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N Guffon

Publications and source records attributed to N Guffon.

25 records · Page 2Linked to original sources
PubMed1996

Molecular histology of mitochondrial and nuclear transcripts in the muscle of patients harbouring a single mitochondrial DNA deletion.

The distribution of transcripts of mitochondrial and nuclear genes involved in oxidative phosphorylation and of the mitochondrial creatine kinase nuclear gene was examined, using in situ hybridisation, in the skeletal muscle of 11 patients harbouring a heteroplasmic mitochondrial DNA (mtDNA) single deletion. Levels of mRNAs transcribed from genes located within the deletions were not decreased, suggesting that the remaining wild-type mtDNA was still transcribed. Those muscle fibres with characteristic abnormal mitochondrial proliferation always showed overexpression of mRNAs and rRNAs transcribed from mitochondrial genes located outside the deletions. Interestingly, they also showed overexpression of the nuclear-encoded ATP synthase beta subunit mRNA, but not of mitochondrial creatine kinase mRNA. These observations lead to three proposals: (1) overexpression of mitochondrial transcripts within fibres harbouring mitochondrial proliferation, together with the apparently normal expression of the remaining wild-type mtDNA, is not related to decreased mitochondrial translation; (2) it is more probably related to an up-regulation mechanism which co-ordinates both mitochondrial and nuclear expression; and (3) this mechanism is restricted to transcripts directly involved in oxidative phosphorylation and to fibres with mitochondrial accumulation.

Adolescent↗
PubMed1995

A new neonatal case of N-acetylglutamate synthase deficiency treated by carbamylglutamate.

N-Acetylglutamate synthase (NAGS) deficiency is a rare, autosomal recessive urea-cycle disease. Its clinical presentation is not different from the other hereditary hyperammonaemias. We report a new neonatal case with hyperammonaemic coma. A test by carbamylglutamate was performed at 25 days of life. Since then, the child was treated by carbamylglutamate three or four times a day with a total dose of 80-100 mg/kg per day. Today, the boy is 1 year old. He receives carbamylglutamate 200 mg four times a day. He has normal somatic and neurological development and good metabolic balance.

Acetyltransferases↗
PubMed1993

2-Ketoglutarate dehydrogenase deficiency, a rare cause of primary hyperlactataemia: report of a new case.

Two new familial cases of 2-ketoglutarate dehydrogenase (2-KGD) deficiency are reported: a girl who died at 10 years and a boy, still alive at 4 years, born to consanguineous parents. The cases developed progressively severe encephalopathy with axial hypotonia, psychotic behaviour, pyramidal symptoms and failure to thrive. Both children exhibited permanent lactic acidosis with acute episodes during emotional stress and various infections, associated with elevated lactate/pyruvate (L/P) ratio and slightly decreased ketone body ratio in plasma. In fibroblasts, the L/P ratio was greatly increased in the boy. No respiratory chain complex deficiency could be demonstrated in cultured fibroblasts or in mitochondria isolated from a muscle biopsy performed on the boy. In muscle isolated mitochondria, a progressive decrease of the rate of glutamate oxidation was observed after ADP addition; the rate of 2-ketoglutarate oxidation was low in the absence of ADP and did not increase after ADP addition. 2-KGD deficiency was demonstrated in fibroblasts from both children and in the boy's muscle and myoblasts. The 2-KGD complex is composed of three separate enzymes: E1, E2 and E3. We could demonstrate in our patient that the E1 and E3 subunits were normal, suggesting that the E2 component could be responsible for the defect.

Acidosis, Lactic↗
PubMed1993

[Multiple acyl-CoA dehydrogenase deficiency. Report of 2 siblings].

The authors report on two siblings with a multiple acyl-CoA dehydrogenase deficiency. The first child died from a Reye's syndrome when he was 9 month-old. The diagnosis was made in the neonatal period in his brother. Early treatment with glucose and carnitine should prevent acute attacks.

Acyl-CoA Dehydrogenases↗
PubMed1993

[Dietary treatment of maple syrup urine diseases].

Principles of dietary management and needs in maple syrup urine disease are well defined. However, long-term results show that there is a need for an improvement of the maintenance of a low plasma leucine level and in monitoring episodes of metabolic decompensation in order to ameliorate the survival and psycho-intellectual outcome.

Adolescent↗
PubMedDate not supplied

Attenuated type I mucopolysaccharidosis in the differential diagnosis of juvenile idiopathic arthritis: a series of 13 patients with Scheie syndrome.

OBJECTIVE: Mucopolysaccharidosis type I (MPS I) is a genetic lysosomal storage disorder caused by deficient activity of the enzyme alpha-L-iduronidase. Incomplete breakdown of glycosaminoglycans leads to progressive accumulation of these substances in many tissues throughout the body. Patients with the less severe form of MPS I (Scheie syndrome) usually present in the first decade of life with frequent articular involvement, and may survive into adulthood. Especially in these attenuated phenotypes, a definitive diagnosis may be delayed for years because clusters of early symptoms are difficult to recognize for physicians not familiar with the disease, and since the disease progresses slowly over decades. We would like to increase the awareness of this type of MPS I disease among rheumatologists and unravel diagnostic pitfalls. METHODS: We have reviewed medical histories of 13 patients (6 males and 7 females) with Scheie syndrome seen in 5 European centers. RESULTS: All patients had prominent musculoskeletal involvement at the onset of their disease in childhood. Diagnosis was delayed in almost all cases (range 4-54 years). CONCLUSION: We suggest that patients who present with progressive non-inflammatory joint involvement in the first decade of life, particularly with stiffness of the fingers and difficulty using the hands, should be screened for metabolic diseases, including MPS I. MPS I should be considered if patients with arthropathy lack the typical characteristics of inflammatory arthropathy.

Arthritis, Juvenile↗