosine monophosphate dehydrogenase appears too low to favour incorporation into clinical practice.

CONCLUSIONS

Measurement of thiopurine-related enzymes and metabolites reduces the risk of adverse effects and improves efficacy, and should be considered part of standard management. However, this approach will not predict or avoid all adverse effects, and careful clinical and laboratory monitoring of patients receiving thiopurines remains essential.

Efficacy and safety of cyclic pyranopterin monophosphate substitution in severe molybdenum cofactor deficiency type A: a prospective cohort study

BACKGROUND

Molybdenum cofactor deficiency (MoCD) is characterised by early, rapidly progressive postnatal encephalopathy and intractable seizures, leading to severe disability and early death. Previous treatment attempts have been unsuccessful. After a pioneering single treatment we now report the outcome of the complete first cohort of patients receiving substitution treatment with cyclic pyranopterin monophosphate (cPMP), a biosynthetic precursor of the cofactor.

METHODS

In this observational prospective cohort study, newborn babies with clinical and biochemical evidence of MoCD were admitted to a compassionate-use programme at the request of their treating physicians. Intravenous cPMP (80-320 μg/kg per day) was started in neonates diagnosed with MoCD (type A and type B) following a standardised protocol. We prospectively monitored safety and efficacy in all patients exposed to cPMP.

FINDINGS

Between June 6, 2008, and Jan 9, 2013, intravenous cPMP was started in 16 neonates diagnosed with MoCD (11 type A and five type B) and continued in eight type A patients for up to 5 years. We observed no drug-related serious adverse events after more than 6000 doses. The disease biomarkers urinary S-sulphocysteine, xanthine, and urate returned to almost normal concentrations in all type A patients within 2 days, and remained normal for up to 5 years on continued cPMP substitution. Eight patients with type A disease rapidly improved under treatment and convulsions were either completely suppressed or substantially reduced. Three patients treated early remain seizure free and show near-normal long-term development. We detected no biochemical or clinical response in patients with type B disease.

INTERPRETATION

cPMP substitution is the first effective therapy for patients with MoCD type A and has a favourable safety profile. Restoration of molybdenum cofactor-dependent enzyme activities results in a greatly improved neurodevelopmental outcome when started sufficiently early. The possibility of MoCD type A needs to be urgently explored in every encephalopathic neonate to avoid any delay in appropriate cPMP substitution, and to maximise treatment benefit.

FUNDING

German Ministry of Education and Research; Orphatec/Colbourne Pharmaceuticals.

Molybdenum cofactor deficiency: review of 12 cases (MoCD and review)

Molybdenum cofactor deficiency is a rare inborn error of metabolism. The major clinical symptoms are intractable neonatal seizures, progressive encephalopathy, facial dysmorphic features and feeding difficulties. Most of the patients are misdiagnosed as hypoxic ischemic encephalopathy. The majority of patients have mutations in the MOCS1 and MOCS2 genes. Although the therapeutic treatment strategies have not been improved, genetic analysis is essential to elucidate the disease. Here, we report a review of 12 patients with Molybdenum cofactor deficiency reported from Turkey.

The association of molybdenum cofactor deficiency and pyloric stenosis

Molybdenum cofactor deficiency (MoCD) is a rare autosomal recessive disorder that may present during the neonatal period with intractable seizures. Co-existence of MoCD and pyloric stenosis is previously reported as a coincidence or common etiology. The etiology of the two conditions is unclear; however, reports demonstrate neuronal deficiency in both. We report a neonate who was diagnosed with MoCD and hypertrophic pyloric stenosis.

Molybdenum cofactor deficiency mimics cerebral palsy: differentiating factors for diagnosis

We describe an infant with molybdenum cofactor deficiency, initially diagnosed as cerebral palsy. Clinical features of molybdenum cofactor deficiency, e.g., neonatal seizures, hypertonus/hypotonus, and feeding and respiratory difficulties, resemble those of neonatal hypoxic-ischemic encephalopathy. Our patient, a 2-year-old boy, presented with spastic quadriplegia and mental retardation. He manifested intractable neonatal seizures and diffuse cerebral atrophy. When admitted with bronchitis at age 18 months, his uric acid levels in blood and urine were undetectable. A urinary sulfite test revealed positive results. Further tests revealed elevated urinary levels of xanthine, hypoxanthine, and S-sulfocystein. Sequencing of the MOCS2A gene revealed heterozygosity for c.[265T>C] + [266A>G], diagnosed as molybdenum cofactor deficiency type B. Neonatal seizures, progressive cerebral atrophy, and low serum levels of uric acid may provide diagnostic clues in patients with cerebral palsy of undetermined cause.

Isolated neonatal seizures: when to suspect inborn errors of metabolism

Neonatal seizures are common, and often comprise the first clinical indicator of central nervous system dysfunction. Although most neonatal seizures are secondary to processes such as hypoxic-ischemic injury, infection, or cortical malformations (which are readily identifiable through routine testing and imaging), seizures secondary to inborn errors of metabolism can be much more difficult to diagnose, and thus a high index of suspicion is required. The early diagnosis of inborn errors of metabolism is crucial, considering that many can receive effective treatment (e.g., dietary supplementation or restriction) with favorable long-term outcomes. This review emphasizes the importance of considering inborn errors of metabolism in the differential diagnosis of neonatal seizures, discusses red flags for inborn errors of metabolism as a cause of neonatal seizures, and provides an overview of diagnoses and treatments of inborn errors of metabolism most commonly associated with neonatal seizures.

Clinical neuroimaging features and outcome in molybdenum cofactor deficiency

Molybdenum cofactor deficiency predominantly affects the central nervous system. There are limited data on long-term outcome or brain magnetic resonance imaging (MRI) features. We examined the clinical, brain MRI, biochemical, genetic, and electroencephalographic features and outcome in 8 children with a diagnosis of molybdenum cofactor deficiency observed in our institution over 10 years. Two modes of presentation were identified: early (classical) onset with predominantly epileptic encephalopathy in 6 neonates, and late (atypical) with global developmental impairment in 2 children. Children in both groups had varying degrees of motor, language, and visual impairment. There were no deaths. Brain MRI demonstrated cerebral infarction in all but one child in the atypical group. Distinctive features were best observed on early brain MRI: acute symmetrical involvement of the globus pallidi and subthalamic regions coexisting with older cerebral hemisphere infarction, chronic lesions suggestive of a prenatal insult, pontocerebellar hypoplasia with retrocerebellar cyst, and presence of a distinctive band at the cortical/subcortical white matter. Sequential imaging revealed progressive pontine atrophy and enlargement of retrocerebellar cyst. The brain MRI of one child with atypical presentation (verbal dyspraxia, lens dislocation) showed symmetrical cerebellar deep nuclei signal abnormality without cerebral infarction. Imaging pattern on early brain MRI (<1 week) may prompt the diagnosis, potentially allowing early treatment and disease modifications.

Prenatal brain disruption in molybdenum cofactor deficiency

Molybdenum cofactor deficiency is a rare autosomal recessive disorder that may present during the neonatal period with intractable seizures and be mistaken for ischemic encephalopathy. We describe a patient whose prenatal sonography at 35 weeks' gestation revealed diffuse brain damage with multiple subcortical cavities, ventriculomegaly, dysgenesis of the corpus callosum, and a hypoplastic cerebellum with an enlarged cisterna magna. Magnetic resonance imaging (MRI) later revealed brain atrophy, and multicystic encephalomalacia with hypoplastic vermis and cerebellum. Neurological examination at 10 months showed microcephaly, profound mental retardation, and spasticity. Uric acid was low, and taurine and xanthine were increased in the urine. A sulfite test was positive. The diagnosis of molybdenum cofactor deficiency was made. Sulfite oxidase activity in fibroblasts was undetectable. The patient was found to be homozygous for the 251-418del in the MOCS1 gene. This is the first description of the prenatal development of severe brain disruption in molybdenum cofactor deficiency.

Maternal uniparental isodisomy is responsible for serious molybdenum cofactor deficiency

Molybdenum cofactor (MoCo) deficiency is a rare autosomal recessive inherited metabolic disorder resulting in the combined deficiency of aldehyde oxidase, xanthine dehydrogenase, and sulfite oxidase. We report a male infant with MoCo deficiency whose clinical findings consisted of microcephaly, intractable seizures soon after birth, feeding difficulties, and developmental delay. Sequencing of MOCS1, MOCS2, and GEPH genes, and single nucleotide polymorphism genotyping array analysis showed, to our knowledge, unusual inheritance of MoCo deficiency/maternal uniparental isodisomy for the first time in the literature. At 10 months of age, he now has microcephaly and developmental delay, and his seizures are controlled with phenobarbital, clonozepam, and vigabatrin therapy.

Successful treatment of molybdenum cofactor deficiency type A with cPMP

Molybdenum cofactor deficiency (MoCD) is a rare metabolic disorder characterized by severe and rapidly progressive neurologic damage caused by the functional loss of sulfite oxidase, 1 of 4 molybdenum-dependent enzymes. To date, no effective therapy is available for MoCD, and death in early infancy has been the usual outcome. We report here the case of a patient who was diagnosed with MoCD at the age of 6 days. Substitution therapy with purified cyclic pyranopterin monophosphate (cPMP) was started on day 36 by daily intravenous administration of 80 to 160 microg of cPMP/kg of body weight. Within 1 to 2 weeks, all urinary markers of sulfite oxidase (sulfite, S-sulfocysteine, thiosulfate) and xanthine oxidase deficiency (xanthine, uric acid) returned to almost normal readings and stayed constant (>450 days of treatment). Clinically, the infant became more alert, convulsions and twitching disappeared within the first 2 weeks, and an electroencephalogram showed the return of rhythmic elements and markedly reduced epileptiform discharges. Substitution of cPMP represents the first causative therapy available for patients with MoCD. We demonstrate efficient uptake of cPMP and restoration of molybdenum cofactor-dependent enzyme activities. Further neurodegeneration by toxic metabolites was stopped in the reported patient. We also demonstrated the feasibility to detect MoCD in newborn-screening cards to enable early diagnosis.

Pharmacogenomics in the treatment of inflammatory bowel disease

In recent years, the benefits of early aggressive treatment paradigms for inflammatory bowel disease have emerged. Symptomatic improvement is no longer considered adequate; instead, the aim of treatment has become mucosal healing and altered natural history. Nonetheless, we still fail to achieve these end points in a large number of our patients. There are many reasons why patients fail to respond or develop toxicity when exposed to drugs used for inflammatory bowel disease, but genetic variation is likely to account for a significant proportion of this. Some examples, notably thiopurine methyltransferase polymorphism in thiopurine treatment, are already established in clinical practice. We present a review of the expanding literature in this field, highlighting many interesting developments in pharmacogenomics applied to inflammatory bowel disease and, where possible, providing guidance on the translation of these developments into clinical practice.

Novel pharmacogenetic markers for treatment outcome in azathioprine-treated inflammatory bowel disease

BACKGROUND

Azathioprine (AZA) pharmacogenetics are complex and much studied. Genetic polymorphism in TPMT is known to influence treatment outcome. Xanthine oxidase/dehydrogenase (XDH) and aldehyde oxidase (AO) compete with TPMT to inactivate AZA.

AIM

To assess whether genetic polymorphism in AOX1, XDH and MOCOS (the product of which activates the essential cofactor for AO and XDH) is associated with AZA treatment outcome in IBD.

METHODS

Real-time PCR was conducted for a panel of single nucleotide polymorphism (SNPs) in AOX1, XDH and MOCOS using TaqMan SNP genotyping assays in a prospective cohort of 192 patients receiving AZA for IBD.

RESULTS

Single nucleotide polymorphism AOX1 c.3404A > G (Asn1135Ser, rs55754655) predicted lack of AZA response (P = 0.035, OR 2.54, 95%CI 1.06-6.13) and when combined with TPMT activity, this information allowed stratification of a patient's chance of AZA response, ranging from 86% in patients where both markers were favourable to 33% where they were unfavourable (P < 0.0001). We also demonstrated a weak protective effect against adverse drug reactions (ADRs) from SNPs XDH c.837C > T (P = 0.048, OR 0.23, 95% CI 0.05-1.05) and MOCOS c.2107A > C, (P = 0.058 in recessive model, OR 0.64, 95%CI 0.36-1.15), which was stronger where they coincided (P = 0.019).

CONCLUSION

These findings have important implications for clinical practice and our understanding of AZA metabolism.