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Biomedical subjects

J P Bouchard

Publications and source records attributed to J P Bouchard.

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

Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion.

We studied genotype-phenotype correlations in a group of 100 patients with typical Friedreich ataxia (FRDA), and in three groups of patients with atypical clinical presentations, including 44 Acadian FRDA, 8 late-onset FRDA (LOFA), and 6 FRDA with retained reflexes (FARR). All patients, except 3 with typical FRDA, carried two copies of the FRDA-associated GAA triplet repeat expansion. Overall, the phenotypic spectrum of FRDA appeared to be wider than defined by the currently used diagnostic criteria. Our study indicated the existence of several sources of variability in FRDA. Patients with larger GAA expansions tended to have earlier onset and were more likely to show additional manifestations of the disease. Mitotic instability of the expanded GAA repeats may partially account for the limited degree of correlation between expansion sizes as determined in lymphocytes and clinical parameters. Some clinical variants associated with specific FRDA haplotypes, such as Acadian FRDA and FARR, turned out to be unrelated to expansion sizes. No polymorphism in the frataxin coding sequence could be associated with these clinical variants.

Adolescent↗
PubMed1997

Role of the striatum, cerebellum, and frontal lobes in the learning of a visuomotor sequence.

This study was designed to examine the role of the striatum, cerebellum, and frontal lobes in the implicit learning of a visuomotor sequence. The performance of patients with idiopathic Parkinson's disease (PD), with damage to the cerebellum, or with a circumscribed lesion to the frontal lobes was thus compared to that of separate groups of matched normal control subjects on an adapted version of the Repeated Sequence Test. This paradigm consists of a visual reaction-time task with a fixed embedded sequence of finger movements to be performed based on presentation of visual stimuli. Subjects received four blocks of trials (i.e., 40 presentations of a 10-item sequence) per day over 6 training days. Following the last experimental session, subjects were also given two tests measuring their declarative knowledge of the sequence. Only PD patients with a bilateral striatal-dysfunction or patients with lesions to the cerebellum failed to improve their performance in the last three training sessions, hence suggesting an impairment late in the acquisition process. Further analyses revealed that such impairment was mainly implicit in nature, and that it could not be ascribed to a general decline in cognitive functioning, to mood disturbances, or to the severity of the motor symptoms. By contrast, the level of declarative knowledge of the sequence did not differ between the three clinical groups and their respective groups of normal subjects. These findings suggest that, unlike declarative memory, the incremental acquisition of a new visuomotor skill depends upon the integrity of both the striatum and the cerebellum, but not of the frontal lobes.

Adult↗
PubMed1997

André Barbeau and the oculopharyngeal muscular dystrophy in French Canada and North America.

André Barbeau (1931-1986) is best known world-wide in the neurologic community for his contributions to the study of Parkinson's disease, Huntington's chorea and Friedreich's ataxia. But in Québec, Canada, his name is associated with oculopharyngeal muscular dystrophy (OPMD), often called here 'maladie de Barbeau', on which he conducted a series of genealogic, genetic and clinical studies early in his career, most intensively from 1964 to 1966. He then demonstrated that most of the reported cases in North America could be traced back to French-Canadian ancestors. Furthermore, he identified this ancestor couple and linked them with a probable case in Niort, in France. Because he was the first to see over a hundred patients, his clinical studies were definitive. He did little work on OPMD after 1967 when he rushed back to the study of L-DOPA in the treatment of Parkinson's disease, a work that he had previously so brilliantly pioneered.

Family Health↗
PubMed1997

Recent studies on oculopharyngeal muscular dystrophy in Québec.

In 1990, we launched a major study to ascertain the clinical picture of OPMD in Québec and to identify large families for linkage analysis. In 14 patients, the chromosomes were karyotyped to eliminate any deletion or translocation. Relevant family information and clinical data were computerized and correlations were sought for the age of onset, the identification of the first symptom and the distribution of weakness. A simple test to detect dysphagia was validated. Twenty-one families have taken part in the study, which led to our localization of the gene in 1995 [Brais B, Xie Y-G, Sanson M, et al. Hum Mol Genet 1995; 4:429-434]. At least one case in each family underwent muscle biopsy to confirm the presence of the typical nuclear filaments found in OPMD. Electrodiagnostic and pathologic studies were also conducted to better understand the disease process. An illustrative case is presented.

Adult↗
PubMed1997

Oculopharyngeal muscular dystrophy in Italy.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant myopathy particularly frequent in Québec. The few Italian cases thus far described with bilateral ptosis, dysphagia and variable muscle weakness, show non-specific dystrophic findings on muscle biopsies by light microscopy. We describe a 70-year-old Italian woman with an adult-onset ptosis, mild dysphagia and proximal muscle weakness belonging to a family segregating OPMD according to an autosomal dominant mode of inheritance. Clinical features of four of her relatives are reviewed. Muscle biopsy studied by electron microscopy showed the typical 8.5 nm in diameter intranuclear filamentous inclusions (INI). To our knowledge, this is the first Italian report of OPMD with INI. The identification of nuclear inclusions is mandatory in order to confirm the diagnosis prior to linkage analysis.

Aged↗
PubMed1997

Using the full power of linkage analysis in 11 French Canadian families to fine map the oculopharyngeal muscular dystrophy gene.

Oculopharyngeal muscular dystrophy (OPMD) is a late onset autosomal dominant muscular dystrophy with a high prevalence in the French Canadian population. We report linkage analysis with 7 chromosome 14q polymorphic markers in 11 large French Canadian families. An observed recombination in one family establishes D14S283 as the new centromeric flanking marker, therefore reducing the previously reported candidate interval from 5cM to 2cM. The highest two-point LOD score was 26.05 at theta = 0.01 for MYH7.1. Multipoint analysis suggested that the OPMD genes lies within a 1.5cM region around D14S990. This study of large French Canadian families underlines the great power of this population to fine map disease genes.

Adult↗
PubMed1997

Upper esophageal sphincter myotomy in oculopharyngeal muscular dystrophy: long-term clinical results.

From 1980 to 1995, 53 patients with oculopharyngeal muscular dystrophy (OPMD) underwent an upper esophageal sphincter (UES) myotomy for the control of marked dysphagia. From this number, a group of 21 patients had been evaluated for preoperative and postoperative symptoms in 1987. The same clinical assessment was performed in 1995 by an independent evaluator for a total of 37 patients including 12 patients from the first group. As a whole, after a mean follow-up of 6.2 years, surgery succeeded in 18 patients (49%), gave a partial improvement in 12 (32%) and failed in seven (19%). The 12 patients evaluated twice (in 1987 and 1995) have had very good early results, 8-69 months after UES myotomy: dysphagia was totally relieved in eight patients, occurred rarely in three and was moderate in one. Nevertheless, the very long-term follow-up (8 years later) has shown a recurrence of the swallowing and tracheobronchial symptoms in many cases.

Adult↗
PubMed1997

A pilot study on upper esophageal sphincter dilatation for the treatment of dysphagia in patients with oculopharyngeal muscular dystrophy.

Upper esophageal sphincter (UES) dilatation was done for the treatment of moderate to severe dysphagia with a Maloney bougie in 14 patients with oculopharyngeal muscular dystrophy (OPMD) or with an achalasia dilator in three patients. The severity of dysphagia prior to UES dilatation was evaluated by a 15-point dysphagia score, a pharyngeal and esophageal manometry and a radionuclide pharyngoesophageal transit study. Using actuarial life table, the improvement rate after dilatation with Maloney bougie was 64.3% (95% CI 39.2-89.4) at 3- and 6-month follow-ups, and was 55.7% (95% CI 28.9-82.5) at 12- and 18-month follow-ups. At 3-month post-dilatation, we observed a significant reduction of the mean dysphagia score from 9.6 to 7.2 (P = 0.05). No significant manometric or radionuclide factors were found to predict effective dilatation. The results of this pilot study showed that UES dilatation with Maloney bougie or achalasia dilator may be an effective treatment of moderate dysphagia in patients with OPMD. However, further studies with larger sample sizes are needed to corroborate these results and to assess long-term outcome.

Adult↗
PubMed1996

Friedreich ataxia in Acadian families from eastern Canada: clinical diversity with conserved haplotypes.

The gene for Friedreich ataxia (FRDA), an autosomal-recessive neurodegenerative disease, remains elusive. The current candidate region of about 150 kb lies between loci FR2 and F8101 near the D9S15/D9S5 linkage group at 9q13-21.1. Linkage homogeneity between classical FRDA and a milder, slowly progressive Acadian variant (FRDA-Acad) has been demonstrated. An extended D9S15-D9S5 haplotype (C6) predominates in FRDA-Acad chromosomes from Louisiana. We studied 10 Acadian families from New Brunswick, Canada. In eight families, affected individuals conformed to the clinical description of FRDA-Acad; in one, 2 sibs presented with spastic ataxia (SPA-Acad). In the last family, 2 sibs had FRDA-Acad, and one had SPA-Acad. We found that SPA-Acad is linked to the FRDA gene region. The C6 haplotype and a second major haplotype (B7) were identified. The same ataxia-linked haplotypes segregated with both FRDA-Acad and SPA-Acad in two unrelated families. The parental origins of these haplotypes were different. Our observation of different phenotypes associated with the same combination of haplotypes may point to the influence of the parent of origin on gene expression, indicate the effect of modifier genes, or reflect the presence of different mutations on the same haplotypes. Our findings underline the need to investigate families with autosomal-recessive ataxias for linkage to the FRDA region, despite lack of key diagnostic manifestations such as cardiomyopathy or absent deep-tendon reflexes.

Canada↗
PubMed1996

A full genome search in multiple sclerosis.

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

Chromosome Mapping↗
PubMed1996

Clinical trials of riluzole in patients with ALS. ALS/Riluzole Study Group-II.

Two double-blinded, placebo-controlled clinical trials of riluzole have now been carried out in more than 1,100 patients with ALS. The results of both studies show a modest benefit in prolonging survival that is statistically significant. These results led to the availability of this drug by the Food and Drug Administration for use in the United States beginning in early 1996. This is the first drug that has been available for ALS. It begins a new era in both basic and clinical research in an attempt to find a cure for this disease.

Adult↗
PubMed1996

The gene responsible for a severe form of peripheral neuropathy and agenesis of the corpus callosum maps to chromosome 15q.

Peripheral neuropathy with or without agenesis of the corpus callosum (ACCPN) is a devastating neurodegenerative disorder that is transmitted as an autosomal recessive trait. Genealogical studies in a large number of affected French Canadian individuals suggest that ACCPN results from a single founder mutation. A genomewide search using 120 microsatellite DNA markers in 14 French Canadian families allowed the mapping of the ACCPN gene to a 5-cM region on chromosome 15q13-q15 that is flanked by markers D15S1040 and D15S118. A maximum two-point LOD score of 11.1 was obtained with the marker D15S971 at a recombination fraction of 0. Haplotype analysis and linkage disequilibrium support a founder effect. These findings are the first step in the identification of the gene responsible for ACCPN, which may shed some light on the numerous conditions associated with the progressive peripheral neuropathy or agenesis of the corpus callosum.

Agenesis of Corpus Callosum↗
PubMed1995

The oculopharyngeal muscular dystrophy locus maps to the region of the cardiac alpha and beta myosin heavy chain genes on chromosome 14q11.2-q13.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset autosomal dominant muscular dystrophy which presents typically after the age of 50 with progressive eyelid drooping and an increasing difficulty in swallowing. Though OPMD has a world-wide incidence, it is more common in the French Canadian population. We have identified a homogeneous group of families and studied 166 polymorphic markers as part of a genome search before establishing linkage to chromosome 14. We determined that the OPMD locus maps to a less than 5 cM region of chromosome 14q11.2-q13. The maximum two-point lod score in three French Canadian families of 14.73 (theta = 0.03) was obtained for an intronic cardiac beta myosin heavy chain gene (MYH7) marker. The regional localization for the OPMD locus raises the intriguing possibility that either the cardiac alpha or beta myosin heavy chain genes may play a role in this disease.

Base Sequence↗
PubMed1994

Red blood cell Cu/Zn superoxide dismutase activity in sporadic amyotrophic lateral sclerosis.

To determine the possible role of Cu/Zn superoxide dismutase (SOD1) in the pathophysiology of sporadic amyotrophic lateral sclerosis (SALS), we measured SOD1 activity in red blood cell lysates in patients with SALS. SOD1 activity in red blood cell lysates was independent of age and sex in control patients, and no significant difference was found between the levels of SOD1 activity in controls (1174.8 +/- 213, n = 29) and SALS patients (1203.4 +/- 214, n = 27). These results suggest that point mutations in the SOD1 gene are apparently unrelated to SALS.

Adult↗