[Consensus on screening, diagnosis and treatment of multiple acyl-CoA dehydrogenase deficiency].

Multiple acyl-CoA dehydrogenase deficiency (MADD), also known as glutaricacidemia type II, is a relatively common disorder of fatty acid oxidation metabolism. The clinical manifestations are highly heterogeneous, symptoms can develop from newborn to adulthood. Neonatal onset type is more serious with high mortality. The symptoms of late onset patients include lipid deposition myopathy and vomiting, liver disease, and encephalopathy. Analysis of blood acyl carnitine spectrum by tandem mass spectrometry can be used for the screening. Late onset patients have relatively good prognosis with vitamin B2 treatment. The purpose of this consensus is to standardize the diagnosis, treatment and management of MADD, so as to improve the prognosis of patients and reduce death and disability.

Late-onset MADD: a rare cause of cirrhosis and acute liver failure?

Late-onset multiple acyl-CoA dehydrogenase deficiency (MADD) is a severe inborn error of fat metabolism. In late-onset MADD, hepatopathy in the form of steatosis is commonplace and considered a benign and stable condition that does not progress to more advanced stages of liver disease, however, progression to cirrhosis and acute liver failure (ALF) has been reported in two previous case reports. Here, we report a 22-year-old man, who suffered from late-onset MADD and died from cirrhosis and ALF. In the span of three months repeated clinical examinations, blood tests, and diagnostic imaging as well as liver biopsy revealed rapid progression of hepatopathy from steatosis to decompensated cirrhosis with portal hypertension. Routine studies for recognized etiologies found no evident cause besides MADD. This case report supports the findings of the two previous case reports and adds further evidence to the suggestion that late-onset MADD should be considered a rare cause of cirrhosis and ALF.

A case report of a mild form of multiple acyl-CoA dehydrogenase deficiency due to compound heterozygous mutations in the ETFA gene.

BACKGROUND: Multiple acyl-CoA dehydrogenase deficiency (MADD), previously called glutaric aciduria type II, is a rare congenital metabolic disorder of fatty acids and amino acids oxidation, with recessive autosomal transmission. The prevalence in the general population is estimated to be 9/1,000,000 and the prevalence at birth approximately 1/200,000. The clinical features of this disease are divided into three groups of symptoms linked to a defect in electron transfer flavoprotein (ETF) metabolism. In this case report, we present new pathogenic variations in one of the two ETF protein subunits, called electron transfer flavoprotein alpha (ETFA), in a childhood-stage patient with no antecedent. CASE PRESENTATION: A five-year-old child was admitted to the paediatric emergency unit for seizures without fever. He was unconscious due to hypoglycaemia confirmed by laboratory analyses. At birth, he was a eutrophic full-term new-born with a normal APGAR index (score for appearance, pulse, grimace, activity, and respiration). He had one older brother and no parental consanguinity was reported. A slight speech acquisition delay was observed a few months before his admission, but he had no schooling problems. MADD was suspected based on urinary organic acids and plasma acylcarnitine analyses and later confirmed by genetic analysis, which showed previously unreported ETFA gene variations, both heterozygous (c.354C > A (p.Asn118Lys) and c.652G > A (p.Val218Met) variations). Treatment was based on avoiding fasting and a slow carbohydrate-rich evening meal associated with L-carnitine supplementation (approximately 100 mg/kg/day) for several weeks. This treatment was maintained and associated with riboflavin supplementation (approximately 150 mg/day). During follow up, the patient exhibited normal development and normal scholastic performance, with no decompensation. CONCLUSION: This case report describes new pathogenic variations of the ETFA gene. These compound heterozygous mutations induce the production of altered proteins, leading to a mild form of MADD.

Long-term ketone body therapy of severe multiple acyl-CoA dehydrogenase deficiency: A case report.

OBJECTIVES: Multiple acyl-CoA dehydrogenase deficiency (MADD) is the most severe disorder of mitochondrial fatty acid ß-oxidation. Treatment of this disorder is difficult because the functional loss of the electron transfer flavoprotein makes energy supply from fatty acids impossible. Acetyl-CoA, provided by exogenous ketone bodies such as NaßHB, is the only treatment option in severe cases. Short-term therapy attempts have shown positive results. To our knowledge, no reports exist concerning long-term application of ketone body salts in patients with severe MADD. METHODS: This case report is a detailed retrospective metabolic analysis of a boy with severe MADD. Treatment with sodium ß-hydroxybutyrate (NaßHB) started 8 d after birth using gradually increasing doses. In the initial phase, metabolic and acid-base parameters were checked multiple times a day. After 8 y of standardized therapy with 16 g NaßHB, substitution with calcium ß-hydroxybutyrate (CaßHB) was attempted. In addition to the ß-hydroxybutyrate (ßHB) supplementation, continuous adjustments were made to the child's nutrition to provide necessary nutrients. RESULTS: Treatment with ßHB salts leads to adverse effects like gastrointestinal discomfort and alkalosis. Measured concentrations of ßHB were predominantly at 0.1 mmol/L or below detectable concentration. Nutritional therapy based on amino acid and acylcarnitine profiles is a necessary part of the therapy in MADD. CONCLUSIONS: Therapy with NaßHB is lifesaving in cases of severe MADD but can have significant adverse effects. Supplementation with CaßHB led to gastrointestinal discomfort and had no additional positive clinical effect. The determined tolerable dose of ßHB salt for long-term therapy was not high enough for a notable increase of ßHB concentrations in blood.

Multi-organ abnormalities and mTORC1 activation in zebrafish model of multiple acyl-CoA dehydrogenase deficiency.

Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) is a severe mitochondrial disorder featuring multi-organ dysfunction. Mutations in either the ETFA, ETFB, and ETFDH genes can cause MADD but very little is known about disease specific mechanisms due to a paucity of animal models. We report a novel zebrafish mutant dark xavier (dxa(vu463) ) that has an inactivating mutation in the etfa gene. dxa(vu463) recapitulates numerous pathological and biochemical features seen in patients with MADD including brain, liver, and kidney disease. Similar to children with MADD, homozygote mutant dxa(vu463) zebrafish have a spectrum of phenotypes ranging from moderate to severe. Interestingly, excessive maternal feeding significantly exacerbated the phenotype. Homozygous mutant dxa(vu463) zebrafish have swollen and hyperplastic neural progenitor cells, hepatocytes and kidney tubule cells as well as elevations in triacylglycerol, cerebroside sulfate and cholesterol levels. Their mitochondria were also greatly enlarged, lacked normal cristae, and were dysfunctional. We also found increased signaling of the mechanistic target of rapamycin complex 1 (mTORC1) with enlarged cell size and proliferation. Treatment with rapamycin partially reversed these abnormalities. Our results indicate that etfa gene function is remarkably conserved in zebrafish as compared to humans with highly similar pathological, biochemical abnormalities to those reported in children with MADD. Altered mTORC1 signaling and maternal nutritional status may play critical roles in MADD disease progression and suggest novel treatment approaches that may ameliorate disease severity.

Cyclic vomiting syndrome masking a fatal metabolic disease.

Disorders of fatty acid oxidation are rare but can be fatal. Hypoglycaemia with acidosis is a cardinal feature. Cases may present during early childhood or can be delayed into adolescence or beyond. We present a case of multiple acyl-coenzyme A dehydrogenase deficiency (MADD), an extremely rare disorder of fatty acid oxidation. Our 20-year-old patient presented with cardiovascular collapse, raised anion gap metabolic acidosis and non-ketotic hypoglycaemia. She subsequently developed multi-organ failure and sadly died. She had a previous diagnosis of cyclic vomiting syndrome (CVS) for more than 10 years, warranting frequent hospital admissions. The association between CVS and MADD has been made before though the exact relationship is unclear. All patients with persistent severe CVS should have metabolic investigations to exclude disorders of fatty acid oxidation. In case of non-ketotic hypoglycaemia with acidosis, the patient should be urgently referred to a specialist in metabolic diseases. All practitioners should be aware of these rare disorders as a cause of unexplained acidosis.

Update on clinical aspects and treatment of selected vitamin-responsive disorders II (riboflavin and CoQ 10).

Riboflavin and ubiquinone (Coenzyme Q(10), CoQ(10)) deficiencies are heterogeneous groups of autosomal recessive conditions affecting both children and adults. Riboflavin (vitamin B(2))-derived cofactors are essential for the function of numerous dehydrogenases. Genetic defects of the riboflavin transport have been detected in Brown-Vialetto-Van Laere and Fazio-Londe syndromes (C20orf54), and haploinsufficiency of GPR172B has been proposed in one patient to cause persistent riboflavin deficiency. Mutations in the electron tranferring fravoprotein genes (ETFA/ETFB) and its dehydrogenase (ETFDH) are causative for multiple acyl-CoA dehydrogenase deficiency. Mutations in ACAD9, encoding the acyl-CoA dehydrogenase 9 protein were recently reported in mitochondrial disease with respiratory chain complex I deficiency. All these conditions may respond to riboflavin therapy. CoQ(10) is a lipid-soluble component of the cell membranes, where it functions as a mobile electron and proton carrier, but also participates in other cellular processes as a potent antioxidant, and by influencing pyrimidine metabolism. The increasing number of molecular defects in enzymes of the CoQ(10) biosynthetic pathways (PDSS1, PDSS2, COQ2, COQ6, COQ9, CABC1/ADCK3) underlies the importance of these conditions. The clinical heterogeneity may reflect blocks at different levels in the complex biosynthetic pathway. Despite the identification of several primary CoQ(10) deficiency genes, the number of reported patients is still low, and no true genotype-phenotype correlations are known which makes the genetic diagnosis still difficult. Additionally to primary CoQ(10) deficiencies, where the mutation impairs a protein directly involved in CoQ(10) biosynthesis, we can differentiate secondary deficiencies. CoQ(10) supplementation may be beneficial in both primary and secondary deficiencies and therefore the early recognition of these diseases is of utmost importance.

Use of guidelines improves the neurological outcome in glutaric aciduria type I.

OBJECTIVE: To evaluate the effect of treatment according to current evidence-based recommendations on the neurological outcome of patients with glutaric aciduria type I (GA-I). METHODS: Fifty-two patients identified by newborn screening (NBS) in Germany from 1999 to 2009 were followed prospectively. Neurological outcome was assessed by the occurrence of an acute encephalopathic crisis and the severity of a movement disorder (MD) with predominant dystonia superimposing on axial hypotonia. Outcome was evaluated in relation to therapy and therapy-independent parameters. RESULTS: Outcome was best in GA-I patients who were treated in full accordance with treatment recommendations (n=37; 5% MD). Deviations from recommended basic metabolic treatment (low-lysine diet, carnitine) resulted in an intermediate outcome (n=9; 44% MD), whereas disregard of emergency treatment recommendations was associated with a poor outcome (n=6; 100% MD). Treatment regimens deviating from recommendations significantly increased the risk for MD (odds ratio [OR], 35; 95% confidence interval [CI], 5.88-208.39) and acute encephalopathic crises (OR, 51.32; 95% CI, 2.65-993.49). Supervision by a metabolic center improved the outcome (18% vs 57% MD; OR, 6.17; 95% CI, 1.15-33.11), whereas migrational background and biochemical phenotype (high versus low excretor status) had no significant effect. INTERPRETATION: Follow-up of neonatally diagnosed patients with GA-I in Germany clearly demonstrates that the inclusion of this rare disease in the NBS disease panel has significantly improved the neurological outcome of affected individuals. The establishment of and adherence to evidence-based treatment recommendations, and supervision by experienced metabolic centers helps to minimize the number of patients who do not benefit from NBS.

Mouse model of encephalopathy and novel treatment strategies with substrate competition in glutaric aciduria type I.

Glutaric aciduria type I (GA-1) results from an inherited defect in a common step of lysine, hydroxylysine and tryptophan metabolism. This defect is associated with an age-dependent susceptibility to encephalopathy commonly preceded by non-specific childhood illnesses or fasting. The brain injury that develops with encephalopathic crisis in GA-1 is anatomically and symptomatically similar to Huntington's disease, affecting the striatum. The mechanism of injury remains poorly understood. Recently, an animal model of GA-1 encephalopathy was developed by providing GA-1 mice with added dietary lysine. This model shows age-dependent susceptibility similar to the human disease. Enhanced lysine accumulation and utilization in the immature brain correlates with increased glutaric acid levels and age-dependent susceptibility. Neurotransmitter and Krebs cycle intermediate depletion in this model represent novel findings toward uncovering the mechanism of neuronal injury. Additionally this mouse model is responsive to glucose analogous to human GA-1 and provides insight toward the mechanism of this effect. Together these findings led to a new treatment strategy of competing with brain lysine uptake that shows promising results. This research serves as a model for understanding blood brain barrier amino acid transport at critical stages of development and may help advance understanding of brain injury and development of treatments in other IEMs including urea cycle disorders.

Diagnosis, treatment, and long-term outcomes of late-onset (type III) multiple acyl-CoA dehydrogenase deficiency.

We report 4 children with late-onset (type III) multiple acyl-CoA dehydrogenase deficiency, also known as glutaric aciduria type II, which is an autosomal recessive disorder of fatty acid and amino acid metabolism. The underlying deficiency is in the electron transfer flavoprotein or electron flavoprotein dehydrogenase. Clinical presentations include fatal acute neonatal metabolic encephalopathies with/without organ system anomalies (types I and II) and late-onset acute metabolic crises, myopathy, or neurodevelopmental delays (type III). Two patients were identified in childhood following a metabolic crisis and/or neurodevelopmental delay, and 2 were identified by newborn metabolic screening. Our cases will illustrate the difficulty in making a biochemical diagnosis of late-onset (type III) multiple acyl-CoA dehydrogenase deficiency from plasma acylcarnitines and urine organic acids in both symptomatic and asymptomatic children. However, they emphasize the need for timely diagnosis to urgently implement prophylactic treatment for life-threatening metabolic crises with low protein/fat diets supplemented with riboflavin and carnitine.

Glutaric aciduria type II [corrected] and brain tumors: a case report and review of the literature.

Heritable diseases associated with childhood tumors are sometimes defined as a probable etiologic factor or a coincidence. First of all, we must know the actual number of patients. Herein a case with medulloblastoma associated with glutaric aciduria type II [corrected] is reported for this purpose. A 5-year-old boy was admitted with nausea, vomiting, and lethargy. In medical history, consanguinity and siblings with mental-motor retardation and epilepsy are remarkable. Growth retardation, macrocephaly, lethargy, tremor, bilateral nistagmus, and papilledema were prominent features in physical examination. Noncontrast computed tomography of the brain showed a hyper dense mass in the cerebellar vermis. Gross total resection was made and the histopathology of the tumor was medulloblastoma. Besides medical history and physical findings, radiologic white matter changes in the subcortical, periventricular regions, bilateral basal ganglia, and caudate nuclei in magnetic resonance images other than tumor led us to investigate the child for glutaric aciduria type II [corrected]. The level of the 2-OH glutaric acid was determined as being 12-fold high in the urine. Chemo-radiotherapy was performed after surgery. Our case was the third patient with medulloblastoma in the literature and is still alive with no evidence of the disease 19 months after the initial diagnosis.

Newborn screening for glutaric aciduria type I in Victoria: treatment and outcome.

Between October 2001 and September 2007, a total number of 391,651 neonates were screened in Victoria using Tandem Mass Spectrometry and 6 newborns were diagnosed as having GA I, giving an incidence of 1:65,275 (CI: 1:29,988=1:177,861). Another patient was diagnosed through cascade screening of children born before the implementation of the expanded newborn screening program. Patients were treated by mild protein restriction (2-2.5 g/kg/day) and carnitine supplementation when well, focussing on the aggressive management of intercurrent illnesses (temporary cessation of protein intake, increase in calorie intake, IV carnitine, aggressive anti febrile and anti infectious treatment), including prophylactic admissions to hospital. Overall, our patients had 35 admissions to hospital, of which 15 were in the first year of life. None had a post infectious dystonic syndrome. Neuropsychological examinations revealed normal to high cognitive and gross motor function in all patients but one, with some deficiencies in fine motor activities and different levels of speech abnormalities in all patients. Since therapeutic approaches for GA I, although not uniform, are well established and have been documented to be effective, newborn screening for this disorder should prove justified. A therapeutic approach of dietary modification, IV carnitine and aggressive treatment of intercurrent illness seems to prevent the severe neurological complications of GA I. More in-depth consideration of speech and language function is necessary to document specific deficits in children with GA I and plan proactive interventions.

Glutaric aciduria type II and narcolepsy in pregnancy.

BACKGROUND: Glutaric aciduria type II is a rare disorder affecting the metabolism of fatty acid oxidation and several mitochondrial dehydrogenase enzymes. Narcolepsy and cataplexy is a disorder affecting sleep cycles and rapid eye movement activity. There is little information on outcome or management for either disorder in pregnancy. CASE: This is a case of a 16-year-old with glutaric aciduria type II and narcolepsy with cataplexy, treated with L-carnitine, riboflavin, fluoxetine, and modafinil during pregnancy. Intrapartum management included intravenous carnitine administration, and the patient underwent cesarean delivery at term without complication. CONCLUSION: This inborn error of metabolism and sleep disorder can be effectively treated during pregnancy with nutritional supplementation and stimulants. Because of the risk of cataplexy during labor, cesarean delivery is recommended to minimize the patient's risk.