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C Dorche

Publications and source records attributed to C Dorche.

At least 37 records · Page 2Linked to original sources
PubMed1991

Infantile isolated sulphite oxidase deficiency: report of a case with negative sulphite test and normal sulphate excretion.

We present the clinical and biochemical data of a patient with infantile isolated sulphite oxidase deficiency with late onset of symptoms. A comparison of the biochemical parameters is made with the neonatal type of this disease and with the data of described patients with the combined defect of sulphite oxidase and xanthine oxidase, due to molybdenum cofactor deficiency. False-negative sulphite dip stick test as a pitfall in the diagnosis of sulphite oxidase deficiency is discussed.

Humans↗
PubMed1990

Studies on the interaction of a thiol-dependent hydrogen peroxide scavenging enzyme and phenylalanine hydroxylase.

Rat liver phenylalanine hydroxylase is irreversibly inactivated by a H2O2-dependent process. Since H2O2 can be produced by autooxidation of the tetrahydropterin cofactor required for the hydroxylation reaction, in vitro assays are usually carried out in the presence of added catalase. On the basis of a dithiothreitol-dependent protecting assay of phenylalanine hydroxylase, carried out in the absence of catalase, we have isolated an enzyme fraction from neonatal rat livers which has similar properties to the known enzyme, glutathione peroxidase. The developmental time course for phenylalanine hydroxylase in rats has been reported to follow two different patterns. Using the dithiothreitol assay, McGee et al. (1972, Biochem. J. 127, 669-674) have found that newborn rats have low phenylalanine hydroxylase activity which increases to adult levels over several months. On the other hand, using catalase-supplemented assays, others have found that newborn rats have nearly adult levels of phenylalanine hydroxylase activity. The protective effect of glutathione peroxidase on phenylalanine hydroxylase suggests that the developmental time course found by McGee et al. may represent the slow developmental time course previously found for glutathione peroxidase. In addition, feeding rats a selenium-deficient diet, which reduces the hepatic activity of the selenium-containing glutathione peroxidase, results in a concomitant irreversible loss of phenylalanine hydroxylase activity, suggesting that glutathione peroxidase may play a vital role in protecting phenylalanine hydroxylase in vivo from peroxide inactivation.

Animals↗
PubMed1988

Neonatal hyperphenylalaninaemia presumably caused by a new variant of biopterin synthetase deficiency.

Systematic investigation of hyperphenylalaninaemic infants for tetrahydrobiopterin deficiency has recently led to the description of new variants of cofactor deficiency. In the present case, the initial observation was of hyperphenylalaninaemia with a significant increase in the neopterin to biopterin ratio in the urine. A tetrahydrobiopterin loading test resulted in a significant decrease of blood phenylalanine levels. Cerebrospinal fluid (CSF) biopterin and neurotransmitter metabolite levels were within the normal range. The in vivo clearance of phenylalanine remained altered despite a high dietary tolerance. At 9 months of age, the patient was clinically well, but minor neurological signs appeared when blood phenylalanine levels increased. These data were similar to those found in the so-called "peripheral form" of tetrahydrobiopterin deficiency. However, an unidentified pteridine-like compound had been found in the urine and CSF since the birth, suggesting the existence of an unknown block in the biosynthetic pathway of biopterin.

Biogenic Amines↗
PubMed1988

Worldwide experience in newborn screening for classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

The need for a reliable screening test for classical congenital adrenal hyperplasia prompted development of newborn screening programs. Worldwide incidence of classical congenital adrenal hyperplasia in this report was taken from newborn screening programs in France, Italy, Japan, New Zealand, Scotland, and the United States. Two populations in which the occurrence of congenital adrenal hyperplasia among live births has been reported with greater than usual frequency are the Yupik Eskimos of southwestern Alaska (1:282) and the people of La Reunion, France (1:2,141). Aside from these populations, 1,093,310 newborns were screened between 1980 and 1988, of whom 77 had congenital adrenal hyperplasia. Thus, worldwide incidence of this disorder was estimated at 1:14,199 live births for homozygous patients, 1:60 for heterozygous subjects, with a gene frequency of 0.0083. Incidence of congenital adrenal hyperplasia among whites was estimated to be 1:11,909 (41:488,279) for homozygous patients, 1:55 for heterozygous subjects with a gene frequency of 0.0091. Incidence for the salt-wasting form of congenital adrenal hyperplasia was 1:18,850 (58:1,093,310) compared with 1:57,543 (19:1,093,310) for congenital adrenal hyperplasia in the simple virilizing form. Thus, salt-wasting congenital adrenal hyperplasia was three times more common than simple virilizing congenital adrenal hyperplasia. Estimated incidence of congenital adrenal hyperplasia in white populations in Italy and France (1:10,866) was higher than in Scotland (1:17,098), New Zealand (1:14,500). The incidence in an Asian population (Japan) (1:15,800) did not differ significantly from that of the white population. In four of five populations, overall incidence was higher than previously reported, as was the frequency of the salt-wasting form (75% v 50% to 66%), suggesting improved case detection by newborn screening.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1987

[Systematic neonatal detection of Duchenne's muscular dystrophy. Results after 10 years' of experience in Lyons (France)].

Neonatal screening of Duchenne Muscular Dystrophy using serum CK level measurement has been performed for 10 years in a part of the Rhône-Alpes area (40,000 newborns per year). This test avoids consecutive cases in an affected family by mean of an early genetic counselling. So, 10 potential DMD boys have been avoided (i.e. one out of five of the D.M.D., as a whole which would be born during this same ten year study). Details on familial structures and efficiency of genetic counselling are given, and this efficiency will be increased by the DNA study of the concerned families.

Creatine Kinase↗
PubMed1979

[Systematic neonatal screening for Duchenne muscular dystrophy].

More than 15% of cases of Duchenne muscular dystrophy (DMD) may be preventable by the neonatal diagnosis of another affected relative. Systematic neonatal screening seems a more efficient way of getting information for genetic counseling. The principle of the test described is the detection of a specific increase of the activity of Creatine-Kinase (CK) in the blood of newborn children with myopathy. Blood may be spotted on paper and posted to a central laboratory. Furthermore this program can be integrated into the systematic screening of phenylketonurie. The specificity and accuracy of the bioluminescent reaction used for the evaluation of CK suggest that this screening reaction is reliable. A systematic neonatal screening program for DMD such as ours in the Rhône-Alpes area (France) will lead to frequent recourse to prenatal diagnosis now possible through sex fetal determination and which would be possible through in utero blood sampling.

Creatine Kinase↗
PubMed1978

[Familial congenital muscular dystrophy caused by phosphofructokinase deficiency].

Two children, born to related parents, presented since birth a muscular defect rapidly complicated by painful joint stiffness. The oldest child died at 6 months of age, from respiratory complications. The second-14 month old- does not sit without support. The muscle fibres are of unequal calibre and numerous fibres have under-sarcolemmal PAS positive areas contain glycogen, as seen on electron microscopy. In the second patient, the biochemical analysis showed a moderate glycogen accumulation and muscular enzymatic studies demonstrated an isolated and major deficiency in phosphofructokinase activity. Activity was normal in red blood cells and in fibroblasts cultured in vitro. Hence, these cases should be distinguished from formerly reported cases of phosphofructokinase deficiency. This type of P.F.K. deficiency should be looked for in patients with severe congenital muscular dystrophy and early joint involvement.

Erythrocytes↗