Propionic acidemia revisited: a workshop report.

Propionic acidemia (PA) is one of the most frequent organic acidurias, but information on the outcome of individuals with PA is rather limited. We present data of 49 patients with PA, which were gathered from 18 metabolic centers throughout Central Europe on the occasion of an international workshop. All patients were identified by selective metabolic screening, and 86% of them were classified as having early-onset PA owing to their presentation with clinical symptoms within the first 90 days of life. Mortality rate was one third, and details of symptoms and treatment of the surviving patients are discussed. The great variation of phenotypic expression of the disease and different therapeutic strategies (especially in regard to the degree of protein restriction) used at the various institutions involved in this study imply the need for a registry of PA patients and for a multicenter prospective treatment study.

Trichothiodystrophy: quantification of cysteine in human hair and nails by application of sodium azide-dependent oxidation to cysteic acid.

The term "trichothiodystrophy" (TTD) covers several autosomal recessive diseases whose diagnostic hallmark is short, brittle hair low in sulfur and cystine because of impaired synthesis of high-sulfur matrix protein. Clinical symptoms associated with TTD represent a variable range of abnormalities in organs derived from ectoderm and neuroectoderm. Important laboratory tests of the hair for the diagnosis of TTD comprise polarizing microscopy ("tiger-tail" pattern), electron microscopy, and amino acids analysis of hydrolyzed hair with a special focus on cystine. However, only very few institutions determine the amino acid composition of human hair and nail clippings, which requires special sample preparation including hydrolysis. If no special precautions are taken, quantification of cysteine and cystine becomes inaccurate because of decomposition of these residues during hydrolysis. We therefore performed the sample work-up with azide-dependent oxidation which we have for the first time adapted for analysis of hair and nail clippings. With our control and parent data resembling published data on hair and nail samples, we obtained a decreased proportion of cysteine (half cystine, determined as cysteic acid) in materials obtained from a boy with TTD. Clearly, the method for the quantification of cysteine following sodium azide-dependent oxidation is a suitable and rather convenient approach to the quantification of cyst(e)ine and other amino acids in hair and nail proteins, and is a valuable contribution to the diagnosis of TTD.

The clinical spectrum of mitochondrial disease in 75 pediatric patients.

The clinical presentation of mitochondrial disorders in childhood is highly variable causing difficulties in diagnosis and management. We assessed records of 75 children (48 male, 27 female) with a biochemically and/or molecularly established mitochondrial disorder in a retrospective, multicentric study. The predominant biochemical defect was an isolated respiratory chain complex IV, followed by respiratory chain complex I, combined respiratory chain, and isolated pyruvate dehydrogenase complex (PDHC) deficiencies. For the 75 patients, the predominant clinical presentations were a nonspecific encephalomyopathy (n = 34) and Leigh syndrome (n = 17). Classical mitochondrial syndromes with associated mutations of the mitochondrial DNA were rare (n = 12). Eleven children had a lethal infantile mitochondrial disease (LIMD). This group comprised a considerable variety of clinical pictures, and the cohort was big enough to show the high frequency and wide spectrum of nonneuromuscular symptoms in mitochondrial disorders in childhood.

Clinical heterogeneity in patients with mutations in the NDUFS4 gene of mitochondrial complex I.

A comparison of the clinical presentation, disease course and results of laboratory and imaging studies of all patients so far published with a NDUFS4 mutation are presented. This reveals marked clinical heterogeneity, even in patients with the same genotype.

Clinical and experimental results on cardiac troponin expression in Duchenne muscular dystrophy.

BACKGROUND: Because of controversial earlier studies, the purpose of this study was to provide novel experimental and additional clinical data regarding the possible reexpression of cardiac troponin T (cTnT) in regenerating skeletal muscle in Duchenne muscular dystrophy (DMD). METHODS: Plasma from 14 patients (mean age, 7.5 years; range, 5.7-19.4 years) with DMD was investigated for creatine kinase (CK), the CK MB isoenzyme (CKMB), cTnT and cardiac troponin I (cTnI), and myoglobin. cTnT concentrations were measured by an ELISA (second-generation assay; Roche) using the ES 300 Analyzer. cTnI, myoglobin, and CKMB were measured by an ELISA using the ACCESS System (Beckman Diagnostics). Troponin isoform expression was studied by Western blot analysis in remnants of skeletal muscle biopsies of three patients with DMD and in an animal model of DMD (mdx mice; n = 6). RESULTS: There was no relation of cTnT and cTnI to clinical evidence for cardiac failure. cTnI concentrations remained below the upper reference limit in all patients. cTnT was increased (median, 0.11 microg/L; range, 0.06-0.16 microg/L) in 50% of patients. The only significant correlation was found for CK (median, 3938 U/L; range, 2763-5030 U/L) with age (median, 7.5 years; range, 6.8-10.9 years; r = -0.762; P = 0.042). Western blot analysis of human or mouse homogenized muscle specimens showed no evidence for cardiac TnT and cTnI expression, despite strong signals for skeletal muscle troponin isoforms. CONCLUSIONS: We found no evidence for cTnT reexpression in human early-stage DMD and in mdx mouse skeletal muscle biopsies. Discrepancies of cTnT and cTnI in plasma samples of DMD patients were found, but neither cTnT nor cTnI plasma concentrations were related with other clinical evidence for cardiac involvement.

Predicting survival infants ventilated with high-frequency oscillation.

UNLABELLED: This retrospective study identifies factors which may predict outcome in preterm infants and infants born at term, ventilated with high-frequency oscillation (HFO). In a 16-bed neonatal and paediatric intensive care unit (level III), 58 consecutive preterm and term infants with a median gestational age of 30 (24-41) weeks and a median birth weight of 1200 (520-3660) g suffered respiratory failure and were managed with HFO as rescue therapy. Forty-nine patients (84%) received exogenous surfactant before HFO which was initiated after a median interval of 20 (1-910) hours following birth. The overall survival rate was 70%. No significant differences existed between survivors and nonsurvivors in respect to demographic data. A greater proportion of patients with respiratory distress syndrome survived (76%) than with lung hypoplasia (20%) or with air-leak syndromes (pulmonary interstitial emphysema 60%, pneumothorax 28%). In survivors, the mean oxygenation index (OI) before HFO was significantly lower than that in nonsurvivors (16 +/- 1.3 vs. 26 +/- 3, p < 0.01) and showed a significant reduction of 32% within 4 hours. In contrast, mean OI increased to 68% over the first 4 hours in nonsurvivors and the difference between survivors and nonsurvivors remained significant during this time (after 2 hours: 15 +/- 1.5 vs. 30 +/- 6, p < 0.01; after 4 hours: 11 +/- 1 vs. 43 +/- 1, p < 0.01). A receiver of operator analysis revealed that an initial OI < 25 or alveolar-arterial oxygen difference (AaDO2) < 450 mmHg predicted survival with a sensitivity of 93% and a specificity of 41%. The positive predictive value was 79%; the negative predictive value, 70%. CONCLUSION: A low OI and AaDO2 at the beginning of HFO, improvement in oxygenation over the first four hours of HFO ventilation and no development of air-leak syndromes were associated with a high predicted survival. This allows early identification of infants who may not survive and may benefit from established and alternative modes of respiratory support such as extracorporeal membrane oxygenation, nitric oxide and liquid ventilation.

Oral creatine supplementation in Duchenne muscular dystrophy: a clinical and 31P magnetic resonance spectroscopy study.

The decrease in intracellular creatine concentration in Duchenne muscular dystrophy may contribute to the deterioration of intracellular energy homeostasis and may thus be one of the factors aggravating muscle weakness and degeneration. Oral creatine supplementation should have potential in alleviating the clinical symptoms. To test this hypothesis, creatine was orally administered over a period of 155 days to a 9-year-old patient with Duchenne muscular dystrophy. In accordance with previous investigations on normal subjects and trained athletes, the patient experienced improved muscle performance during creatine supplementation. Further evidence supporting this hypothesis derived from plasma creatine kinase and lactate dehydrogenase activities and repeated 31P magnetic resonance spectroscopy of the gastrocnemius muscle. These preliminary observations indicate a potential role for creatine supplementation in the symptomatic therapy of patients with muscle disease.

[SIDS prevention program in Tyrol]. / Das SIDS-Vorsorgeprogramm Tirol.

In April 1994, an intervention campaign to reduce the incidence of sudden infant death syndrome (SIDS) was established in the Tyrol. The campaign was intended to increase knowledge concerning risk factors for SIDS in the general community and to improve individual care for infants at risk. In contrast to interventional programmes in other federal states of Austria (i.e. Vorarlberg, Styria), this programme did not utilise polysomnography for identifying infants at risk. A part of the intervention programme was the "Styrian risk questionnaire", a standardised questionnaire concerning risk factors for SIDS. Individual instructions for health care of children at risk (risk score > or = 7) were provided and, if necessary, subscription of home monitoring was performed at the out-patient department (SIDS out-patient service) of the Department of Paediatrics in Innsbruck and other paediatric departments throughout the Tyrol. The educational programme also included information concerning basic life support. Psychological support was offered to parents of SIDS infants. Risk factors for SIDS in the Tyrol before the campaign were assessed in a retrospective case-control study (time period 1984-1994; 99 SIDS infants, 136 controls). The risk of SIDS was markedly reduced when parents had detailed knowledge of the risk factors of SIDS (odds ratio (OR) 0.03; p < 0.001), which emphasises the importance of information and educational programmes. The incidence of SIDS declined after the beginning of the intervention campaign from 1.83/1000 live births (average incidence from 1984-1994) to 0.4/1000 live births and remained at this level thereafter. Post-neonatal mortality also declined from 3.9 to 1.3/1000 live births. The prevalence of the prone sleeping position declined immediately after the campaign (53.7% vs. 5.4%, p < 0.001), as did the frequency of maternal smoking during pregnancy (22.9% vs. 14.5%, p < 0.01). Breast feeding became more popular. In all, the low-cost intervention programme in the Tyrol proved to be highly efficient in reducing the risk of SIDS and in maintaining this effect for several years.

Elevated plasma bile acid concentrations in two sisters with tyrosinaemia type I.

A 21-month-old girl suffering from tyrosinaemia type I and undergoing treatment with 2-(2-nitro-4-trifluoro-methylbenzoyl)-1,3-cyclohexanedione (NTBC) presented with pruritus which rapidly ceased with administration of high doses of ursodeoxycholic acid. Determination of plasma bile acids revealed clearly elevated levels both in samples taken before and after the onset of NTBC therapy, thus indicating, that the increase was not related to the administration of this drug. This result is corroborated by data from the first patient's newborn sister, diagnosed with the same disease, who showed elevated plasma bile acid concentrations in all samples examined, except for the cord plasma. This is the first report on altered bile acid concentrations in tyrosinaemia type I, and underlines the need for thorough investigation of bile acid metabolism in this disease.

Odd-numbered long-chain fatty acids in propionic acidaemia.

UNLABELLED: In patients with propionic acidaemia (PA), the increased intracellular concentration of propionyl-CoA leads to a relative abundance of odd-numbered long-chain fatty acids (OLCFAs) in body lipids. We investigated the relative amount of OLCFA in erythrocyte membrane lipids over a period of 1-8 years in five patients with early onset PA and present their clinical outcome. After extraction from erythrocyte membrane lipids and esterification, fatty acids were analysed by capillary column gas chromatography. The sum of the OLCFA 15- and 17- carbon saturated and 17-carbon monounsaturated fatty acids (C15:0, C17:0, C17:1) was calculated and expressed as a percentage of the total C14-C22 fatty acids in the sample. Three patients (pccBC-complementation group) presented with a stable clinical course and showed OLCFA values usually below 1.9% (median % +/- SD: 1.4+/-0.5, 1.6+/-0.5, 1.8+/-0.5). Two patients (pccA-complementation group) had a more severe course of the disease and showed higher medians and a broader range of OLCFA levels (2.2+/-1.2 and 2.2+/-0.8). CONCLUSION: Our study shows that odd-numbered long-chain fatty acid concentrations are increased in patients with propionic acidaemia and are higher in those with a more severe clinical course. The value of odd-numbered long-chain fatty acids in the assessment of the phenotypic severity and in the management of propionic acidaemia remains to be proven in a prospective long-term study with more patients of differing phenotype.

Plasma concentrations and renal clearance of orotic acid in argininosuccinic acid synthetase deficiency.

Argininosuccinic acid synthetase deficiency (ASD) is a rare disorder of urea cycle metabolism, with pronounced citrullinemia and orotic aciduria being characteristic biochemical features. To further investigate the role of plasma orotic acid and its possible use for monitoring the metabolic status in ASD, we determined plasma orotic acid, amino acid, and ammonium levels in plasma samples collected over a period of 3 years from a patient who is now 8 years of age. Orotic acid plasma concentrations varied widely from less than 1 micromol/l to more than 60 micromol/l. The renal clearance of orotic acid was eightfold the glomerular filtration rate, thus supporting an active mechanism underlying the excretion of this pyrimidine. Data obtained during a metabolic crisis yielded a statistically significant linear correlation of orotic acid plasma levels with those of glutamine and ammonium, which are generally accepted for assessment of the successful treatment of this disorder. Our data revealed no advantage of plasma orotic acid concentrations over the established amino acids (glutamine and arginine) and ammonium for determining acute treatment responses. Since several effects of high levels of orotic acid have been described in mammals, further research is necessary to assess a possible contribution of orotic acid to the pathogenesis of ASD and the use of plasma orotic acid levels in the long-term monitoring of these patients.

Complications of percutaneous insertion of Hickman catheters in children.

BACKGROUND/PURPOSE: The aim of this study was a retrospective evaluation of insertion and management complications of percutaneous Hickman catheter lines in pediatric patients to investigate whether the complication rate is acceptable in comparison with other insertion methods or other age groups. METHODS: Over a period of 22 months a total of 27 Hickman catheters were inserted in 22 pediatric patients (20 oncological, 2 nononcological; age 6 weeks to 17.5 years). RESULTS: Twenty-three of 36 insertion attempts (63.9%) were successful at first attempt. In another 4 patients, catheters were placed after repeated attempts. In an additional 4 patients, catheters were inserted by surgeons after percutaneous insertion failed. As immediate complications, 1 pneumothorax and 1 malposition were seen. Late complications included 1 to 29 (median, 8) days of fever in 15 patients, corresponding to 53 of 1,000 catheter days. Fourteen patients showed 21 positive blood cultures, including 11 cases of Staphylococcus epidermides, which might be related to the catheter. Antibiotics were given for a total of 1 to 130 (median, 35) days, that is 205 of 1,000 catheter days. No catheter was removed because of infectious complications. The total life span of the Hickman catheters was 1 to 371 (median, 163) days, the patients were in the hospital from 1 to 351 (median, 102) days because of their underlying disease. At the end of the study period, 8 of 27 (29.6%) catheters remained functioning in situ; 9 (33.3%) had been selectively removed. Two patients died with the catheter (7.4%) functioning well. Another 2 patients showed catheter thrombosis. Six catheters (22.2%) in 5 patients showed inadvertent dislodgement. CONCLUSION: Percutaneous Hickman catheter insertion in pediatric patients is effective; however, complication rate is relevant, but not higher than percutaneous insertion of subclavian vein or Hickman catheters in adults.

Identification of novel mutations in the PCCB gene in European propionic acidemia patients. Mutation in brief no. 253. Online.

Propionyl-CoA carboxylase (PCC) is a biotin-dependent enzyme located in the mitochondrial matrix. Mutations in the PCCA and PCCB genes, which encode the a and b subunits of this heteropolymer, result in propionic acidemia (PA). We report the molecular analysis of b-deficient patients from Spain and Austria. Subjects were screened for defects affecting the PCCB gene by direct sequencing from genomic PCR products, restriction digests and mRNA analysis by RT-PCR. Study by western blot of the presence of immunoreactive b-PCC protein was also performed. A total of four novel sequence variations were found including the point mutations V205D, and M442T, and the frameshift mutation 790-791insG. Additionally, a new point change, L17M, was identified on the same allele as 790-791insG. The missense changes described above were not found in at least 40 control chromosomes analyzed. The Austrian patients were homozygous for V205D. One of the Spanish subjects was heterozygous for M442T and the known mutation c1170insT. The other Spanish patient carried L17M+790-791insG on one allele, and the described mutation E168K on the other mutant chromosome. The mutations V205D and M442T were confirmed at RNA level and also we have detected the presence of immunoreactive b-PCC protein translated from these mutant alleles. The patient having L17M+790-791insG and E168K also presented immunoreactive b-PCC protein. However, no cDNA product was obtained from the chromosome carrying L17M+790-791insG. We propose that 790-791insG, which causes a frameshift and a premature stop codon, is responsible for this finding. In any case, the translation from this mutant cDNA would produce a severity truncated peptide and, in consequence, a non-functional protein. Expression analysis of all these changes will help us to clarify their structural/functional consequences.

Different clinical aspects of debrancher deficiency myopathy.

OBJECTIVE: To characterise the main clinical phenotypes of debrancher deficiency myopathy and to increase awareness for this probably underdiagnosed disorder. METHODS: The diagnosis of debrancher deficiency was established by laboratory tests, EMG, and muscle and liver biopsy. RESULTS: Four patients with debrancher deficiency myopathy were identified in the Tyrol, a federal state of Austria with half a million inhabitants. Clinical appearance was highly variable. The following phenotypes were differentiated: (1) adult onset distal myopathy; (2) subacute myopathy of the respiratory muscles; (3) severe generalised myopathy; and (4) minimal variant myopathy. Exercise intolerance was uncommon. The clinical course was complicated by advanced liver dysfunction in two patients and by severe cardiomyopathy in one. All had raised creatine kinase concentrations (263 to 810 U/l), myogenic and neurogenic features on EMG, and markedly decreased debrancher enzyme activities in muscle or liver biopsy specimens. The findings were substantiated by a review of 79 previously published cases with neuromuscular debrancher deficiency. CONCLUSIONS: This study illustrates the heterogeneity of neuromuscular manifestations in debrancher deficiency. Based on the clinical appearance, age at onset, and course of disease four phenotypes may be defined which differ in prognosis, frequency of complications, and response to therapy.

Normal ascorbic acid in cerebrospinal fluid of patients with infantile neuronal ceroid-lipofuscinosis.

Neuronal ceroid-lipofuscinoses (NCL) are a group of neurodegenerative disorders. There is much evidence for a role of peroxidation processes in the pathogenesis of NCL, although this would certainly be indirect. Reduced total antioxidant activity of cerebrospinal fluid (CSF) has been reported in NCL. Since ascorbic acid represents a major antioxidant in CSF, we have now determined this parameter in CSF of two patients with the infantile form of NCL (Santavuori-Haltia disease). However, the ascorbic acid values obtained (103.6 and 181.3 microM) are comparable with control values from the literature as well as with those measured in groups of children with neurologic/psychiatric diseases other than NCL (mean +/- standard deviation: 137.1+/-41.3 microM), with suspected (but excluded) meningitis (124.1+/-34.0 microM) and acute lymphoblastic leukemia (131.7+/-17.0 microM). Our results indicate that CSF ascorbic acid concentrations are not affected by peroxidation processes in infantile NCL, but reveal a sharply decreased ascorbic acid concentration in one of the non-NCL patients, possibly associated with his convulsions and/or his anticonvulsant therapy.