A Turkish case with molybdenum cofactor deficiency

Late-Onset Molybdenum Cofactor Deficiency Type A: A Treatable Cause of Developmental Delay

Molybdenum cofactor deficiency classically presents in neonates with intractable seizures; however, milder cases generally present before age 2 years with developmental delays and may go undiagnosed. Early diagnosis, and safe, US Food and Drug Administration-approved substrate replacement are critical to preserve neurologic function. This article discusses 2 children who presented with late-onset molybdenum cofactor deficiency type A.

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.

[Urinary protein detection by iTRAQ® associated with renal transplant complications and its modification with therapy]

BACKGROUND

After renal transplant, surgical, infection complications, as well as graft rejection may occur; early detection through non-invasive markers is the key to change therapy and avoid biopsy.

OBJECTIVE

The aime of the study is to determine urine protein profiles in patients undergoing renal transplant with complications and detect its variation when therapy is modified.

MATERIAL AND METHODS

Urine samples were collected from patients prior the transplant and various postoperative stages. Urinary protein profiles were obtained by peptide labeling using isobaric isotopes for relative quantification (iTRAQ(®)).

RESULTS

A total of 22 patients were included, of whom 12 developed post-transplant complication: 2 with graft rejection (one male and one female) and 10 (6 males and 4 females) in the group of post-transplant infections. Using iTRAQ(®) 15/345 and 28/113 proteins were identified and fulfilled the acceptance criteria, in graft rejection and post-transplant infections group, respectively.

CONCLUSIONS

Albumin was the only protein found in both groups, the remaining proteins were different. The 5 proteins with higher scores in graft rejection were: alpha-1-microglobulin, 5'-nucleotidase cytosolic III, retinol-binding protein 4, membrane protein palmitoylated 4, and serine carboxypeptidase, while post-transplant infections were: mitochondrial acetyl-coenzyme A synthetase, putative adenosyl homocysteinase 2, zinc finger protein GLIS1, putative protein FAM157B, and zinc finger protein 615. It remains to elucidate the involvement of each of these in patients with renal transplantation.

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.

Functional deficiencies of sulfite oxidase: Differential diagnoses in neonates presenting with intractable seizures and cystic encephalomalacia

Sulfite oxidase is a mitochondrial enzyme encoded by the SUOX gene and essential for the detoxification of sulfite which results mainly from the catabolism of sulfur-containing amino acids. Decreased activity of this enzyme can either be due to mutations in the SUOX gene or secondary to defects in the synthesis of its cofactor, the molybdenum cofactor. Defects in the synthesis of the molybdenum cofactor are caused by mutations in one of the genes MOCS1, MOCS2, MOCS3 and GEPH and result in combined deficiencies of the enzymes sulfite oxidase, xanthine dehydrogenase and aldehyde oxidase. Although present in many ethnic groups, isolated sulfite oxidase deficiency and molybdenum cofactor deficiency are rare inborn errors of metabolism, which makes awareness of key clinical and laboratory features of affected individuals crucial for early diagnosis. We report clinical, radiologic, biochemical and genetic data on a Brazilian and on a Turkish child with sulfite oxidase deficiency due to the isolated defect and impaired synthesis of the molybdenum cofactor, respectively. Both patients presented with early onset seizures and neurological deterioration. They showed no sulfite oxidase activity in fibroblasts and were homozygous for the mutations c.1136A>G in the SUOX gene and c.667insCGA in the MOCS1 gene, respectively. Widely available routine laboratory tests such as assessment of total homocysteine and uric acid are indicated in children with a clinical presentation resembling that of hypoxic ischemic encephalopathy and may help in obtaining a tentative diagnosis locally, which requires confirmation by specialized laboratories.