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Biomedical subjects

M O Livet

Publications and source records attributed to M O Livet.

At least 37 records · Page 2Linked to original sources
PubMed1998

Angelman syndrome: correlations between epilepsy phenotypes and genotypes.

We compared epilepsy phenotypes with genotypes of Angelman syndrome (AS), including chromosome 15q11-13 deletions (class I), uniparental disomy (class II), methylation imprinting abnormalities (class III), and mutation in the UBE3A gene (class IV). Twenty patients were prospectively selected based on clinical cytogenetic and molecular diagnosis of AS. All patients had 6 to 72 hours of closed-circuit television videotaping and digitized electroencephalogrpahic (EEG) telemetry. Patients from all genotypic classes had characteristic EEGs with diffuse bifrontally dominant high-amplitude 1- to 3-Hz notched or triphasic or polyphasic slow waves, or slow and sharp waves. Class I patients had severe intractable epilepsy, most frequently with atypical absences and myoclonias and less frequently with generalized extensor tonic seizures or flexor spasms. Epileptic spasms were recorded in AS patients as old as 41 years. Aged-matched class II, III, and IV patients had either no epilepsy or drug-responsive mild epilepsy with relatively infrequent atypical absences, myoclonias, or atonic seizures. In conclusion, maternally inherited chromosome 15q11-13 deletions produce severe epilepsy. Loss-of-function UBE3A mutations, uniparental disomy, or methylation imprint abnormalities in AS are associated with relatively mild epilepsy. Involvement of other genes in the chromosome 15q11-13 deletion, such as GABRB3, may explain severe epilepsy in AS.

Adolescent↗
PubMed1997

[Smith-Magenis syndrome].

Smith-Magenis syndrome is caused by a 17p11.2 deletion. It associates mental retardation, facial dysmorphism and brachydactyly; aberrant behavior and major sleep problems are present in 70% of the cases. It is probably under-diagnosed because the facial abnormalities are mild and the behavioral problems with hyperactivity and self-injuries are dominant, leading to the diagnosis of psychiatric pathology. However these behavioral problems are sufficiently characterized to allow the diagnosis of the syndrome and look for a 17p11.2 microdeletion. Otorhinolaryngologic, ophthalmologic, cardiac and renal abnormalities can be associated and their evaluation is necessary. Smith-Magenis syndrome is considered as a contiguous gene syndrome. Genes have been mapped and isolated to the critical region, but their participation in the pathogenesis of the syndrome remains unclear.

Abnormalities, Multiple↗
PubMed1997

Ischemic cerebrovascular disease in children: retrospective study of 35 patients.

A 10-year review of a neuropediatric department experience with childhood ischemic cerebrovascular disease identified 35 patients with arterial ischemic stroke. The ability to diagnose stroke in children has improved with the development of imaging techniques in the past few years. Children have a wide array of risk factors for ischemic strokes, since some are acquired and others are congenital. Twenty-eight associated conditions (80%) were found in our patients and we identified 17 specific causes (48.5%) among them. The cause of stroke in children is important to recognize because stroke is likely to recur depending on the etiology.

Adolescent↗
PubMed1997

[Ophthalmologic signs in children with autism].

PURPOSE: Autism is a clinical entity defined by characteristic association of a lack of social interactions and communications, beginning before three years of age. The purpose of this study was to screen ophthalmologic findings in autistic children. MATERIALS AND METHODS: Ten autistic children, 6 girls and 4 boys, underwent a complete ophthalmologic examination in the Department of Pediatric Ophthalmology at the Hospital La Timone, Marseilles, France. Their age ranged from 1 to 14 years (mean = 8.5 +/- 3.8). RESULTS: Refraction showed hypermetropia in 7 cases (70%), astigmatism more than 1 diopter in 6 cases (60%), bilateral astigmatism in 4 cases (40%) and unilateral astigmatism in 2 cases (20%). Astigmatism axis was oblique for 8 eyes, with the rule for 6 eyes and against the rule for 2 eyes. Strabismus was present in 6 cases (60%) including 4 cases of exotropia. Fundus examination found pallor of the optic disc in 4 cases. CONCLUSION: Ophthalmologic findings in autistic children appear to be mainly unilateral or bilateral astigmatism and binocular vision troubles. They can lead to amblyopia with the risk of functional loss of vision. Early diagnosis of visual problems in autistic children is also essential in order to be able to propose adequate psychological and educational cares for the children and their family.

Adolescent↗
PubMed1996

Cortical myoclonus in Angelman syndrome.

Angelman syndrome (AS) results from lack of genetic contribution from maternal chromosome 15q11-13. This region encompasses three GABAA receptor subunit genes (beta3, alpha5, and gamma3). The characteristic phenotype of AS is severe mental retardation, ataxic gait, tremulousness, and jerky movements. We studied the movement disorder in 11 AS patients, aged 3 to 28 years. Two patients had paternal uniparental disomy for chromosome 15, 8 had a >3 Mb deletion, and 1 had a microdeletion involving loci D15S10, D15S113, and GABRB3. All patients exhibited quasicontinuous rhythmic myoclonus mainly involving hands and face, accompanied by rhythmic 5- to 10-Hz electroencephalographic (EEG) activity. Electromyographic bursts lasted 35 +/- 13 msec and had a frequency of 11 +/- 2.4 Hz. Burst-locked EEG averaging in 5 patients, generated a premyoclonus transient preceding the burst by 19 +/- 5 msec. A cortical spread pattern of myoclonic cortical activity was observed. Seven patients also demonstrated myoclonic seizures. No giant somatosensory evoked potentials or C-reflex were observed. The silent period following motor evoked potentials was shortened by 70%, indicating motor cortex hyperexcitability. Treatment with piracetam in 5 patients significantly improved myoclonus. We conclude that spontaneous, rhythmic, fast-bursting cortical myoclonus is a prominent feature of AS.

Adolescent↗
PubMed1996

Early clinical and EEG features of infantile spasms in Down syndrome.

The combination of West syndrome (WS) and Down syndrome appears not to be coincidental. Fourteen patients free of cardiac malformation or history of perinatal hypoxia were referred and investigated before they had received any treatment and were followed to the mean age of 4.5 years (range 19 months to 14 years). Spasms had onset at the mean age of 8 months (range 4-18 months) in cluster and were symmetrical. Hypsarrhythmia was symmetrical and, after intravenous diazepam (4 patients, 0.5 mg/kg) it disappeared, without any remaining focus. Recorded spasms during a cluster were "independent," with recurrence of hypsarrhythmia between successive spasms, and thus had the ictal and interictal EEG characteristics of idiopathic WS. Seven patients exhibited other types of seizures after WS, consisting of myoclonic jerks, atonic, tonic-clonic or absence seizures, which proved quite easy to control with valproate and/or ethosuximide.

Adolescent↗
PubMed1994

[Angelman syndrome].

The Angelman syndrome is a neurological disorder characterized by constant features: severe mental retardation, easily provoked laughter, ataxia, absent speech, seizures. Most cases are sporadic but familial cases have been reported. About 60 to 70% of cases are due to an interstitial deletion on the maternally inherited chromosome 15 in the region q11-q13. Rare cases result from paternal disomy. In 30% of patients, neither maternal by inherited deletion, nor paternal disomy, can be found. In this category of patients recurrence risk for sibs is high and molecular mechanisms are not completely known. They appear to be more complex than previously suggested. It is clear that this syndrome is a genetically heterogeneous group. The main example of genomic imprinting in human pathology, Angelman syndrome is now a model in research for understanding molecular mechanisms underlying imprinting.

Angelman Syndrome↗
PubMed1992

Neurological findings and seizure outcome in children with bilateral opercular macrogyric-like changes detected by MRI.

The authors studied 10 patients aged between six and 23 years (mean age 14 years 5 months) with magnetic resonance imaging, which detected bilateral 'macrogyric-like' maldevelopment of the insulo-opercular regions. The data confirm that biopercular gyral anomaly, associated with mental retardation, pseudobulbar palsy (cortical or central) and epilepsy, represents an anatomo-clinical syndrome. Nevertheless, a wide clinical spectrum was found varying from pictures correlating with the topography and extent of the MRI-detected anomaly to conditions indicating wider cerebral involvement. Epilepsy, varying greatly in age at onset and severity, consistently influenced the prognosis for five patients with diffuse EEG abnormalities and intractable seizures with falls. Anterior callosotomy relieved such seizures in one case.

Adolescent↗
PubMed1992

Epilepsy and focal gyral anomalies detected by MRI: electroclinico-morphological correlations and follow-up.

The authors studied 10 patients (mean age 15 years 6 months) with localized developmental gyral disorder detected by MRI. There were two groups of major malformations. Seven patients (group 1) had unilateral 'macrogyric-like' insulo-opercular changes, one of whom died early in life and had extensive microgyria. The six others had mental retardation and epilepsy, three of whom had focal neurological signs. Age at onset of epilepsy varied greatly. Clinical and EEG data suggested a wider cerebral involvement than recognized on MRI. The remaining three patients (group 2) had abnormal gyri of variable topography and extension, with bulging grey matter and ventricular deformity. One had mental retardation, another had neurological signs. All had intractable complex partial seizures and focal EEG anomalies correlating with the MRI lesion site, pointing to a well-defined epileptogenic zone. No clinical or EEG evidence of significant malformation in the remaining brain tissue was observed. Ablative surgery was beneficial for one patient; focal cortical dysplasia was the pathological substrate.

Adolescent↗
PubMed1992

[Spinal cord tumor with meningeal invasiveness revealed by intracranial hypertension syndrome].

The association of hydrocephalus and intramedullary spinal-cord tumor with leptomeningeal spread is described in a 20 month-old boy. The pathogenesis of increased intracranial pressure in spinal cord tumor is discussed. Meningeal gliomatosis is rare and is more often observed in the follow-up of cerebral gliomas. It exceptionally occurs in patients without known cerebral or spinal tumor. Such a tumor often occurs in young patients and has a poor prognosis.

Glioma↗
PubMed1991

Smith-Magenis syndrome: a new contiguous gene syndrome. Report of three new cases.

Interstitial deletion of the short arm of chromosome 17 was detected in three patients. They all had a similar phenotype with mental retardation, behavioural problems, facial dysmorphism, brachycephaly, a broad face with a flat midface, and short and broad hands. All three cases were ascertained over a six month period by two neuropaediatricians aware of this specific anomaly, which suggests that this microdeletion is not particularly rare. Comparison of the clinical and cytogenetic findings in a total of 24 patients allows a new contiguous gene syndrome to be defined that only high resolution analysis can detect. In two cases, molecular analysis confirmed the cytogenetic results. The Charcot-Marie-Tooth type Ia gene has recently been localised to the 17p11.2 sub-band.

Abnormalities, Multiple↗
PubMed1991

[Outcome of herpetic encephalitis. Apropos of 10 cases].

Ten cases of herpetic encephalitis in children aged 2 months to 13 1/2 years at onset are reviewed retrospectively. There were four infants and six children 3 to 13 1/2 years old. Diagnosis was established on the basis of widely accepted electroclincal and neuroradiological criteria. Biologic confirmation was obtained in only half the cases. Two patients died during the initial episode. One patient was lost to follow-up two months after the first episode. Follow-ups ranged from 2 to 10 years for the seven remaining patients. Epilepsy and neurodevelopmental impairment occurred in a significant number of cases (5/7 and 6/7 respectively). Two patients had two episodes and one had more than two episodes of encephalitis. This poor outcome is discussed, as well as possible explanations for recurrent disease and particular neuropsychologic patterns, including Kluver-Bucy syndrome seen in two patients of this series.

Adolescent↗
PubMed1989

Indications of radiological explorations in partial epilepsy of childhood.

In partial epilepsy of childhood the decision to request radiological exploration rests on a good knowledge of the disease. The authors summarize the electrical and clinical features of the various types of partial epilepsy. Most of these types, and in particular benign partial epilepsy with rolandic paroxysms, require no exploration. In contrast, symptomatic partial epilepsy must be investigated in search of a brain lesion. In such cases CT is indispensable. The more accurate and more sensitive MRI may be performed either initially or after a negative CT scanning in children with partial epilepsy which does not respond to medical treatment.

Child↗
PubMed1985

Radiology of ischemic strokes in children.

Arterial ischemic strokes are a relatively frequent diagnostic occurrence in pediatric neuroradiology. They occur mostly in three main etiologic contexts: congenital heart disease; neonatal distress; infections, focal or general inducing vasculitis, but many cases are considered idiopathic. The positive diagnosis is made by CT; in neonates, however, ultrasound appears as a promising tool. The CT features are basically similar at that age and in adults, although the site of the infarct may result from pathologies more particular to children (e.g. basal ganglia infarction due to arteritis of the carotid siphon and its branches). Infarcts may be multiple and also more frequently hemorrhagic at that age, the hemorrhagic phenomena affecting only the gray matter except in young infants in which the subcortical white matter may be affected also. Anatomical sequels include focal atrophy and asymmetry of the brain. Data regarding the etiology can be gathered from angiography which may show the degree of impairment of the arterial bed, its extent, the collateral blood supply and the morphological type of arterial lesion responsible for the cerebral damage. The most particular picture at that age is that of the often diffuse vasculitis, with its various expressions (segmental narrowing of the lumen, dissecting aneurysm, string-of beads appearance).

Brain Damage, Chronic↗
PubMed1981

Melanocytic involvement in giant axonal neuropathy.

The skin of a patient with giant axonal neuropathy was studied by light and electron microscopy. Enlarged melanocytes protruded into the papillary dermis. An increased number of microfilaments (100 A), which accumulated in rounded or irregular clusters was the main pathological feature. Melanosomes and melanisation were normal. A similar increase of microfilaments was seen in axons and Schwann cells of peripheral nerves, fibroblasts and endothelial cells. This suggests that this metabolic, probably inborn and genetic disorder, does not only affect the nervous system but also the whole microfilament system (cytoskeleton).

Axons↗