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Biomedical subjects

R Gouider

Publications and source records attributed to R Gouider.

At least 37 records · Page 2Linked to original sources
PubMed1997

Charcot-Marie-Tooth disease type 1A with 17p11.2 duplication. Clinical and electrophysiological phenotype study and factors influencing disease severity in 119 cases.

A clinical and electrophysiological study was performed in 119 Type 1A Charcot-Marie-Tooth disease (CMT1A) patients with proven 17p11.2 duplication. Onset of the first functional manifestations was in the first decade in 50% of cases and before the age of 20 years in 70% of cases. The predominant clinical signs were muscle weakness and wasting in the lower limbs. None of the patients was normal on clinical examination and all presented at least pes cavus or ankle jerk areflexia. Motor nerve conduction velocity (MNCV) was uniformly reduced in all nerves, and was < or = 33 m/s in the median nerve for all patients. Sensory potentials were abnormal in all cases, even where there was no clinical sensory loss. Needle electromyography recruitment was reduced in distal muscles for all patients. MNCV slowing was fully consistent with the presence of duplication even in clinically asymptomatic individuals or in children, confirming the complete electrophysiological penetrance of 17p11.2 duplication and making median nerve MNCV a reliable tool for screening affected at-risk individuals. Functional disability was mild. Ninety-six percent of patients were autonomous; 25% were asymptomatic and diagnosed by systematic family investigation especially on the basis of median nerve MNCV reduction. Early age at onset and greatly reduced median nerve MNCV were predictive of a more severe disease course; the earlier the onset the more reduced the median nerve MNCV and the higher the functional disability tended to be after an equivalent disease duration. Cross-sectional analysis of neurological deficit, functional deficit and MNCV according to disease duration showed that, regardless of age at onset, CMT1A disease with 17p11.2 duplication is a clinically progressive disorder. Neurological deficit and functional disability increased, whereas median nerve MNCV and compound muscle action potential (CMAP) amplitude did not change with disease course. Intrafamilial phenotype variation between parents and children and between siblings was studied in large families. Functional disability and neurological deficit differed widely and the highest range of median nerve MNCV within a family reached 23 m/s. Clinical and electrophysiological data were compared with those of CMT1B patients with peripheral myelin P0 protein point mutation. CMT1A patients were found to be more severely affected with more prolonged distal motor latency and more reduced CMAP amplitude, whereas MNCV did not significantly differ, indicating that peripheral myelin P0 protein point mutation is not always associated with a severe phenotype. The same genetic defect (17p11.2 duplication) results in variable expression within the phenotype, even in siblings with variations in age at onset, clinical severity and MNCV slowing. This phenotypic variation could be due to additional genetic factors related to peripheral myelin protein 22 expression as well as to other endogenous or environmental factors.

Adolescent↗
PubMed1997

Hereditary thermosensitive neuropathy: an autosomal dominant disorder of the peripheral nervous system.

We report the clinical and electrophysiologic characteristics of eight patients (four men and four women) with a hereditary neuropathy with probable thermosensitivity (HTN) of autosomal dominant inheritance. Patients presented reversible episodes of ascending muscle weakness, paresthesiae, and areflexia apparently triggered by an elevation of body temperature over 38.5 degrees C. Mean age at onset was 13 +/- 12 (SD; range 6 to 43). Four patients had suffered up to five attacks. EMG and pathologic findings were compatible with a reversible demyelinating neuropathy such as Guillain-Barré syndrome. We excluded loci causing other hereditary demyelinating neuropathies, such as Charcot-Marie-Tooth disease type I (CMT type I) and hereditary neuropathy with liability to pressure palsies (HNPP), by linkage analysis; thus, HTN is not allelic to either CMT type I or to HNPP.

Adult↗
PubMed1997

[Charcot-Marie-Tooth disease: electromyography is still useful in diagnosis and classification].

Genetic heterogeneity was known for a long time in Charcot-Marie-Tooth disease (CMT). The recent findings in molecular biology emphasized the distinction in different types of the disease. Nevertheless, electrophysiological examinations are of a great interest to detect asymptomatic patients, to classify the different forms and to make correlations with the clinical and histological features. Current classification is based on genetic and electrophysiologic data. CMT1, or hypertrophic form in which mutations or a duplication were found on chromosome 17 is the most frequent (CMT1A), CMT2 is the neuronal form, CMT3 is termed the Dejerine-Sottas disease, CMT4 recessive forms, CMT5 a form with associated pyramidal features, and CMTX. The electrophysiologic aspects of these different types are reported.

Charcot-Marie-Tooth Disease↗
PubMed1996

Molecular genetic analysis of the 17p11.2 region in patients with hereditary neuropathy with liability to pressure palsies (HNPP).

Hereditary neuropathy with liability to pressure palsies (HNPP) is in most cases associated with an interstitial deletion of the same 1.5-Mb region at 17p11.2 that is duplicated in Charcot-Marie-Tooth type 1A (CMT1A) patients. Unequal crossing-over following misalignment at flanking repeat sequences (CMT1A-REP), either leads to tandem duplication in CMT1A patients or deletion in HNPP patients. With the use of polymorphic DNA markers located within the CMT1A/HNPP duplication/deletion region we detected the HNPP deletion in 16 unrelated HNPP patients, 11 of Belgian and 5 of French origin. In all cases, the 1.5-Mb size of the HNPP deletion was confirmed by EcoRI dosage analysis using a CMT1A-REP probe. In the 16 HNPP patients, the same 370/320-kb EagI deletion-junction fragments were detected with pulsed field gel electrophoresis (PFGE), while in CMT1A patients, a 150-kb EagI duplication-junction fragment was seen. Thus, PFGE analysis of EagI-digested DNA with a CMT1A-REP probe allows direct detection of the HNPP deletion or the CMT1A duplication for DNA diagnostic purposes.

Blotting, Southern↗
PubMed1996

A de novo case of hereditary neuropathy with liability to pressure palsies (HNPP) of maternal origin: a new mechanism for deletion in 17p11.2?

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant neuropathy, most often associated with a deletion of the 17p11.2 region, which is duplicated in 70% of patients with Charcot-Marie-Tooth type 1 (CMT1A). Most de novo CMT1A and HNPP cases have been of paternal origin. A rare case of de novo HNPP of maternal origin was analysed to determine the underlying mechanism. Affected individuals in the family carried a deletion corresponding to the CMT1A/HNPP monomer unit associated with a rearrangement of the CMT1A-REP sequences. Segregation analysis of 17p11-p12 markers in the family indicated that the deletion was not generated by unequal crossing over between homologous 17 chromosomes, as in de novo cases from paternal origin, but rather by an intrachromosomal rearrangement. Two distinct mechanisms can therefore lead to the same 17p11.2 deletion. This result suggests that intrachromosomal rearrangement may be specific to maternal transmissions.

Adult↗
PubMed1996

Microsatellite mapping of the deletion in patients with hereditary neuropathy with liability to pressure palsies (HNPP): new molecular tools for the study of the region 17p12 --> p11 and for diagnosis.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant peripheral neuropathy characterized by recurrent episodes of nerve palsies. We have analyzed 11 microsatellite markers from chromosome 17p12 --> p11 in nine French families with HNPP. The three microsatellites D17S839 (afm200yb12), D17S955 (afm317ygl), and D17S921 (afm191xh12) were localized in the deleted region. In allele segregation analyses, the microsatellite D17S793 (afm165zd4) detected two chromosome 17-linked loci, one of which was deleted in HNPP patients. Using these STR markers, we found that the deletion coincided with the CMT1A/HNPP monomer unit in eight of the nine families. In the remaining pedigree, the deletion lay between the centromeric microsatellite D17S805 (afm234tal) and the telomeric marker D17S922 (afm197xh6), which flank the CMT1A monomer unit. Comparison of these data with the available genetic and physical maps of 17p12 --> p11 shows that this region, which is frequently subject to rearrangement-inducing diseases, such as Smith-Magenis syndrome, Charcot-Marie-Tooth type 1A, and HNPP, presents recombination hot spots. Finally, this study demonstrates the usefulness of the D17S122 (RM11GT) and D17S921 (afm191xh12) microsatellites as tools for the molecular diagnosis of HNPP.

Chromosome Aberrations↗
PubMed1996

Recombination hot spot in a 3.2-kb region of the Charcot-Marie-Tooth type 1A repeat sequences: new tools for molecular diagnosis of hereditary neuropathy with liability to pressure palsies and of Charcot-Marie-Tooth type 1A. French CMT Collaborative Research Group.

Charcot-Marie-Tooth type 1A (CMT1A) disease and hereditary neuropathy with liability to pressure palsies (HNPP) are autosomal dominant neuropathies, associated, respectively, with duplications and deletions of the same 1.5-Mb region on 17p11.2-p12. These two rearrangements are the reciprocal products of an unequal meiotic crossover between the two chromosome 17 homologues, caused by the misalignment of the CMT1A repeat sequences (CMT1A-REPs), the homologous sequences flanking the 1.5-Mb CMT1A/HNPP monomer unit. In order to map recombination breakpoints within the CMT1A-REPs, a 12.9-kb restriction map was constructed from cloned EcoRI fragments of the proximal and distal CMT1A-REPs. Only 3 of the 17 tested restriction sites were present in the proximal CMT1A-REP but absent in the distal CMT1A-REP, indicating a high degree of homology between these sequences. The rearrangements were mapped in four regions of the CMT1A-REPs by analysis of 76 CMT1A index cases and 38 HNPP patients, who where unrelated. A hot spot of crossover breakpoints, located in a 3.2-kb region, accounted for three-quarters of the rearrangements, detected after EcoRI/SacI digestion, by the presence of 3.2-kb and 7.8-kb junction fragments in CMT1A and HNPP patients, respectively. These junction fragments, which can be detected on classical Southern blots, permit molecular diagnosis. Other rearrangements can also be detected by gene dosage on the same Southern blots.

Charcot-Marie-Tooth Disease↗
PubMed1995

Clinical, electrophysiologic, and molecular correlations in 13 families with hereditary neuropathy with liability to pressure palsies and a chromosome 17p11.2 deletion.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disease characterized by recurrent episodes of acute nerve palsies. We performed a clinical, electrophysiologic, and molecular study of 13 French families with HNPP associated with a chromosome 17p11.2 deletion in 36 individuals. There were electrophysiologic abnormalities in all symptomatic (n = 28) and asymptomatic (n = 8) deletion carriers, even in childhood. Bilateral delayed distal motor latency of the median nerve at the wrist, reduced sensory velocity in the palm-wrist segment, and delayed distal motor latency or reduced motor velocity in the peroneal nerve was diagnostic in at-risk relatives. This large series confirms the reliability of molecular analysis combined with a simplified electrophysiologic examination for the diagnosis of HNPP associated with 17p11.2 deletion.

Adolescent↗
PubMed1995

[Claude syndrome caused by mesencephalic infarction: 2 cases].

Paramedian midbrain infarcts limited to the oculomotor nerve fibers are uncommon. We studied 2 cases where the clinical syndrome included a third cranial nerve palsy and a contralateral cerebellar ataxia. The CT scan disclosed a paramedian midbrain tegmental infarct, so that it is possible to term our two cases Claude's syndrome. The oculomotor nerve fascicular palsies were complete in one case and limited to the extraocular muscles in the second case. The selective involvement of oculomotor function suggests intraaxial fascicular organisation of the third cranial nerve in the brainstem.

Cerebellar Ataxia↗
PubMed1994

Detection of deletion within 17p11.2 in 7 French families with hereditary neuropathy with liability to pressure palsies (HNPP).

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant peripheral neuropathy which is characterized by recurrent episodes of truncular palsies. We have analyzed the D17S122 locus in 7 French families, including 18 affected members, with microsatellite RM11GT and the RFLP probe VAW409R3a. Only one allele could be detected in all affected individuals with the highly polymorphic RM11GT marker. Allele segregation at D17S122 showed no contribution from the affected parent to the affected child, demonstrating that an interstitial deletion within the 17p11.2 region is associated with HNPP in the 7 families studied. This same region is duplicated, however, in another inherited neuropathy, Charcot-Marie-Tooth 1A disease. This would be the first example of two dominantly inherited diseases caused by a 'in mirror image' deletion/duplication mechanism where a gene dosage effect would be sufficient to produce two different phenotypes characterized by abnormal myelination of the peripheral nerves. The RM11GT microsatellite is an informative tool for the molecular diagnosis of HNPP.

Alleles↗
PubMed1994

Hereditary neuralgic amyotrophy and hereditary neuropathy with liability to pressure palsies: two distinct clinical, electrophysiologic, and genetic entities.

Hereditary neuralgic amyotrophy (HNA) is an autosomal disease characterized by painful episodes of brachial palsy. The presence of tomacula in some patients suggested that HNA might be genetically related to hereditary neuropathy with liability to pressure palsies (HNPP), caused by point mutations in the PMP22 gene or deletion of the region containing this gene. In a clinical, electrophysiologic, and molecular study of two families with HNA, we show that the PMP22 gene is not deleted, duplicated, or mutated in HNA and that the disease is not linked to any other gene in the HNPP deleted region. We conclude that HNA and HNPP are distinct genetic entities.

Adolescent↗
PubMed1994

[Type 1 neurofibromatosis in Tunisia: 66 cases].

A multidisciplinary transversal descriptive study was conducted from June to October 1992 to determine the clinical manifestations and laboratory findings observed in 66 patients with type 1 neurofibromatosis. Diagnostic criteria were those of the National Institute of Health as recommended for subjects over 20 years of age. All patients over the age of 25 had café au lait spots, neurofibromas, lentigines and nodules. Occurrence of lesions of the central nervous system was significantly earlier than peripheral nervous manifestations. The optic glioma was the most frequent lesion of the central nervous system. Complications were observed during the first twenty years of the disease. Based on these findings, we propose a clinical and laboratory work-up designed as a function of age.

Adolescent↗
PubMed1993

[Lipoma of the corpus callosum. 3 case reports and review of the literature].

Lipoma of the corpus callosum is a rare congenital intracranial tumor. Although only 153 cases had been reported as of March 1992, the incidence of this tumor is underestimated (some cases are unpublished and others are asymptomatic). Three cases of lipoma of the corpus callosum diagnosed in children are reported herein. These tumors may be either discovered fortuitously in an asymptomatic patient or responsible for manifestations of which the most common are seizures, headache, and mental disorders. Diagnosis rests on imaging techniques. The main investigation is computed tomography which discloses a mass composed of fat, with or without peripheral calcifications, and also identifies any other malformations such as dysgenesis of the corpus callosum.

Brain Neoplasms↗
PubMed1992

[Neurinomas of the trigeminal nerve in neurofibromatosis. Apropos of two cases and review of the literature].

We report two cases of trigeminal neuroma in patients with Von Recklinghausen neurofibromatosis (NF1). Despite the high frequency of intracranial neuroma in neurofibromatosis, the localization on the fifth cranial nerve is an uncommon findings. In our two cases, neuromas were asymptomatic clinically and electrophysiologically, but computed tomography showed a small nodular lesion in the cerebellopontine cistern, independent of the seventh and eight nerve and which can only correspond to the fifth nerve. MR imaging very clearly demonstrates intracranial neuromas of all cranial nerves.

Adult↗
PubMedDate not supplied

Childhood diabetic neuropathy: a clinical and electrophysiological study.

Clinical diabetic neuropathy in childhood is rare, but electrophysiological involvement of the peripheral nerve is more frequent. We assessed clinically and electrophysiologically the peripheral nervous system of 69 children and adolescents suffering from diabetes mellitus (DM). The mean age of the patients was 12.8 years and the mean age at onset of DM was 6.8 years with a mean disease duration of 6.3 years. Seven patients (10%) had clinical neuropathy of which ankle jerk reflex abolition was the most frequent sign. Twenty patients (29%) had a neurophysiological neuropathy prevalently affecting the lower limbs. Peripheral neuropathy was correlated with patient age, older age at onset, duration of DM, height and poor glycaemic control.

Action Potentials↗