Safety and recommendations for vaccinations of children with inborn errors of metabolism.

Inborn errors of metabolism (IEM) are genetic disorders due to a defective metabolic pathway. The incidence of each disorder is variable and depends on the respective population. Some disorders such as urea cycle disorders (UCD) and organic acidurias, pose a high risk for a metabolic crisis culminating in a life-threatening event, especially during infections; thus, vaccines may play a crucial role in prevention. However, there are different triggers for decompensations including the notion that vaccines themselves can activate fever and malaise. Additionally, many of the IEM include immunodeficiency, placing the patients at an increased risk for infectious diseases and possibly a weaker response to immunizations. Since metabolic crises and vaccine regimens intersect in the first years of life, the question whether to vaccinate the child occupies parents and medical staff. Many metabolic experts hesitate to vaccinate IEM patients, disregarding the higher risk from the direct infections. In this paper we summarize the published data regarding the safety and recommendations for vaccinations in IEM patients, with reference to the risk for decompensations and to the immunogenic component.

Pyridoxine dependent epilepsy: Is late onset a predictor for favorable outcome?

AIM: In pyridoxine dependent epilepsy (PDE), patients usually present with neonatal seizures. A small subgroup is characterized by late-onset beyond 2 months of age. We aim to analyze the observation of relatively good cognitive outcome in this subgroup of late-onset PDE patients. METHODS: We retrospectively analyzed data from four metabolically and genetically confirmed late-onset patients with PDE due to antiquitin (ALDH7A1) deficiency. Data were analyzed regarding ALDH7A1 mutations, alpha-Aminoadipic semialdehyde (α-AASA) and pipecolic acid (PA) levels, medication during pregnancy, delivery, treatment delay, amount of seizures, pyridoxine dose, adjuvant therapy and findings on brain MRI. RESULTS: Results showed that three patients had relatively good outcome (IQ 80-97), while one patient did not undergo formal testing and was considered mildly delayed. We were unable to find a clear association between the above-mentioned variables and cognitive outcome, although a less severe genotype may be present in three patients, and maternal medication could be accountable for better outcome in two patients. INTERPRETATION: We suggest that favorable outcome in late onset PDE might be explained by a combination of factors. A yet unknown protective factor, different genetic variations, functional variation and secondarily variation in treatment regimens and absence of neonatal seizure induced brain damage.

Epileptic phenotypes, electroclinical features and clinical characteristics in 17 children with anti-NMDAR encephalitis.

BACKGROUND: Anti-N-methyl d-aspartate receptor (NMDAR) encephalitis is a rare disorder characterized by seizures, neuropsychiatric symptoms, dyskinesia and autonomic instability. OBJECTIVE: Aim of the present study was to evaluate the seizure phenotypes and electroencephalogram (EEG) features in children with anti-NMDAR encephalitis. METHODS: Seizure types, electroclinical features and clinical characteristics of 17 children with anti-NMDAR encephalitis were analysed in a retrospective case series from nine centres in Europe. RESULTS: Nearly half (8/17) of the children presented with psychiatric symptoms, whereas in 4/17 patients seizures were the first symptom and in 5/17 both symptoms occurred at the same time. During the following course seizures were reported in 16/17 children. The first EEG detected generalized slowing in 11/17 patients, focal slowing in 3/17 and normal background activity in only 3/17 children. The extreme delta brush (EDB) pattern was detected in 9/17 (53%) patients. CONCLUSION: In addition to psychiatric symptoms, children with anti-NMDAR encephalitis often show generalized slowing in EEG with or without seizures at initial presentation. EDB is present in half of all children and is potentially a helpful tool for early detection of this immune-mediated disease.

Clinical onset and course, response to treatment and outcome in 24 patients with the cblE or cblG remethylation defect complemented by genetic and in vitro enzyme study data.

BACKGROUND: The cobalamin E (cblE) (MTRR, methionine synthase reductase) and cobalamin G (cblG) (MTR, methionine synthase) defects are rare inborn errors of cobalamin metabolism leading to impairment of the remethylation of homocysteine to methionine. METHODS: Information on clinical and laboratory data at initial full assessment and during the course of the disease, treatment, outcome and quality of life was obtained in a survey-based, retrospective study from physicians caring for patients with the CblE or CblG defect. In addition, data on enzyme studies in cultured skin fibroblasts and mutations in the MTRR and MTR gene were analysed. RESULTS: In 11 cblE and 13 cblG patients, failure to thrive, feeding problems, delayed milestones, muscular hypotonia, cognitive impairment and macrocytic anaemia were the most frequent symptoms. Delay in diagnosis depended on age at first symptom and clinical pattern at presentation and correlated significantly with impaired communication abilities at follow-up. Eighteen/22 patients presented with brain atrophy or white matter disease. Biochemical response to treatment with variable combinations of betaine, cobalamin, folate was significant. The overall course was considered improving (n = 8) or stable (n = 15) in 96% of patients, however the average number of CNS symptoms per patient increased significantly over time and 16 of 23 patients were classified as developmentally delayed or severely handicapped. In vitro enzyme analysis data showed no correlation with outcome. Predominantly private mutations were detected and no genotype- phenotype correlations evident. CONCLUSIONS: The majority of patients with the cblE and cblG defect show limited clinical response to treatment and have neurocognitive impairment.

Phenotype determining alleles in GM1 gangliosidosis patients bearing novel GLB1 mutations.

GM1 gangliosidosis manifests with progressive psychomotor deterioration and dysostosis of infantile, juvenile, or adult onset, caused by alterations in the structural gene coding for lysosomal acid beta-galactosidase (GLB1). In addition, allelic variants of this gene can result in Morquio B disease (MBD), a phenotype with dysostosis multiplex and entire lack of neurologic involvement. More than 100 sequence alterations in the GLB1 gene have been identified so far, but only few could be proven to be predictive for one of the GM1 gangliosidosis subtypes or MBD. We performed genotype analyses in 16 GM1 gangliosidosis patients of all phenotypes and detected 28 different genetic lesions. Among these, p.I55FfsX16, p.W65X, p.F107L, p.H112P, p.C127Y, p.W161X, p.I181K, p.C230R, p.W273X, p.R299VfsX5, p.A301V, p.F357L, p.K359KfsX23, p.L389P, p.D448V, p.D448GfsX8, and the intronic mutation IVS6-8A>G have not been published so far. Due to their occurrence in homozygous patients, four mutations could be correlated to a distinct GM1 gangliosidosis phenotype. Furthermore, the missense mutations from heteroallelic patients and three artificial nonsense mutations were characterized by overexpression in COS-1 cells, and the subcellular localization of the mutant proteins in fibroblasts was assessed. The phenotype specificity of 10 alleles can be proposed on the basis of our results and previous data.

Epilepsy in patients with propionic acidemia.

Propionic acidemia (PA) is an autosomal recessively inherited defect of propionyl-CoA carboxylase with an incidence of approximately 1:50 000. There are few reports on the occurrence of EEG findings and development of epilepsy in patients with PA. Retrospectively, the data of 17 patients with PA from one Italian and four Austrian centers were evaluated concerning EEG findings and the development of epilepsy. Nine patients showed a disturbance of background activity, as well as epileptiform discharges. All nine patients with pathological EEG discharges developed seizures compatible with the definition of symptomatic epilepsy. Five of these nine patients showed fever induced seizures at the beginning. Two of them suffered from symptomatic absence epilepsy. Six of the nine patients with seizures were treated with antiepileptic drugs (AED), which were tolerated without side-effects. Four patients showed photosensitivity, which so far has never been reported in PA. We hypothesize that patients with PA are prone to cortical dysfunction caused by one or several pathological metabolites - leading to changes in background and epileptiform activity with a high manifestation rate of clinical seizures.

Malignant stroke in an adolescent with a homozygous MTHFR 677CT mutation and intake of hormonal contraceptives.

UNLABELLED: Severe stroke in children and adolescents with its devastating long term consequences remains a rare disorder with many open questions. Beside the well known risk factors such as infection or congenital and acquired heart disease, coagulation disorders have to be considered in the differential work up of the underlying aetiology. Here we report the case of an adolescent with a homozygote MTHFR 677CT mutation suffering a malignant stroke shortly after the start of oral contraceptives. CONCLUSION: Since prevention seems easily feasible, general screening for MTHFR mutations might be worthwhile in women before starting oral contraceptives.

Treatment recommendations in long-chain fatty acid oxidation defects: consensus from a workshop.

Published data on treatment of fatty acid oxidation defects are scarce. Treatment recommendations have been developed on the basis of observations in 75 patients with long-chain fatty acid oxidation defects from 18 metabolic centres in Central Europe. Recommendations are based on expert practice and are suggested to be the basis for further multicentre prospective studies and the development of approved treatment guidelines. Considering that disease complications and prognosis differ between different disorders of long-chain fatty acid oxidation and also depend on the severity of the underlying enzyme deficiency, treatment recommendations have to be disease-specific and depend on individual disease severity. Disorders of the mitochondrial trifunctional protein are associated with the most severe clinical picture and require a strict fat-reduced and fat-modified (medium-chain triglyceride-supplemented) diet. Many patients still suffer acute life-threatening events or long-term neuropathic symptoms despite adequate treatment, and newborn screening has not significantly changed the prognosis for these severe phenotypes. Very long-chain acyl-CoA dehydrogenase deficiency recognized in neonatal screening, in contrast, frequently has a less severe disease course and dietary restrictions in many patients may be loosened. On the basis of the collected data, recommendations are given with regard to the fat and carbohydrate content of the diet, the maximal length of fasting periods and the use of l-carnitine in long-chain fatty acid oxidation defects.

Management and outcome in 75 individuals with long-chain fatty acid oxidation defects: results from a workshop.

At present, long-chain fatty acid oxidation (FAO) defects are diagnosed in a number of countries by newborn screening using tandem mass spectrometry. In the majority of cases, affected newborns are asymptomatic at time of diagnosis and acute clinical presentations can be avoided by early preventive measures. Because evidence-based studies on management of long-chain FAO defects are lacking, we carried out a retrospective analysis of 75 patients from 18 metabolic centres in Germany, Switzerland, Austria and the Netherlands with special regard to treatment and disease outcome. Dietary treatment is effective in many patients and can prevent acute metabolic derangements and prevent or reverse severe long-term complications such as cardiomyopathy. However, 38% of patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency had intermittent muscle weakness and pain despite adhering to therapy. Seventy-six per cent of patients with disorders of the mitochondrial trifunctional protein (TFP)-complex including long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, had long-term myopathic symptoms. Of these, 21% had irreversible peripheral neuropathy and 43% had retinopathy. The main principle of treatment was a fat-reduced and fat-modified diet. Fat restriction differed among patients with different enzyme defects and was strictest in disorders of the TFP-complex. Patients with a medium-chain fat-based diet received supplementation of essential long-chain fatty acids. l-Carnitine was supplemented in about half of the patients, but in none of the patients with VLCAD deficiency identified by newborn screening. In summary, in this cohort the treatment regimen was adapted to the severity of the underlying enzyme defect and thus differed among the group of long-chain FAO defects.

Two novel mutations in the GDAP1 and PRX genes in early onset Charcot-Marie-Tooth syndrome.

Autosomal recessive Charcot-Marie-Tooth syndrome (AR-CMT) is often characterised by an infantile disease onset and a severe phenotype. Mutations in the ganglioside-induced differentiation-associated protein 1 (GDAP1) gene are thought to be a common cause of AR-CMT. Mutations in the periaxin (PRX) gene are rare. They are associated with severe demyelination of the peripheral nerves and sometimes lead to prominent sensory disturbances. To evaluate the frequency of GDAP1 and PRX mutations in early onset CMT, we examined seven AR-CMT families and 12 sporadic CMT patients, all presenting with progressive distal muscle weakness and wasting. In one family also prominent sensory abnormalities and sensory ataxia were apparent from early childhood. In three families we detected four GDAP1 mutations (L58LfsX4, R191X, L239F and P153L), one of which is novel and is predicted to cause a loss of protein function. In one additional family with prominent sensory abnormalities a novel homozygous PRX mutation was found (A700PfsX17). No mutations were identified in 12 sporadic cases. This study suggests that mutations in the GDAP1 gene are a common cause of early-onset AR-CMT. In patients with early-onset demyelinating AR-CMT and severe sensory loss PRX is one of the genes to be tested.

Mental retardation in a girl with a subtelomeric deletion on chromosome 20q and complete deletion of the myelin transcription factor 1 gene (MYT1).

A great number of syndromes and inborn errors of metabolism associated with impaired development have been observed, but the aetiology of mental retardation remains unclear in a considerable proportion of cases. Here, we present the clinical and molecular data from a patient with a new de novo subtelomeric deletion on chromosome 20 [46,XX.ish del(20)(qter-)]. For further refinement, bacterial artificial chromosome clones are used. The deletion spans exactly two genes called MYT1 and PCMTD2. Both genes play an important role in myelination and regulating neural differentiation. Loss of these two genes seems to be responsible for the severe mental retardation and mild facial dysmorphic features in our young patient. It might show the phenotypic picture of this specified deletion.

GJA12 mutations are a rare cause of Pelizaeus-Merzbacher-like disease.

BACKGROUND: Pelizaeus-Merzbacher-like disease (PMLD) is a genetically heterogeneous disorder within the group of hypomyelinating leukoencephalopathies. Mutations of the gap junction protein alpha 12 (GJA12) gene are known to cause one autosomal recessive PMLD form. Few patients with GJA12 mutated PMLD have been reported, and to date, the frequency as well as the genotypic and phenotypic spectrum of GJA12 related PMLD is unclear. METHODS: We report mutation analysis of the GJA12 gene in a clinical and radiologic well-characterized multiethnic cohort of 193 patients with PMLD from 182 families. RESULTS AND CONCLUSIONS: Only 16 patients (8.3%) from 14 families (7.7%) carry GJA12 mutations including five families where we detected only one mutated allele. Among those, we identified 11 novel alterations. Thus, GJA12 mutations are a rather rare cause for Pelizaeus-Merzbacher-like disease. The clinical phenotype of patients with a GJA12 mutation was evaluated and is overall comparable to the clinical features seen in mild forms of proteolipid protein 1 (PLP1) related disorder but with better cognition and earlier signs of axonal degeneration.

Mutation and phenotypic spectrum in patients with cardio-facio-cutaneous and Costello syndrome.

Cardio-facio-cutaneous (CFC) and Costello syndrome (CS) are congenital disorders with a significant clinical overlap. The recent discovery of heterozygous mutations in genes encoding components of the RAS-RAF-MAPK pathway in both CFC and CS suggested a similar underlying pathogenesis of these two disorders. While CFC is heterogeneous with mutations in BRAF, MAP2K1, MAP2K2 and KRAS, HRAS alterations are almost exclusively associated with CS. We carried out a comprehensive mutation analysis in 51 CFC-affected patients and 31 individuals with CS. Twelve different BRAF alterations were found in twenty-four patients with CFC (47.0%), two MAP2K1 mutations in five (9.8%) and two MAP2K2 sequence variations in three CFC-affected individuals (5.9%), whereas three patients had a KRAS alteration (5.9%). We identified four different missense mutations of HRAS in twenty-eight cases with CS (90.3%), while KRAS mutations were detected in two infants with a phenotype meeting criteria for CS (6.5%). In 14 informative families, we traced the parental origin of HRAS alterations and demonstrated inheritance of the mutated allele exclusively from the father, further confirming a paternal bias in the parental origin of HRAS mutations in CS. Careful clinical evaluation of patients with BRAF and MAP2K1/2 alterations revealed the presence of slight phenotypic differences regarding craniofacial features in MAP2K1- and MAP2K2-mutation positive individuals, suggesting possible genotype-phenotype correlations.

Pyridoxine-dependent epilepsy: normal outcome in a patient with late diagnosis after prolonged status epilepticus causing cortical blindness.

We report on a male proband with pyridoxine-dependent epilepsy (PDE) and neonatal seizure onset. At the age of 31 months, a prolonged status epilepticus led to severe neurological regression with cortical blindness, loss of speech and muscular hypotonia with slow recovery over the following 3 months. At 33 months of age pyridoxine therapy was initiated with excellent response and the boy remained seizure-free on pyridoxine monotherapy, except for two occasions with seizure recurrence 10 days after accidental pyridoxine withdrawal. alpha-aminoadipic semialdehyde dehydrogenase (antiquitin) deficiency was indicated by elevated pipecolic acid concentrations in plasma and alpha-aminoadipic semialdehyde excretion in urine. Molecular analysis of the antiquitin gene revealed a novel missense mutation c.57insA, while the mutation of the other allele remained unidentified so far. Despite the delay in diagnosis and prolonged status epilepticus, neuropsychological evaluations at the ages of 11 and 18 years demonstrated full-scale IQ of 93 and 92, respectively, with better verbal IQ (103 and 101) than performance IQ (85 and 82).

Brainstem disconnection: case report and review of the literature.

We report a neonate with brainstem disconnection. Only five similar cases have previously been described, the longest survival was 7 weeks. The newborn exhibited muscular hypertonia, absent suction, insufficient breathing, and seizures. Magnetic resonance imaging showed a disconnection between the upper pons and the medulla oblongata and cerebellar hypoplasia. The basilar artery was not visible. These neuroimaging findings are clearly different from other midbrain or hindbrain malformations with cerebellar hypoplasia. This pattern and a previously reported autopsy point to a malformation, not a disruption.

Copper concentration of liver tissue under long-term copper-histidine therapy in a patient with Menkes disease.

Copper-histidine is the treatment of choice in Menkes disease but bears the potential risk of copper overload and induced liver cirrhosis. We report normal copper concentrations of liver tissue over an 8-year treatment period with copper-histidine.

Pipecolic acid concentrations in brain tissue of nutritionally pyridoxine-deficient rats.

Elevated concentrations of pipecolic acid have been reported in plasma and CSF of patients with pyridoxine-dependent epilepsy, but its molecular background is unclear. To investigate any further association of pyridoxine and pipecolic acid metabolism, we have performed an animal trial and have measured the concentration of pipecolic acid in brain tissue of rats with nutritional pyridoxine deficiency and in control littermates. Concentrations of pyridoxal phosphate were significantly reduced in brain tissue of pyridoxine-deficient rats (p < 0.001), while concentrations of pipecolic acid were not significantly different from the normally nourished control group (p = 0.3). These data indicate that a direct association of pyridoxine and pipecolic acid metabolism is unlikely. We therefore assume that the characteristic elevation of pipecolic acid in pyridoxine-dependent epilepsy could rather be a secondary phenomenon with the primary defect of pyridoxine-dependent epilepsy being located outside the pipecolic acid pathway.

Pipecolic acid as a diagnostic marker of pyridoxine-dependent epilepsy.

Pyridoxine-dependent epilepsy, although described some decades ago, may still be an underdiagnosed disorder. We have recently described isolated pipecolic acid elevations in the plasma and/or CSF of three patients with pyridoxine-dependent epilepsy with an intriguing inverse correlation to the oral intake of pyridoxine. We have now confirmed these findings in a further 6 unrelated patients with pyridoxine-dependent epilepsy. Pipecolic acid in plasma was 4.3- to 15.3 fold elevated compared to the upper normal range before pyridoxine and remained in the mildly elevated range while on pyridoxine. Pipecolic acid was even more markedly elevated in CSF. The extent of pipecolic acid elevation in CSF exceeded that of plasma by a factor of 2.2 to 4.8. This clearly discriminates pyridoxine-dependent epilepsy from other possible defects with elevated pipecolic acid. Determination of pipecolic acid in plasma and/or CSF should be included in the diagnostic work-up of patients with therapy-resistant seizures. It will in addition prevent patients with pyridoxine-dependent epilepsy from experiencing potentially dangerous pyridoxine-withdrawal, which until now has been necessary to prove the diagnosis.