Treatable inborn errors of metabolism causing neurological symptoms in adults.

BACKGROUND: The identification of inborn errors of metabolism (IEM) in adults presenting with a wide range of neurological symptoms is a relatively new field in medicine. We sought to identify which treatable IEM have been diagnosed for the first time in adults and generate a protocol for metabolic screening targeting those treatable disorders. METHODS: Medline/Pubmed searches of English language literature limited to the adult age group were performed. Diseases identified through this search were then compared to previously published lists of treatable IEM in both adults and children. RESULTS: 85% of the treatable conditions known to cause global developmental delay or intellectual disability in children had reports where the diagnosis of that IEM was made in one or more adult patients with neurological symptoms. Screening tests in blood, urine, CSF and MRI can detect most of these treatable conditions but the diagnostic accuracy of these screening tests in adults is not clear. CONCLUSION: Treatable IEM need to be considered in the differential diagnosis of neurological symptoms in patients of any age.

Long term follow-up of the dietary intake in propionic acidemia.

Long-term dietary management of Propionic acidemia (PA) includes natural protein restriction, and supplementation with medical formula enriched with leucine (Leu) and free of valine (Val), isoleucine (Ileu), methionine (Met), and threonine (Thr). As PA medical formulas have high leucine content, concerns started to arise regarding potential long-term health risks of unbalanced leucine intake. PA patients have chronically low plasma levels of Ile and Val, which led to the paradoxical need to supplement with propiogenic single amino acids (AAs). Our report takes a retrospective look at the long-term dietary management of four patients and its reflection on their plasma amino acids. The patients' total protein intake was above the recommended dietary allowance (RDA) and had a high Leu/Val and Leu/Ile intake ratios in diet. Despite adequate total protein intake, patients had chronically low plasma Ile and Val and a high plasma Leu/Val and Leu/Ile ratios, which could be attributed to high Leu intake. We conclude that the best approach to PA dietary management is to only use medical formula with patients not meeting their RDA through natural protein, and to monitor plasma amino acids levels closely.

Intracranial calcification after cord blood neonatal transplantation for krabbe disease.

Infantile-onset Krabbe disease results from a deficiency of the lysosomal enzyme galactocerebrosidase and leads to death from profound central and peripheral demyelination. Neonatal hematopoietic cell transplantation may result in near-normal cognitive development and partial rescue of gross motor development. The long-term course of the disorder for treated patients seems to involve slowly progressive neurological impairment. We describe the detailed 3-year outcomes of this experimental procedure using umbilical cord blood in a prenatally-diagnosed newborn with Krabbe disease. Substantial perivascular calcifications and atrophy of the white matter developed in the first year post-transplantation. Despite persistent neuroradiological and electrophysiological evidence of leukodystrophy, at age 3 years she has had only mildly impaired non-motor development and moderately impaired motor skills. The cause of these severe white matter changes may have been due to ongoing Krabbe disease or to effects of the chemotherapy regimen or to an interaction of these factors. Extended long-term follow-up of children neonatally transplanted for Krabbe disease is needed before the full utility and limitations of neonatal transplantation can be determined.

Guanidino compounds in guanidinoacetate methyltransferase deficiency, a new inborn error of creatine synthesis.

The first inborn error of creatine metabolism (guanidinoacetate methyltransferase [GAMT] deficiency) has recently been recognized in an infant with progressive extrapyramidal movement disorder. The diagnosis was established by creatine deficiency in the brain as detected by in vivo magnetic resonance spectroscopy and by defective GAMT activity and two mutant GAMT alleles in a liver biopsy. Here, we describe characteristic guanidino-compound patterns in body fluids of this index patient with GAMT deficiency. Concentrations of guanidino compounds (creatine and guanidinoacetate) and creatinine were determined by cation-exchange chromatography and by color reaction with picric acid, respectively, in urine, plasma, and cerebrospinal fluid (CSF). Creatine concentrations were low in plasma, CSF, and urine while guanidinoacetate concentrations were markedly elevated. Daily urinary creatinine excretion was low, whereas creatinine concentrations in random urine samples were not always discriminative. Guanidino compound to creatinine ratios were not informative, as low creatinine concentrations resulted in high values for all determined compounds. During a 22-month period of oral treatment with creatine-monohydrate, plasma and urinary creatine concentrations increased to levels high above the normal range, and daily urinary creatinine excretion-proportional to total body creatine-became normalized. Guanidinoacetate concentrations remained elevated even during additional substitution of ornithine, which inhibits guanidinoacetate synthesis in vitro. The results indicate that GAMT deficiency can be recognized noninvasively by determination of guanidino compounds (creatine and guanidinoacetate) in body fluids. A deficiency of creatine, but not an accumulation of guanidinoacetate, can be corrected by treatment with oral creatine substitution.

Guanidinoacetate methyltransferase deficiency: a newly recognized inborn error of creatine biosynthesis.

In an infant with progressive, severe extrapyramidal movement disorder and extremely. low urinary creatinine excretion, in vivo proton magnetic resonance spectroscopy of the brain showed a depletion of creatine and an accumulation of guanidinoacetate, the immediate precursor of creatine. The suggested defect in creatine biosynthesis at the level of guanidinoacetate methyltransferase was confirmed by the demonstration of defective activity of this enzyme in liver tissue and by identification of the underlying genetic defect. Creatine substitution by means of oral creatine monohydrate at high dosage (4-8 g per day) resulted in a striking improvement of the extrapyramidal movement disorder, normalisation of abnormal slow background activity in the EEG, and disappearance of bilateral abnormal signal intensities in the globus pallidus. The low urinary creatine excretion normalized and brain creatine and creatine phosphate, as measured by in vivo magnetic resonance spectroscopy, increased significantly. Guanidinoacetate methyltransferase deficiency is a new, treatable inborn error of metabolism. Screening methods and non-invasive diagnosis of the enzyme defect are needed for the early detection and treatment of patients with this effect.

[Strategies for the diagnosis of lysosomal storage diseases: symptoms, methods and samples]. / Strategien zur Diagnose lysosomaler Speichererkrankungen: Symptome, Methoden, Untersuchungsmaterial.

Lysosomal diseases are a group of about 30 genetic defects with a total incidence of 3 to 4 cases/10,000 newborns. Their clinical appearance is very heterogeneous and comprises infantile, as well as juvenile or adult forms. Our concept for their diagnosis has now been in use for eight years and entails the following strategy: The three main symptom groups coarse facial features, visceromegaly and/or psychomotor retardation should be examined for their typical expression and for the occurrence of specific "key symptoms". Thereafter, biochemical analysis of urine for oligosaccharides, mucopolysaccharides and in some cases, of sphingolipids or direct enzyme assays in serum, peripheral leucocytes or skin fibroblasts are performed. The selection of appropriate methods is usually the domain of the biochemist and greatly depends on the available samples and the quality of clinical information. The diagnostic value and the limitations of methods and samples are discussed in detail. Finally, evidence of defects in the expression of relevant gene products, such as enzymes, activator proteins or transport proteins can be obtained and used for genetic counselling and/or for prenatal diagnosis in chorionic villi or cultured amniotic fluid cells. Our results confirm the data on the high incidence of mucopolysaccharidoses I and III A. In addition, a comparatively high number of otherwise rare diseases, such as fucosidosis or sialic acid storage disease was found. Among the group of sphingolipidoses, special attention should be paid to juvenile or adult forms.

[Peroxisomal neurologic diseases and Refsum disease: very long chain fatty acids and phytanic acid as diagnostic markers]. / Peroxisomale neurologische Erkrankungen und M. Refsum: Uberlangkettige Fettsäuren und Phytansäure als diagnostische Marker.

Peroxisomal disorders are genetic metabolic diseases with generalized, multiple, or single functional disturbances of the peroxisome. According to the extent of the functional disturbances 3 groups of diseases can be differentiated: disorders with generalized loss of peroxisomal functions (Zellweger syndrome, ZS; neonatal adrenoleukodystrophy, NALD; infantile Refsum's disease), disorders with multiple enzymatic defects (e.g. rhizomelic chondrodysplasia punctata), and disorders with a single enzymatic defect in the peroxisome, the most important being adrenoleukodystrophy/adrenomyeloneuropathy (ALD/AMN). Adult Refsum's disease, a genetic neurological disorder with phytanic acid accumulation, is due to a mitochondrial enzyme deficiency, but is often considered together with peroxisomal diseases because of phytanic acid (PHYT) accumulation in most peroxisomal diseases. The main clinical and pathological criteria of the major disorders and the biochemical parameters of their differentiation are presented. Elevated levels of very long chain fatty acids (VLCFA) and/or PHYT are the primary diagnostic markers for all peroxisomal disorders and adult Refsum's disease, respectively. Our investigations disclosed 30 ALD/AMN hemizygotes, 16 ALD/AMN heterozygotes, 8 cases of ZS/NALD and 7 patients with adult Refsum's disease. In addition, 15 cases of peroxisomal disorders were confirmed by biochemical investigations in autopsy material. With regard to peroxisomal disorders, therapeutic concepts exist only for ALD/AMN: corticosteroid substitution for adrenal insufficiency, dietary treatment, and bone marrow transplantation (BMT). Adult Refsum's disease can be treated successfully by dietary therapy. In case of dietary treatment and BMT, assay of VLCFA and/or PHYT is important for the biochemical evaluation of these therapies.

[Pregnancy and neonatal screening in Austria]. / Schwangeren- und Neugeborenenscreening in Osterreich.

In Austria neonatal mortality remains higher than in comparable industrial countries. For this reason the Austrian Academy of Sciences published a study (Köck Ch., Kytir J., Münz R.: Risiko Süglingstod, Plädoyer für eine gesundheitspolitische Reform, Franz Deuticke, Wien 1988) comprising a historical review, an analysis of the present situation and proposals for improvement of the public health care programmes for pregnant women, mothers and neonates. Furthermore, current Austrian health policy is criticized on the basis of two concrete examples (the neonatal mass screening programme for inherited metabolic diseases and compulsory ultrasound screening in pregnancy). However, the authors reach their conclusions from incompletely cited and subjectively (partly falsely) interpreted scientific literature, with misleading consequences. Reviewing the literature in a more complete way, we wish to point out the superficial character of the research carried out by the authors. This kind of work should not serve as a basis for decisions in public health policy.

[Zellweger syndrome, neonatal adrenoleukodystrophy or infantile Refsum's disease in a case with generalized peroxisome defect?]. / Zellweger-Syndrom, neonatale Adrenoleukodystrophie oder infantile Refsumsche Erkrankung bei einem Fall mit generalisiertem Peroxisomendefekt?

An eleven month-old boy presented clinically with craniofacial dysmorphia, severe psychomotor retardation, neurological deterioration, no response to visual and acoustic stimuli, failure to thrive, hepatomegaly and adrenal insufficiency. Specific biochemical markers for a peroxisomal deficiency disorder (Zellweger's syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease) revealed pathological results for very long chain fatty acids, phytanic acid, pristanic acid, plasmalogen biosynthesis and catalase, thus confirming the clinical diagnosis. Comparison of clinical and biochemical findings in the patient with the characteristics of the three peroxisomal deficiency disorders showed overlapping with each of these disorders, which corresponds to the current view that these three peroxisomal disorders differ only with respect to onset and severity of the clinical manifestations, but not with regard to the biochemical defects.

Creatine replacement therapy in guanidinoacetate methyltransferase deficiency, a novel inborn error of metabolism.

BACKGROUND: The creatine/creatine-phosphate system is essential for the storage and transmission of phosphate-bound energy in muscle and brain. In infants, inefficiency or failure of this metabolic pathway can impair the development of motor control and mentation. METHODS: We studied and treated an infant with extrapyramidal signs who was shown--by assay for urinary creatinine and by analysis of brain metabolites with use of nuclear magnetic resonance spectra--to have depletion of body and brain creatine, due to inborn deficiency of guanidinoacetate methyltransferase (GAMT). FINDINGS: Long-term oral administration of creatine-monohydrate (4-8 g per day) to this index patient resulted in substantial clinical improvement, disappearance of magnetic resonance (MRI) signal abnormalities in the globus pallidus, and normalisation of slow background activity on the electroencephalogram (EEG). During the 25-month treatment period, both brain and total body creatine concentrations became normal. INTERPRETATION: Oral creatine replacement has proved to be effective in one child with an inborn error of GAMT. It may well be effective in the treatment of other disorders of creatine synthesis.

[Congenital metabolic diseases as a cause of acute illnesses in the neonatal period]. / Angeborene Stoffwechselerkrankungen als Ursache akuter Krankheitsbilder in der Neugeborenenperiode.

Inborn errors of metabolism occurring in the neonatal period both comprise diseases with clinical onset immediately after birth and diseases with clinical onset after a symptom free interval. Organ damage caused by inherited metabolic diseases can occur already in utero or--depending on oral food intake--during the first postnatal days. Unselective screening methods are applied in neonatal mass screening programs for the early detection of metabolic diseases. In cases of unspecific clinical symptoms selective screening procedures may provide an effective diagnostic tool. If a patient with suspected metabolic disease dies, body fluids and organ biopsies should be preserved for further investigations. The establishment of a genotypspecific (enzyme) diagnosis needs time and cost consuming biochemical procedures. It is a prior condition for prenatal diagnosis in further pregnancies.

Mucopolysaccharidosis I and intracranial tumor in a patient with high-pressure hydrocephalus.

In a 19-month-old patient with mucopolysaccharidosis I (Pfaundler-Hurler, MPS I/H) high-pressure hydrocephalus required the implantation of a ventriculo-peritoneal shunt. Despite a reduction in both ventricular volume and intracranial pressure, clinical symptoms suggesting compression of the brain stem persisted. Brain MRI revealed a tumor within the posterior cranial fossa. Cytologic examination of the cerebrospinal fluid was suggestive of a poorly differentiated ependymoma. High-pressure hydrocephalus is a common complication in MPS I/H. As changes in mucopolysaccharide metabolism may be associated with an increased risk of developing neoplasms, the possibility of an intracranial tumor should be considered in patients with MPS I/H and high-pressure hydrocephalus.

Liposomal amphotericin-B (AmBisome) for treatment of cutaneous widespread candidosis in an infant with methylmalonic acidaemia.

In a 10-week-old infant with vitamin B12-unresponsive methylmalonic acidaemia, cutaneous candidosis (Candida albicans) progressed rapidly despite topical antifungal treatment. After 1 week of intravenous therapy with liposomal amphotericin-B (AmBisome) the dermatitis disappeared completely and blood cultures were sterile. No side-effects were observed. This is one of the first experiences in the treatment of infants with this new antifungal agent.

Glyceroltrioleate/glyceroltrierucate therapy in 16 patients with X-chromosomal adrenoleukodystrophy/adrenomyeloneuropathy: effect on clinical, biochemical and neurophysiological parameters.

UNLABELLED: We have investigated the effect of glyceroltrioleate/glyceroltrierucate (GTO/GTE) therapy on X-chromosomal adrenoleukodystrophy in 16 patients with adrenoleukodystrophy (n = 6), adrenomyeloneuropathy (n = 3), Addison disease without neurological involvement (n = 2), and neurologically and endocrinologically asymptomatic patients (n = 5). Therapy was carried out for 19.4 +/- 10 months. All patients showed a normalization of C 26:0 plasma fatty acid concentrations. None of the seven neurologically asymptomatic patients developed neurological symptoms. Somatosensory evoked potentials of the tibialis nerve was the most sensitive electrophysiological parameter, showing a slight improvement in neurologically asymptomatic patients during therapy. In none of the patients with normal cranial MRI at start of therapy (n = 6) has MRI deterioration been observed whilst on therapy. Follow up of the neurologically asymptomatic children supports the hypothesis that GTO/GTE therapy might prevent the development of neurological symptoms. Six of the nine neurologically symptomatic patients deteriorated to varying degrees whilst on therapy. MRI alterations have worsened in all patients with clinical deterioration. CONCLUSION: GTO/GTE treatment should be initiated in all neurological asymptomatic boys before first neurological symptoms develop. To discover these patients very long-chain fatty acid determination should be performed in all family members at risk when adrenoleukodystrophy or adrenomyeloneuropathy is diagnosed.

Symmetric hypoplasia of the temporal cerebral lobes in an infant with glutaric aciduria type II (multiple acyl-coenzyme A dehydrogenase deficiency).

Symmetric hypoplasia of the temporal cerebral lobes was demonstrated by magnetic resonance imaging of the brain in a macrocephalic male patient with glutaric aciduria type II within the first week of life. Psychomotor development was normal until the age of 11 months, when the patient died of sudden cardiac arrest. Autopsy revealed symmetric hypoplasia of the temporal cerebral lobes with loss of axons and hypomyelination in the temporal medullary layers.

Guanidinoacetate methyltransferase deficiency: the first inborn error of creatine metabolism in man.

In two children with an accumulation of guanidinoacetate in brain and a deficiency of creatine in blood, a severe deficiency of guanidinoacetate methyltransferase (GAMT) activity was detected in the liver. Two mutant GAMT alleles were identified that carried a single base substitution within a 5' splice site or a 13-nt insertion and gave rise to four mutant transcripts. Three of the transcripts encode truncated polypeptides that lack a residue known to be critical for catalytic activity of GAMT. Deficiency of GAMT is the first inborn error of creatine metabolism. It causes a severe developmental delay and extrapyramidal symptoms in early infancy and is treatable by oral substitution with creatine.

The cerebrohepatorenal (Zellweger) syndrome: an improved method for the biochemical diagnosis and its potential value for prenatal detection.

The sequence of reactions involved in plasmalogen biosynthesis has been evaluated in cultured fibroblasts of patients with the cerebrohepatorenal syndrome. A double-label, double-substrate incubation using [1-14C] hexadecanol and 1-0-[9', 10'-3H]hexadecylglycerol was performed to monitor the relative rates of peroxisomal and microsomal biosynthesic steps. [14C] radioactivity associated with 1'-alkenyl groups of plasmalogens was found to be drastically reduced in fibroblasts of affected patients whereas [3H] incorporation was apparently normal. This finding is specific for cerebrohepatorenal syndrome fibroblasts since cell lines of patients with childhood adrenoleukodystrophy and neuronal ceroidlipofuscinosis utilized the lipid precursors of plasmalogen biosynthesis at normal rates. The results show that the defect in plasmalogen synthesis in the cerebro-hepato-renal syndrome is restricted to the peroxisomal steps. The finding of normal microsomal biosynthetic steps was exploited to devise a novel diagnostic assay in fibroblasts and amniocytes based on the comparison of [3H/14C] isotope ratios within aldehydes released from plasmalogens by acid hydrolysis. The procedure can be completed with a minimal amount of cells since it renders quantitative analyses unnecessary. Therefore, this technique appears ideally suited for the sensitive and safe prenatal diagnosis of the cerebro-hepato-renal syndrome.

[Blood propionic acid with hyperammonemic coma]. / Propionazidämie mit hyperammoniämischem Koma.

We report on a mature male newborn who presented clinically on the 2nd day of live with poor feeding and acidotic breathing. Laboratory findings like severe metabolic acidosis, hyperammonemia, hyperglycinemia, ketonuria and elevated urinary excretion of lactate and propionate suggested the presence of organoacidopathia. Propionic acidemia, however could be diagnosed definitively only when the characteristic urinary and blood metabolites were found during the state of a hyperammonemic coma provoked by a fully oral protein regimen. The diagnosis was affirmed by reduced propionate fixation and by reduced propionyl-CoA-carboxylase shown in the patient's skin fibroblasts.

Factors involved in the pathogenesis of unexpected near miss events of infants (ALTE).

Near miss events or apparent life threatening events (ALTE) are considered preliminary stages of sudden infant death syndrome (SIDS). The current definition of near miss SIDS postulates that such an event happens unexpectedly and that no life threatening cause of disease can be detected. However in 32 of 34 observations of ALTE pathological changes actually could be identified by through investigations: 11 central nervous diseases, 10 respiratory tract disturbances, 5 metabolic abnormalities, 5 disturbances of the digestive tract and 1 cardiac disease. There were 22 morphologically manifested causes as opposed to 10 functional failures mainly respiratory control and oesophageal disturbances. Irrespective of the main diagnosis sleep apnea syndrome (SAS) could be detected in 17 of 28 infants combined with bradycardia in 5 cases, and oesophageal disturbances in 16 of 17 infants. Four babies later died, two of them suffered from carnitine deficiency and one from organic acidopathy. It is our conclusion that numerous, even banal causes of disease are able to trigger ALTE if there is a coincidence with phases of increased instability of vital regulatory mechanisms of autonomous centres in infants.