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P M Coates

Publications and source records attributed to P M Coates.

At least 37 records · Page 2Linked to original sources
PubMed1992

Immunochemical characterization of variant medium-chain acyl-CoA dehydrogenase in fibroblasts from patients with medium-chain acyl-CoA dehydrogenase deficiency.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a common autosomal recessive disorder of mitochondrial fatty acid oxidation characterized by episodes of hypoketotic hypoglycemia usually beginning in the first 2 y of life. We previously showed, in pulse labeling experiments, that the biosynthesis and immediate posttranslational processing of MCAD are normal in fibroblasts from patients with MCAD deficiency. Most patients studied to date are homozygous for a point mutation (A985-G) that results in the substitution of glutamate for lysine ar residue 304 of the mature MCAD subunit. We performed immunoblot analysis of fibroblast MCAD from a total of 34 patients with MCAD deficiency, including 31 homozygous for the A985-G mutation, using a rabbit anti-rat MCAD antibody that cross-reacted specifically with human MCAD, but not with the related enzymes, short-chain and long-chain acyl-CoA dehydrogenases. All patients with the A985-G mutation lacked detectable MCAD. Pulse-chase labeling of MCAD-deficient fibroblasts with 35S-methionine demonstrated that this variant MCAD was unstable compared to controls. Taken together, these data suggest that this mutation affects the stability of MCAD protein within the mitochondrial matrix.

Acyl-CoA Dehydrogenase↗
PubMed1992

Molecular basis of mitochondrial fatty acid oxidation defects.

A dozen separate inherited disorders of mitochondrial fatty acid beta-oxidation have been described in humans. This represents about half of the potential sites for genetic error that can affect this important pathway of energy metabolism. As the characterization of these disorders at the clinical and biochemical levels has progressed rapidly, so has the delineation of the molecular defects that underlie them. The most commonly recognized disorder of beta-oxidation is medium-chain acyl-CoA dehydrogenase deficiency; a striking feature of this disorder is that there is a single point mutation that accounts for 90% of the variant alleles among patients with medium-chain acyl-CoA dehydrogenase deficiency. Molecular defects of other enzymes in the pathway have been identified, and it seems likely that a complete description of these defects at the molecular level is a realistic goal. In basic biological terms, such studies will lead to a better understanding of the genetic control exerted on this pathway. In clinical terms, they will lead to improved understanding of the molecular pathophysiology of these diseases and may well provide the necessary techniques to proceed with the screening of these disorders.

Fatty Acids↗
PubMed1991

Chronic cardiomyopathy and weakness or acute coma in children with a defect in carnitine uptake.

A defect in intracellular uptake of carnitine has been identified in patients with severe carnitine deficiency. To define the clinical manifestations of this disorder, the presenting features of 15 affected infants and children were examined. Progressive cardiomyopathy, with or without chronic muscle weakness, was the most common presentation (median age of onset, 3 years). Other patients presented with episodes of fasting hypoglycemia during the first 2 years of life before cardiomyopathy had become apparent. A defect in carnitine uptake was demonstrable in fibroblasts and leukocytes from patients. The defect also appears to be expressed in muscle and kidney. Concentrations of plasma carnitine and rates of carnitine uptake in parents were intermediate between affected patients and normal control subjects, consistent with recessive inheritance. Early recognition and treatment with high doses of oral carnitine may be life-saving in this disorder of fatty acid oxidation.

Biological Transport↗
PubMed1991

Familial combined hyperlipidaemia: use of stable isotopes to demonstrate overproduction of very low-density lipoprotein apolipoprotein B by the liver.

We have assessed very low-density lipoprotein apolipoprotein B production, using [15N]glycine as an endogenous marker in a 9-hour primed constant infusion protocol, in four adult male subjects with familial combined hyperlipidaemia and in four normolipidaemic adult male controls. The mean very low-density lipoprotein apolipoprotein B absolute synthetic rate was significantly greater in the familial combined hyperlipidaemic subjects than in control subjects (26.31 +/- 8.37 vs 9.36 +/- 4.07 mg/kg per 24 h, p less than 0.05). These results confirm findings using exogenous radioisotope labelling techniques that very low-density lipoprotein apolipoprotein B production is significantly increased in most patients with familial combined hyperlipidaemia. A modified 9-hour protocol can be safely done repeatedly and in children and pregnant women.

Adult↗
PubMed1991

Immunochemical characterization of variant long-chain acyl-CoA dehydrogenase in cultured fibroblasts from nine patients with long-chain acyl-CoA dehydrogenase deficiency.

Long-chain acyl-CoA dehydrogenase (LCAD) deficiency is a disorder of mitochondrial fatty acid oxidation that is characterized by hypoglycemia, muscle weakness, and hepato- and cardiomegaly. To characterize variant LCAD, we first carried out preliminary experiments using pure enzyme preparations. Despite the significant sequence similarity of LCAD to medium-chain acyl-CoA dehydrogenase, the antibody raised against rat LCAD was monospecific for human and rat LCAD and did not cross-react with either human or rat medium-chain acyl-CoA dehydrogenase. Immunoblot analysis of variant LCAD in cultured fibroblasts from nine patients with LCAD deficiency revealed a single LCAD band in all nine LCAD-deficient cell lines. Each variant LCAD was comparable in molecular size and quantity to normal LCAD, suggesting that the LCAD mutation in each of these cell lines is likely to be a point mutation that produces a stable variant LCAD. The uniform nature of variant LCAD suggests that only a single, or at most a few, prevalent point mutations may be found in the majority of LCAD-deficient patients. If this is the case, it should be possible to devise a molecular diagnostic method for LCAD deficiency.

Acyl-CoA Dehydrogenase↗
PubMed1991

Molecular survey of a prevalent mutation, 985A-to-G transition, and identification of five infrequent mutations in the medium-chain Acyl-CoA dehydrogenase (MCAD) gene in 55 patients with MCAD deficiency.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is an inborn error of fatty-acid oxidation that is characterized by fasting intolerance and recurrent episodes of hypoglycemic coma which can be fatal. Its incidence is one of the highest among genetic metabolic disorders. Using a modified PCR and NcoI digestion method, we have surveyed 46 additional, unrelated MCAD-deficient patients for a prevalent mutation, an 985A-to-G transition (985A----G), that we previously identified in nine MCAD-deficient patients. Among the total of 55 studied, 44 were homozygous and 10 were heterozygous for the 985G allele, whereas one did not carry this mutant allele, indicating that the prevalence of the 985G allele is 89.1%. Furthermore, we identified five other types of mutation: one each in three of the compound heterozygotes and two in the single non-985G patient. An RFLP study of 12 985G-homozygotes showed that all 24 alleles fell into a single haplotype. A questionnaire regarding the ethnic and national origin of their patients was sent to all referring investigators. All 41 patients for whom this information was provided were Caucasians. Of 29 patients whose country of origin was specified, 19 and five were from the British Isles and Germany, respectively. These data suggest that 985A----G may have occurred in a single person in an ancient Germanic tribe.

Acyl-CoA Dehydrogenase↗
PubMed1990

Identification of a common mutation in patients with medium-chain acyl-CoA dehydrogenase deficiency.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is one of the most common recessively inherited metabolic diseases in man. We have studied fibroblast cultures obtained from three patients with MCAD deficiency by sequencing the entire coding region of MCAD mRNA. A single A to G nucleotide replacement which resulted in lysine329-to-glutamic acid329 substitution of the MCAD protein was identified in all cultures. Furthermore, this point mutation was present in 91% (31 of 34) of mutant MCAD alleles, indicating that the majority of cases with MCAD deficiency are caused by this type of mutation.

Acyl-CoA Dehydrogenase↗
PubMed1990

Measurement of (C13)arginine incorporation into apolipoprotein B-100 in very low density lipoproteins and low density lipoproteins in normal subjects using (13C)sodium bicarbonate infusion and isotope ratio mass spectrometry.

We describe a new stable isotope technique for the in vivo study of hepatic plasma protein synthesis in humans. The method involves the infusion of (13C)sodium bicarbonate for 1 h and the measurement of the isotopic enrichment of (13C)arginine in newly synthesized apolipoprotein B of very low density lipoproteins (VLDL-apoB) and low density lipoproteins (LDL-apoB) in blood samples taken over a 5-6 h period from the commencement of the infusion. Isotope ratio mass spectrometry was utilized to measure 13CO2 enrichment following hydrolysis of these proteins and conversion of the guanidinium carbon of arginine in the hydrolysate to carbon dioxide by sequential incubation with arginase and urease. The method is capable of measuring isotopic enrichment as low as 0.001 at.% excess (APE) with a precision of 1.2%. In both subjects studied, the (13C)arginine of VLDL-apoB reached enrichments of 0.2 APE and that of the arginine of LDL-apoB, 0.03 APE. Incorporation of labeled arginine into LDL-apoB was demonstrable at 60-90 min. The new technique is safe and is applicable to the study of the hepatic biosynthesis of a wide range of plasma proteins.

Adult↗
PubMed1990

Analysis of abnormal urinary metabolites in the newborn period in medium-chain acyl-CoA dehydrogenase deficiency.

In order to determine which are useful early diagnostic markers for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, we have analysed urine from an asymptomatic neonate. Profiling of urinary organic acids followed by peak confirmation by electron impact mass spectrometry revealed a high suberate/adipate ratio (greater than 1.0) and the presence of n-hexanoylglycine (HG). Acylcarnitine analysis by fast atom bombardment mass spectrometry (FAB-MS) was inconclusive, but FAB-MS/MS (tandem mass spectrometry) revealed diagnostic amounts of octanoylcarnitine and hexanoylcarnitine. Quantitative analysis of acylglycines by stable isotope dilution and chemical ionization mass spectrometry revealed a 30-fold increase in HG and increased suberylglycine, but no increase in 3-phenylpropionylglycine.

Acyl-CoA Dehydrogenase↗
PubMed1990

Early diagnosis and treatment of neonatal medium-chain acyl-CoA dehydrogenase deficiency: report of two siblings.

Two siblings are reported who were symptomatic in the neonatal period. The first died suddenly at 4 days of age after regurgitating a meal. The postmortem examination showed steatosis of the liver, kidney and muscle. In the second, medium-chain acyl-CoA dehydrogenase (MCAD) deficiency was diagnosed at 3 days of age with muscular hypotonia, vomiting, hyperammonaemia and mild acidosis. Thus disorders of fatty acid oxidation should also be considered in newborns. The biochemical work up indicates that in neonates, analysis of serum medium-chain fatty acids and of acyl and free carnitine are more likely to lead to a diagnosis than determining dicarboxylic acids alone in urine. Long-term treatment was effective and monitored by the acyl/free carnitine ratio.

Acid-Base Equilibrium↗
PubMed1990

Prevalence and expression of familial combined hyperlipidemia in childhood.

The objectives of this study were (1) to determine the incidence of dominantly inherited hyperlipoproteinemia in children referred to our medical center because of hyperlipidemia associated with a family history of premature coronary artery disease and (2) to assess the degree of expression in childhood of the most common inherited hyperlipoproteinemia, familial combined hyperlipidemia. Among 129 families referred to us by area pediatricians, we identified a dominantly inherited hyperlipoproteinemia in 97 of them. Twenty had familial hypercholesterolemia, 65 familial combined hyperlipidemia, 11 hyperapobetalipoproteinemia, and one familial hypertriglyceridemia. As expected, almost half (9/20) of the siblings of probands with familial hypercholesterolemia were affected. Although we expected incomplete gene penetrance in the siblings of the probands with familial combined hyperlipidemia, we found 43 affected and 40 unaffected among the 83 siblings of the 65 probands. Our findings suggest that hyperlipidemia in children, caused by familial combined hyperlipidemia, occurs more than three times as frequently as familial hypercholesterolemia and that in families identified by a child proband, the penetrance is complete. Pediatricians should identify this primary hyperlipidemia in childhood and attempt to prevent the associated risk of premature coronary artery disease by prescribing appropriate diet and life-style modifications.

Adult↗
PubMed1990

Molecular basis of medium chain acyl-coenzyme A dehydrogenase deficiency. An A to G transition at position 985 that causes a lysine-304 to glutamate substitution in the mature protein is the single prevalent mutation.

We sequenced polymerase chain reaction (PCR)-amplified variant medium chain acyl-CoA dehydrogenase (MCAD) cDNAs in cultured fibroblasts from three MCAD-deficient patients. In all three patients, an A to G transition was identified at position 985 of the coding region. Since no appropriate restriction sites for detecting this point mutation were found, we devised a PCR method that amplifies an 87-bp fragment from position 955. In the 5' primer encompassing positions 955 to 984, A-981 was artificially substituted with C. With the presence of C-981 and G-985, an Nco I restriction site is introduced in the mutant copies. When cDNA or genomic DNA from fibroblasts of nine MCAD-deficient patients were tested with this method, the copies from all of them completely cleaved into two shorter fragments by Nco I, indicating their homozygosity for the A----G-985 transition. In contrast, the copies from all eight controls remained intact. Thus, this A----G-985 transition is the single prevalent mutation causing MCAD deficiency, a highly unusual feature for any genetic disorder. The PCR/Nco I digestion method is suitable for the diagnosis of MCAD deficiency.

Acyl-CoA Dehydrogenase↗