The cobalamin type C deficiency is a rare condition that results from impaired biosynthesis of both methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl). Hemizygous mutations of the HCFC1 gene explain the majority of clinically and biologically compatible cblC patients without MMACHC mutations (OMIM 309541). We report a family with two maternal half-brothers with multiple congenital anomalies and HCFC1 gene mutation in the second Kelch domain. Both presented with dysmorphic features (flat profile, cleft lip for one), increased nuchal translucency, prenatal onset microcephaly and hypospadias. Additionally to early onset intractable epilepsy and profound neurocognitive impairment, this familial observation suggests that HCFC1 gene should be considered in boys with midline malformations, even without proven cobalamin C deficiency.

Introduction: Patients with methylmalonic acidemia (MMA) may develop many complications despite medical treatment, in particular, severe central nervous system damage and chronic kidney disease (CKD). A kidney transplant may partially correct the metabolic dysfunctions. Liver, kidney and combined liver-kidney transplantations have been advocated but no guidelines are available to identify the most suitable organ to transplant. Patients and methods: Four patients with MMA (mut degrees phenotype) received a kidney graft because of repeated metabolic decompensations, with progression to CKD in 3 patients (end-stage kidney disease in two patients and CKD stage III in one patient with an estimated glomerular filtration rate [eGFR] of 40 ml/min/1.73 m(2)) but normal renal function in one (eGFR of 93 ml/min/1.73 m(2)) before transplantation.Results: The medium age at transplantation was 7.9 y (5-10.2) and the median follow-up was 2.8 years (1.8-4.6). Renal transplantation improved the relevant metabolic parameters in 4/4 patients and renal function in the patients with CKD. Plasma and urinary MMA levels immediately decreased and remained normal or subnormal (mean values of plasma MMA before transplantation 1530 mu mol/L versus 240 mu mol/L after transplantation, and mean values of urine MMA before transplantation 4700 mmol/mol creatinine versus 2300 mmol/mol creatinine after transplantation). No further acute metabolic decompensation was observed and protein-intake was increased from 0.60 to 0.83 g/Kg/day. One patient transplanted at age 9.7 years developed a hepatoblastoma at age 11 years with subsequent neurological complications and eventually died. The three other patients are alive. Two of them remained neurologically stable. The 3rd patient who displayed choreoathetosis transiently improved his neurological condition immediately after transplantation and then remained stable.Conclusion: Kidney transplantation represents an interesting alternative therapeutic option in methylmalonic aciduria, for renal complications but also as a "cellular therapy" that may significantly reduce metabolic decompensations and hospitalizations. However, further neurological impairment remains possible. (C) 2013 Published by Elsevier Inc.

BACKGROUND:Acute decompensation of maple syrup urine disease (MSUD) is usually treated by enteral feeding with an amino-acid mixture without leucine (Leu), valine or isoleucine. However, its administration is ineffective in cases of gastric intolerance and some adult patients refuse enteral feeding via a nasogastric tube. We developed a new parenteral amino-acid mixture for patients with MSUD.METHODS:Seventeen decompensation episodes in four adult patients with MSUD treated with a parenteral amino-acid mixture (group P) were compared to 18 previous episodes in the same patients treated by enteral feeding (group E).RESULTS:The mean Leu concentration at presentation was similar in the groups P and E (1196.9 μmol/L and 1212.2 μmol/L, respectively). The mean decrease in the Leu concentration during the first 3 days of hospitalisation was significantly higher in group P than group E (p = 0.0026); there were no side effects. The mean duration of hospitalisation was similar (4 vs. 4.5 days, p = NS). No patient in group P deteriorated whereas one patient in group E required dialysis.CONCLUSION:This new parenteral amino-acid mixture is safe and allows efficient Leu concentration decrease during acute MSUD decompensation episodes in adults. Its use avoids the need for nasogastric tube insertion.

BACKGROUND:Aromatic amino acid decarboxylase (AADC) deficiency is a rare autosomal recessive disorder resulting in a combined dopamine and serotonin deficiency. About 50% of the cases set in the neonatal period. Here, we report an atypical clinical presentation with moderate symptoms.PATIENT:At 10months old, the patient presented paroxysmal eye movements without seizures, and feeding difficulties which were attributed to gastroesophageal reflux. She was investigated at the age of 7years, because of orofacial dyspraxia, hypomimie, axial hypotonia and focal segmental dystonia, bilateral ptosis, without evidence for cognitive impairment.RESULTS:HVA [110nM; (reference value (rv): 202-596)] and HIAA (12nM; rv: 87-366) decreased, OMD (520nM; rv: 5-60) and 5-HTP (56nM; rv: 2-16) increased in CSF. We confirmed the diagnosis of AADC deficiency because the activity in plasma was low: 4pmol/min/ml; rv: 16-137. The kinetic analysis revealed a sixfold increase in the apparent affinity for L-dopa (4.26mM; control=0.71), but the V (max) was unchanged (37.5pmol dopamine/min/ml; control=39.1), suggesting a modification in the substrate binding-site. Molecular analysis revealed two heterozygous mutations in the DDC gene: c1040G > A; pR347Q already described, and a novel mutation c478C > T, pR160W.CONCLUSION:(1) CSF neurotransmitters metabolites suggested a moderate AADC deficiency; (2) The initial velocity saturation curve for L-dopa displayed a cooperative ligand binding behavior, in keeping with the modifications of the three-dimensional structure, induced by the amino acid substitutions (3) The treatment combination of L-dopa with pyridoxine dramatically improved the quality of life, the fatigability, and the paroxysmal eye movements.

Background: Deficiency of mitochondria] trifunctional protein (MTP) is caused by mutations in the HADHA and HADHB genes, which have been mostly delineated at the genomic DNA level and have not been always elucidatedAim: To identify mutations in a French cohort of 52 MTP deficient patients and the susceptibility of mutations generating premature termination codons (PTCs) to the nonsense mRNA mediated decay (NMD).Methods: Mutation screening in fibroblasts was performed at the cDNA level and real-time RT-PCR was used to compare the levels of the different PTC-bearing mRNAs before and after a treatment of fibroblasts by emetine, a translation inhibitor.Results: A mutation detection rate of 100% was achieved. A total of 22 novel mutations were identified, including a large-sized genomic deletion in HADHB gene. A high proportion of all identified mutations were non-sense, frameshift and splicing mutations, generating (PTCs), distributed essentially on HADHA coding regions. We could demonstrate that the majority of mutations resulting in PTCs conform to the established rules governing the susceptibility to NMD.Conclusion: Our results emphasize the value of cDNA analysis in the characterization of HADHA and HADHB mutations and further strengthen the model of haploinsufficiency as a major pathomechanism in MTP defects. 2011 Elsevier Inc. All rights reserved.

BACKGROUND:Sedoheptulose, arabitol, ribitol, and erythritol have been identified as key diagnostic metabolites in TALDO deficiency. METHOD:Urine from 6 TALDO-deficient patients and TALDO-deficient knock-out mice were analyzed using ¹H-NMR spectroscopy and GC-mass spectrometry. RESULTS:Our data confirm the known metabolic characteristics in TALDO-deficient patients. The β-furanose form was the major sedoheptulose anomer in TALDO-deficient patients. Erythronic acid was identified as a major abnormal metabolite in all patients and in knock-out TALDO mice implicating an as yet unknown biochemical pathway in this disease. A putative sequence of enzymatic reactions leading to the formation of erythronic acid is presented. The urinary concentration of the citric acid cycle intermediates 2-oxoglutaric acid and fumaric acid was increased in the majority of TALDO-deficient patients but not in the knock-out mice. CONCLUSION:Erythronic acid is a novel and major hallmark in TALDO deficiency. The pathway leading to its production may play a role in healthy humans as well. In TALDO-deficient patients, there is an increased flux through this pathway. The finding of increased citric acid cycle intermediates hints toward a disturbed mitochondrial metabolism in TALDO deficiency.

Aims: Ornithine delta-aminotransferase (OAT) deficiency causes gyrate atrophy (GA) of the retina, as a consequence of high plasma ornithine concentrations. Because creatine synthesis requires the conversion of arginine and glycine into ornithine and guanidinoacetate, high ornithine concentration inhibits this reaction thus causing secondary creatine deficiency. The aim of this study was to evaluate the neuropsychological features and creatine metabolism in patients with GA.Methods: The study involved 7 GA patients, aged from I I to 27 years who underwent neuropsychological evaluation and cerebral proton magnetic resonance spectroscopy (MRS).Results: Neurocognitive impairment was found in 5/7 patients, including mental retardation (3/7), school failure (1/7), major visuospatial dyspraxia (1/7), aggressive behavior (3/7) and epilepsy (2/7). Two patients had normal neuropsychological evaluation. Cerebral proton magnetic resonance spectroscopy revealed a profound creatine deficiency in all patients. MRS data were confirmed by decreased levels of creatine and/or guanidinoacetate in plasma and urine in all patients.Conclusions: In our group of patients with CA. we found a high prevalence of neurological impairment, not reported so far, and possibly related to secondary creatine deficiency and hyperornithinemia. We propose to treat mentally retarded GA patients with high doses of creatine, as it may normalize brain creatine levels and help to reduce ornithine levels. (C) 2009 Elsevier Inc. All rights reserved.

An adult patient with methylmalonic aciduria due to defective cobalamin synthesis (CblA) responsive to vitamin B(12) presented suddenly with severe visual impairment ascribed to optic atrophy followed by a fatal multiorgan failure and lactic acidosis but low methylmalonic acid in plasma and urine. Multiple deficiency of oxidative phosphorylation was found in the patient's liver. We suggest that patients with B(12)-sensitive methylmalonic aciduria who have a milder clinical course should be carefully monitored for long-term complications.