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Biomedical subjects

R Ouvrier

Publications and source records attributed to R Ouvrier.

At least 19 recordsLinked to original sources
PubMed2006

Lesch-Nyhan disease in a 20-year- old man incorrectly described as developing 'cerebral palsy' after general anaesthesia in infancy.

Lesch-Nyhan disease (LND) is a rare X-linked recessive genetic disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. The classic clinical condition is characterized by cognitive impairment, hypotonia at rest, choreoathetosis, hyperuricaemia and the hallmark symptom of severe and involuntary self-mutilation. We describe a man with LND who was initially thought to have suffered from a dyskinetic cerebral palsy after an uncomplicated inguinal herniorrhaphy under general anaesthesia at 5 1/2 months of age. In the absence of overt self-injurious behaviour, the diagnosis was not considered for nearly two decades. The diagnosis of LND was established at 20 years of age through clinical review, biochemical examinations and molecular analysis. HPRT haemolysate activity was 7.6% of the normal control, suggesting that he had a milder variant of the disease. Mutation analysis of the HPRT gene revealed a novel missense mutation, c.449T > G in exon 6 (p.V150G). Cascade testing of family members revealed that the mother was heterozygous for the mutation but two siblings (a brother and a sister) did not carry the sequence mutation. Whether the onset of neurological abnormalities in this particular case can be attributed to the general anaesthesia is discussed.

Adult↗
PubMed2002

The Australian Childhood Dementia Study.

OBJECTIVES: To estimate the prevalence of childhood dementia, identify aetiological factors, and provide a brief survey of the psychosocial impact of childhood dementia. METHOD: The Australian Paediatric Surveillance Unit (APSU) was used to identify children with dementia. A total of 224 cases were notified about the dementia study and 141 (63%) questionnaires were completed and returned. Ascertainment was restricted to those most likely to have progressive neurocognitive decline because of practitioner bias against reporting non-progressive cases as dementia. RESULTS: Eighty children with dementia were identified. The estimated prevalence for dementia in childhood in Australian was 5.6/100,000. Thirteen cases (16%) were notified before the age of two years. Seventeen (21%) children were reported to have uncertain or unknown aetiology. Impact upon day to day family functioning was reported by clinicians to be 'marked' or 'extreme' in 50 (63%) families. Only four (6%) clinicians judged present services to be 'very adequate', while 16 (20%) clinicians judged current psychological support for the needs of the family to be 'very' or 'moderately inadequate'. Dementia as an overarching diagnostic concept offers integrative possibilities for research, management and service planning and provision. Childhood disintegrative disorder as a concept is criticised.

Adolescent↗
PubMed2001

Severe infantile axonal neuropathy with respiratory failure.

We describe 5 infants (4 male, 1 female) with a severe intractable form of motor-sensory axonal neuropathy. All became ventilator-dependent, 4 have since died and 1 remains static. Diaphragmatic paralysis was an early feature with generalized neuropathy evolving rapidly. Nerve conduction studies and biopsies were consistent with axonal disease. This disorder could be a new condition or part of the spectrum of inherited neuropathies of the axonal degenerative type. It may be that there is a "switching-off" in the infant's Schwann cell-axonal interactions in utero or in the early postnatal period, resulting in severe progressive deterioration and then a static period without recovery.

Biopsy↗
PubMed2001

Mutations in the gene encoding immunoglobulin mu-binding protein 2 cause spinal muscular atrophy with respiratory distress type 1.

Classic spinal muscular atrophy (SMA) is caused by mutations in the telomeric copy of SMN1. Its product is involved in various cellular processes, including cytoplasmic assembly of spliceosomal small nuclear ribonucleoproteins, pre-mRNA processing and activation of transcription. Spinal muscular atrophy with respiratory distress (SMARD) is clinically and genetically distinct from SMA. Here we demonstrate that SMARD type 1 (SMARD1) results from mutations in the gene encoding immunoglobulin micro-binding protein 2 (IGHMBP2; on chromosome 11q13.2-q13.4). In six SMARD1 families, we detected three recessive missense mutations (exons 5, 11 and 12), two nonsense mutations (exons 2 and 5), one frameshift deletion (exon 5) and one splice donor-site mutation (intron 13). Mutations in mouse Ighmbp2 (ref. 14) have been shown to be responsible for spinal muscular atrophy in the neuromuscular degeneration (nmd) mouse, whose phenotype resembles the SMARD1 phenotype. Like the SMN1 product, IGHMBP2 colocalizes with the RNA-processing machinery in both the cytoplasm and the nucleus. Our results show that IGHMBP2 is the second gene found to be defective in spinal muscular atrophy, and indicate that IGHMBP2 and SMN share common functions important for motor neuron maintenance and integrity in mammals.

Amino Acid Sequence↗
PubMed1999

SYSTEMS: School-Years Screening Test for the Evaluation of Mental Status.

This paper introduces the School-Years Screening Test for Evaluation of Mental Status (SYSTEMS). It was designed to be used by neurologists, pediatricians, and other health professionals assessing children with suspected cognitive problems or changes. SYSTEMS was initially based on the adult Mini-Mental State Examination developed by Folstein, Folstein, and McHugh in 1975. SYSTEMS is a 7- to 12-minute, one-on-one interview test containing 46 items for use in children between 5 and 12 years of age. Although a full diagnosis cannot be made, the results do provide an indication of whether to send a child for further detailed cognitive assessment. The development of SYSTEMS comprised seven studies with a total of 1207 children involved from Sydney primary schools and neurology clinics of the New Children's Hospital, Westmead, New South Wales, Australia. All children were administered the SYSTEMS. Some of the children also were administered the Stanford-Binet Intelligence Test, 4th edition, or the Differential Ability Scales. Results showed that the SYSTEMS was internally consistent, unbiased by sex, socioeconomic indicators, or language groups; discriminated well by age; and strongly correlated (r = 0.88) with mental age. No significant differences in results obtained by two trained administrators were evident and no indication of apparent practice effect was found. The SYSTEMS was found to have desirable levels of sensitivity (83% and 92%), specificity (76% and 95%), and likelihood ratio for cognitive impairment (3.63 and 17.5) when compared with neurologic judgments and the Differential Ability Scales, respectively.

Child↗
PubMed1997

Severe cervical dysplasia and nasal cartilage calcification following prenatal warfarin exposure.

We present an infant who was exposed to warfarin throughout pregnancy and has warfarin embryopathy. When the child was examined radiologically at 20 months areas of calcification were visible in the septal and alar cartilages of the small external part of the nose. The location of this ectopic calcification is consistent with that seen in an animal model of the warfarin embryopathy. It supports the hypothesis that warfarin interferes with the prenatal growth of the cartilaginous nasal septum by inhibiting the normal formation of a vitamin K-dependent protein that prevents calcification of cartilage. The child also had severe abnormalities of the cervical vertebrae and secondary damage to the spinal cord. Cervical vertebral anomalies are a relatively common finding in the warfarin embryopathy and in the related Binder syndrome.

Adolescent↗
PubMed1996

A novel homozygous mutation of the myelin Po gene producing Dejerine-Sottas disease (hereditary motor and sensory neuropathy type III).

We have previously reported that heterozygosity for myelin Po gene mutations were associated with Charcot-Marie-Tooth disease type 1B (CMT1B) or Dejerine-Sottas disease. We investigated the Po gene in a family with clinical Dejerine-Sottas disease and found two children were homozygous for a deletion of Phe 64. The parents were heterozygous first cousins with subclinical CMT1B and slow nerve conduction velocities. These results suggest that the effect of homozygous Phe 64 deletion on impairment of myelination is dosage-dependent. Clinical phenotype and/or myelin impairment may be determined both by the type of mutation and by the dosage of mutated gene.

Base Sequence↗
PubMed1996

Viral encephalitis in children.

Knowledge about the role of viruses in encephalitis and other diseases of the central nervous system has been greatly expanded since the advent of polymerase chain reaction testing. It is known that the spectrum of disease caused by herpes simplex virus, for example, is much wider than was previously recognized. Evidence is mounting that infectious agents may have a causative role in diseases such as recurrent febrile seizures and Rasmussen encephalitis. This review examines the recent advances in treating viral encephalitis and puts these developments into perspective.

Child↗
PubMed1996

Correlation between the histopathologic, genotypic, and phenotypic features of hereditary peripheral neuropathies in childhood.

In recent years, there have been remarkable advances in the understanding of the molecular genetic basis of the hereditary polyneuropathies. Linkage of the genes for Charcot-Marie-Tooth disease to chromosomes 1 and then 17 was followed by the discovery that the commonest form of Charcot-Marie-Tooth disease (CMT1A) was due to a duplication of DNA at 17p11.2-12. This duplication was shown to contain the gene for peripheral myelin protein PMP22. The finding that mutations of the myelin protein PMP22 gene were present in some Charcot-Marie-Tooth disease cases lacking the duplication confirmed the myelin protein PMP22 gene as the site of the defect in Charcot-Marie-Tooth disease. Similarly, defects of the myelin protein P0 gene on chromosome 1 have been demonstrated in a rarer form of Charcot-Marie-Tooth disease (CMT1B). A deletion of DNA at 17p11.2-12 results in the disorder hereditary neuropathy with liability to pressure palsies. Other mutations of the myelin protein PMP22 and myelin protein P0 genes have been associated with the clinical syndrome known as Dejerine-Sottas disease. An X-linked form of Charcot-Marie-Tooth disease (CMTX) has been characterized and shown to be due to mutations of the gap junction protein, connexin 32. Transgenic murine models with inactivated myelin protein PMP22 and myelin protein P0 genes have shown pathologic changes strinkingly similar to those seen in human patients with disturbances of those genes. In this paper, the clinical and histopathologic characteristics of these conditions are discussed in relation to the genotypic basis. It will be argued that there is still an important place for the clinician and nerve pathologist in a medical world immersed in the wonders of molecular genetics.

Adolescent↗
PubMed1993

Hemiplegia due to posterior cerebral artery occlusion.

BACKGROUND: Hemiplegia is a rare manifestation of posterior cerebral artery occlusion. The acute clinical picture may be difficult to differentiate from occlusion of the middle cerebral artery. A mechanism for the hemiplegia has not been conclusively determined. CASE DESCRIPTION: We describe a patient with hemiplegia secondary to posterior cerebral artery occlusion by an embolized fragment of a prosthetic valve. Computed tomographic scan showed the foreign body just distal to the origin of the posterior cerebral artery with infarction of its vascular territory. These findings were later confirmed at autopsy. There was no radiological or autopsy evidence of involvement of the other cerebral arteries or their territories. CONCLUSIONS: The patient provides further evidence that occlusion of the posterior cerebral artery just distal to its junction with the posterior communicating artery may produce contralateral hemiplegia without oculomotor nerve nucleus involvement.

Adolescent↗