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Biomedical subjects

D Rabier

Publications and source records attributed to D Rabier.

At least 55 records · Page 3Linked to original sources
PubMed1998

Defective peroxisome biogenesis with a neuromuscular disorder resembling Werdnig-Hoffmann disease.

OBJECTIVE: Characterization of the defect in a patient presenting a peripheral neuropathy with atypical features of distal motor involvement mimicking Werdnig-Hoffmann disease. PATIENT: Clinical signs included generalized hypotonia and floppiness, absence of stretch reflexes, muscle wasting, lack of head control and lingual fasciculations associated with unaffected facial muscles, and normal intellectual development. RESULTS: Normal muscle histology ruled out Werdnig-Hoffmann disease. Elevated plasma concentrations of very long-chain fatty acids and bile acid intermediates combined with normal plasmalogen levels in erythrocytes suggested defective peroxisomal beta-oxidation directly demonstrated by deficient pristanic acid and partially deficient C26:0 was present oxidation in cultured fibroblasts. Severely impaired pipecolic acid oxidation in liver and phytanic acid oxidation in fibroblasts was present. On light and electron microscopy of the liver tissue, rare peroxisomal membrane ghosts and trilamellar inclusions but absence of peroxisomes was noted. Immunoblot analysis revealed absence of peroxisomal beta-oxidation enzymes in liver tissue but normal results in fibroblasts. Remarkably, expression of the peroxisomal defect in fibroblasts was indicated by the finding of mainly cytoplasmatic catalase, as in liver. Preliminary studies excluded classification of this patient within the large PEX1 complementation group. CONCLUSIONS: The results suggest a novel peroxisome biogenesis disorder involving peroxisomal beta-oxidation as well as phytanic and pipecolic acid oxidation rather than an isolated defect of peroxisomal beta-oxidation. The association of a clinical picture mimicking Werdnig-Hoffmann disease with a novel peroxisomal disorder raises the question of whether investigation for peroxisomal function should be considered in every patient with an enigmatic spinal muscular atrophy-like syndrome.

Bile Acids and Salts↗
PubMed1997

Tolerance to starvation in children on long-term total parenteral nutrition.

To evaluate the consequences of long-term cyclic total parenteral nutrition (TPN) on metabolic pathways which contribute to energy metabolism, adaptation to starvation was studied in a group of seven children 2-7 years old, on long-term cyclic TPN. In addition to clinical monitoring, the following biological parameters were measured: blood levels of glucose, free fatty acids, ketone bodies and carnitine, and urinary excretion of dicarboxylic acids. Five of the seven children had good clinical tolerance up to 30 h of fasting. This indicated that metabolic changes arising from prolonged cyclic TPN are easily reversed when such children are fasting. The other two children had to be refed after 22 and 24 h, respectively. Both had metabolic signs of impaired hepatic fatty acid oxidation or ketogenesis. These metabolic changes might reflect the liver failure caused by TPN in these children, and stresses the fact that prolonged starvation has to be carefully monitored in patients with liver dysfunction secondary to TPN.

Journal Article↗
PubMed1997

[Variation of amino acids in relation to age in Down syndrome subjects].

BACKGROUND: A preliminary study of plasma and urinary amino acid concentration in Down's syndrome subjects had shown some impairments. PATIENTS AND METHODS: A comparative study of the variations of amino acid concentration with age in Down's syndrome subjects aged 0 to 60 years and in control subjects aged 0 to 94 years was made in order to determine whether these impairments could be explained by generalized premature aging, or by a specific gene dosage effect. RESULTS: Two major changes (P < 0.001) were found in Down's syndrome: a decrease in plasma concentration of serine at any age, which could be due to a dosage effect of cytathionine-beta-synthase, and an increase in plasma lysine concentration in patients above 10 year's old, probably due to premature aging. Other minor changes were also present in plasma and urine, also possibly explained by premature aging. CONCLUSIONS: Other studies are necessary to evaluate possible consequences of such changes in the amino acid profiles.

Adolescent↗
PubMed1997

Continuous venovenous haemodiafiltration in the acute phase of neonatal maple syrup urine disease.

Maple syrup urine disease results in accumulation of leucine and its metabolites, which may lead in the long term to neurological dysfunction. In acute neonatal crises, large amounts of leucine may be removed by continuous venovenous haemofiltration. This extracorporeal technique has its risks and hazards, which increase with duration of treatment. We report three neonates in life-threatening conditions due to maple syrup urine disease, treated for not more than 12 h with various continuous venovenous techniques: continuous haemofiltration, haemodiafiltration and haemodialysis. The efficiency of and tolerance to these techniques was evaluated. For all three patients, plasma leucine levels decreased dramatically from 2186, 3818 and 2536 mumol/L to 1131, 1275 and 488 mumol/L, respectively. Leucine clearance obtained was 4.28 ml/min in haemodiafiltration. Their patients' neurological status improved rapidly and they have a normal developmental quotient at 22 months, 13 months, and 11 months of age, respectively. Tolerance was good except for hypothermia and drop in haematocrit in all cases. Haemodiafiltration management was more cumbersome and time consuming because it required continual adjustment of the substitution fluid flow rate to precisely balance inflow and outflow rates. We recommend continuous venovenous haemodialysis as the therapy of choice. It might be anticipated that improvement of this technique, by increasing dialysate flow rate and blood flow rate, will allow leucine concentration to be decreased below 1000 mumol/L within 6-8 h, whatever the initial level.

Acute Disease↗
PubMed1997

The clinical phenotype of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria): case reports of 23 new patients.

OBJECTIVES: To further define the clinical spectrum of the disease for pediatric and metabolic specialists, and to suggest that the general pediatrician and pediatric neurologist consider succinic semialdehyde dehydrogenase (SSADH) deficiency in the differential diagnosis of patients with (idiopathic) mental retardation and emphasize the need for accurate, quantitative organic acid analysis in such patients. PATIENTS: The clinical features of 23 patients (20 families) with SSADH deficiency (4-hydroxybutyric acid-uria) are presented. The age at diagnosis ranged from 3 months to 25 years in the 11 male and 12 female patients; consanguinity was noted in 39% of families. OUTCOME MEASUREMENTS: The following abnormalities were observed (frequency in 23 patients): motor delay, including fine-motor skills, 78%; language delay, 78%; hypotonia, 74%; mental delay, 74%; seizures, 48%; decreased or absent reflexes, 39%; ataxia, 30%; behavioral problems, 30%; hyperkinesis, 30%; neonatal problems, 26%; and electroencephalographic abnormalities, 26%. Associated findings included psychoses, cranial magnetic resonance or computed tomographic abnormalities, and ocular problems in 22% or less of patients. Therapy with vigabatrin proved beneficial to varying degrees in 35% of the patients. Normal early development was noted in 30% of patients. CONCLUSIONS: Our data imply that two groups of patients with SSADH deficiency exist, differentiated by the course of early development. Our recommendation would be that accurate, quantitative organic acid analysis in an appropriate specialist laboratory be requested for any patients presenting with two or more features of mental, motor, or language delay and hypotonia of unknown cause. Such analyses are the only definitive way to diagnose SSADH deficiency; the diagnosis can be confirmed by determination of enzyme activity in white cells from whole blood. We think that increased use of organic acid determination will lead to increased diagnosis of SSADH deficiency and a more accurate representation of disease frequency. As additional patients are identified, we should have a better understanding of both the metabolic and clinical profiles of SSADH deficiency.

Adolescent↗
PubMed1996

Gestational age-related reference values for amniotic fluid amino acids: a useful tool for prenatal diagnosis of aminoacidopathies.

In this study we have measured the concentration of 24 amino acids and total homocysteine in amniotic fluids obtained between the tenth and 32nd week of gestation from pregnancies not at risk for metabolic diseases. These results are used as reference values to which are compared values obtained from pregnancies at risk for citrullinaemia, argininosuccinic aciduria, HHH (hyperornithinaemia, hyperammonaemia and homocitrullinaemia) syndrome, cobalamin metabolism disorders (CblC or CblD), and sulphite oxidase deficiency. We discuss the helpfulness of amino acid analysis in amniotic fluid for prenatal diagnosis of aminoacidopathies.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

Metabolic intermediates in lactic acidosis: compounds, samples and interpretation.

A number of acquired conditions including infections, severe catabolic states, tissue anoxia, severe dehydration and poisoning can give rise to hyperlactacidaemia. All these causes should be ruled out before considering inborn errors of metabolism. Carefully collected samples are necessary if artefacts that result in spuriously increased lactate/pyruvate (L/P) and 3-hydroxybutyrate/acetoacetate (B/A) ratios are to be avoided. When properly performed, 24-h studies of L/P and B/A ratios provide a useful tool in making a diagnosis. A few metabolic profiles when present are specific or highly suggestive of a given disorder. When the L/P ratio is normal or low, pyruvate dehydrogenase (PDH) deficiency is highly probable whatever the lactate concentration, which is often only moderately elevated after meal, may be. When the L/P ratio is very high in association with post-prandial hyperketonaemia and in contrast to a normal or low B/A ratio, pyruvate carboxylase (PC) deficiency and alpha-ketoglutarate dehydrogenase (KGDH) deficiency are the most likely diagnoses. The distinction between the two disorders relies upon amino acid and organic acid profiles (glutamate and alpha-ketoglutarate accumulations in KGDH deficiency and hyperammonaemia and hypercitrullinaemia in PC deficiency). When both L/P and B/A ratios are elevated and associated with significant post-prandial hyperketonaemia, respiratory-chain disorders should first be suspected. All other profiles, especially a high L/P ratio without hyperketonaemia, are compatible with respiratory-chain disorders but are not specific; all acquired anoxic conditions should also be ruled out. Clearly, the clinical utility of these profiles needs to be interpreted cautiously in very ill patients in relation to the cardiocirculatory condition and to therapy. Finally, a normal profile, even after stress and loading, does not rule out an inborn error of lactate/pyruvate oxidation.

Acidosis, Lactic↗
PubMed1996

Clinical outcome and long-term management of 17 patients with propionic acidaemia.

UNLABELLED: A retrospective study was performed on the clinical outcome and long-term treatment of 17 patients with propionic acidaemia diagnosed during the last 20 years in our hospital. The study group consisted of 12 patients with early onset type of disease and 5 patients with late onset. Seven (41%) patients died, five with early onset and two with late onset. The deceased early onset patients had a median survival of 0.4 years while the deceased late onset patients died at the age of 2.8 and 4 years respectively. Median age of the living early onset patients was 5.2 (1-9.25) years, the late onset patients were 4, 7 and 23 years old. Patients were all treated with natural protein restriction and in most cases carnitine and metronidazole were added. The early onset patients were almost all treated with daily home tube feeding. The mean natural protein intake of early onset patients (6.3 +/- 1.5 g/day) was significantly lower than the natural protein intake of late onset patients (17.6 +/- 5.3 g/day). Supplemental protein intake was higher in early onset patients. The general neurological outcome of our study group was satisfactory with a better outcome for early onset patients. As to growth, many patients showed a failure to thrive, this was particularly for height. The strong protein restriction during the first years of life probably contributed to this. CONCLUSION: The prognosis for patients with propionic acidaemia appeared to be satisfactory in terms of survival and outcome characteristics such as neurological and mental development. Despite these results the authors feel that the prognosis and quality of life of these patients might be improved with liver transplantation or possibly somatic gene therapy in the future.

Adolescent↗
PubMed1996

Most cases of medium-chain acyl-CoA dehydrogenase deficiency escape detection in France.

DNA from 414 French blood donors from the Paris area was assessed for the A985G mutation responsible for most cases of autosomal recessive medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. The mutant gene frequency averaged 1/140, predicting a frequency of mutant homozygotes of 1/19 000. Discrepancy between the numbers of expected (42 per year) and recorded cases of MCAD (6 per year) suggests that most MCAD-deficient patients escape detection in France.

Acyl-CoA Dehydrogenase↗
PubMed1996

Hypopigmentation in hemodialysis. Acquired hair and skin fairness in a uremic patient undergoing maintenance hemodialysis: case report and review of the literature.

With recent advances in medicine, uremic patients are living longer with an improving quality of life. Several skin diseases have been reported in patients with chronic renal failure, and the opportunity has been offered to elucidate newer cutaneous abnormalities among patients undergoing long-term hemodialysis. Hyperpigmentation was the most prevalent cutaneous abnormality observed in these patients, but hypopigmentation remains an exceptional event. We report here a case of a maintenance hemodialysis patient with an acquired hair and skin fairness. Although the true mechanism involved in this entity remains obscure, it can be correlated with a disturbance of phenylalanine metabolism on the basis of the current knowledge.

Hair↗
PubMed1995

A scheme for the interpretation of primary and secondary disturbances of plasma and urinary amino acid profiles. A possible way to an expert system.

A general scheme for the interpretation of primary and secondary abnormalities of plasma and urine amino acid concentrations is described. The key steps of this scheme are: analytical assessment of the measurements, comparison of results obtained with the reference values expressed in absolute and/or relative concentrations and identification of abnormally increased ninhydrin-positive compounds. The interpretation of results takes account of the various abnormalities induced by drugs or diet. The origins of these abnormalities are ordered by their frequency. A part of the proposed scheme is now computerized as the first step in the development of an expert system.

Amino Acid Metabolism, Inborn Errors↗
PubMed1995

Apparent segregation of null alleles ascribed to deletions of the ornithine transcarbamylase gene in congenital hyperammonaemia.

Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle mapped to chromosome Xp21.1. Here, we show that apparent segregation of null alleles at the OTC locus and flanking polymorphic loci mimicked false maternity or false paternity in three affected families. Based on these observations, we suggest giving consideration to gene deletion when dealing with segregation of null alleles in OTC deficiency.

Alleles↗
PubMed1995

Liver transplantation in two cases of propionic acidaemia.

Orthotopic liver transplantation (OLT) was performed in two patients with propionic acidaemia, a 7-year-old boy and a 9-year-old girl, diagnosed with a severe neonatal form with high risk of metabolic decompensation. In both cases the metabolic liver functions recovered within the 12 postoperative hours; no clinical symptoms of propionic acid toxicity, metabolic acidosis, severe hyperammonaemia, hyperglycinaemia or haematological abnormalities were observed. In both cases insulin-dependent diabetes mellitus occurred early after OLT (persisting in the boy's case). Severe post-transplantation complications were observed (acute rejection and CMV infection in both patients) which did not trigger metabolic decompensation. The boy developed chronic rejection and vanishing bile duct syndrome due to incomplete hepatic arterial thrombosis. He required permanent in-patient care with chronic hyperammonaemia and neurological sequelae involving the basal ganglia and died 15 months after OLT. The girl left hospital after 2 months and is presently leading a normal life with almost no dietary protein restriction (40 g protein per day). Urinary urea excretion and daily protein intake increased after liver transplantation. Propionyl- and tiglylglycine disappeared immediately after OLT. Urinary methylcitrate and 3-hydroxypropionate remained at concentrations corresponding to those before OLT. However, the total of all characteristic metabolites of organic acid analysis was reduced to 50-60% of the values before OLT in both patients. Propionylcarnitine was still detected at significant concentrations. Plasma odd-chain fatty acid concentrations decreased continuously after OLT only in the girl's case. Tissue of both transplanted livers showed increased odd-chain fatty acid concentrations 9 and 15 months after OLT, respectively, in both patients. We consider that at present OLT should only be performed in severe forms of propionic acidaemia.

Acidosis↗
PubMed1995

Abnormal alpha-aminoadipic acid excretion in a newborn with a defect in platelet aggregation and antenatal cerebral haemorrhage.

alpha-Aminoadipic acid (alpha AA) is an intermediate in lysine metabolism. We report a new case with alpha AA excess in urine and plasma, without alpha-ketoadipic acid, in a full-term male child born to unrelated parents; he presented at 24h of life with seizures that failed to respond to phenobarbital, clonazepam, and Vigabatrin and death occurred on the 38th day of life. Brain imaging suggested antenatal haemorrhage. Small quantities of alpha AA were also detected in the blood and urine of both parents and a healthy brother, all three of whom exhibited the same defect in platelet aggregation as the deceased child. Both parents had decreased levels of plasma neopterin, a finding that might be related to the immunodeficiency described in other cases.

2-Aminoadipic Acid↗