[Andermann syndrome in an Algerian family: suggestion of phenotype and genetic homogeneity]

Andermann syndrome or Agenesis of the Corpus Callosum with Polyneuropathy (MIM 218000) is an autosomal recessive disease almost exclusively found in Québec. Only few cases have been reported in other populations. The locus for Andermann syndrome was assigned to chromosome 15q13-q15 in French Canadian families. We performed a haplotype analysis with two markers of this chromosomal region in an Algerian consanguineous family with two affected sibs. The children were homozygous for both markers, suggesting genetic homogeneity in Andermann syndrome.

[The role of MRI in the diagnosis and the natural course of multiple sclerosis]

Magnetic resonance imaging (MRI) is very sensitive in depicting multiple sclerosis (MS) lesions, but its specificity is poor. New sequences such as fast spin echo and FLAIR (fluid attenuated inversion recovery) improve the detection of lesions. The exploration of the whole central nervous system, brain, optic nerves and spinal cord improves sensitivity and specificity. The existence of lesions at different ages responds to temporal dissemination. MRI has also allowed to better understand the natural history of MS, showing 5 to 10 times more radiological than clinical activity. In case of isolated demyelinating syndrome, MRI is the best predictor of the occurrence of definite MS and of the severity of disability in the subsequent 10 years. However, the diagnosis of MS remains clinical, and systematic control MRI are not useful in clinical practice.

Correlating multiple MRI parameters with clinical features: an attempt to define a new strategy in multiple sclerosis

MRI is the most powerful imaging technique in managing patients with suspected or confirmed multiple sclerosis (MS). However, conventional MRI variables show nonspecific abnormalities weakly correlated with clinical progression of the disease. New techniques, now routinely available, offer better characterisation of the pathophysiology. We combined conventional MRI, including lesion load, contrast enhancement and "black holes" with magnetisation transfer and diffusion-weighted imaging and localised proton MR spectroscopy (MRS) to study their relationship with disability, course and duration of MS. The variables that were the most significantly linked to the course of the disease (relapsing remitting versus secondary progressive) were lesion load, mean overall magnetisation transfer ratio and apparent diffusion coefficient (MGADC), the percentage of ADC in (PADCIMD), and out of (PAD-COMD) modal distribution, and the ratio N-acetylaspartate and creatine-containing compounds on MRS of the centrum semiovale. MGADC and PADCIMD were the independent factors most related to disability and duration of disease. Combining MRI techniques is clinically relevant and feasible for studies of MS and may be applied to other diseases of the central nervous system.

[A case of mitochondrial cytopathy (MERFF) without ragged red fibers at the onset]

We report a case of a mitochondrial cytopathy (MERRF) with a late diagnosis because of the absence of Ragged-Red Fibers (RRF) in the first muscular biopsy performed in childhood. Eight years after the onset of the disease the familial history and the clinical manifestations were very suggestive of a mitochondrial cytopathy and a second biopsy was performed confirming the diagnosis of MERRF. The authors discuss several hypotheses to explain the negativity of the first muscular biopsy. The absence of ragged-red fibers does not exclude the diagnosis of a mitochondrial cytopathy and other investigations are justified such as the biochemical study of the respiratory chain and the molecular analysis of mitochondrial DNA.

[Study with localized proton magnetic resonance spectroscopy of 31 multiple sclerosis lesions: correlations with clinical and MRI features]

We have analyzed with localized proton magnetic resonance spectroscopy (MRS) 31 lesions in 28 patients with multiple sclerosis (MS). The course of the disease was either relapsing remitting, secondary progressive, or primary progressive. Four patients had an isolated neurological syndrome suggestive of MS. The decrease in the NAA/Cre ratio and the raise of the Cho/Cre ratio were more pronounced in patients with an acute isolated neurological syndrome, suggesting the predominance of an inflammatory process, and the presence of an axonal dysfunction in the initial course of the lesion. The NAA/Cre ratio was negatively correlated with clinical disability and thus could be used as an index of disease activity. Patients with a secondary progressive course exhibited a significant increase in the Myo/Cre ratio compared to those with a relapsing remitting course. Thus, there may be an association between the evolution towards a progressive disease and axonal loss or the development of gliosis. The isointense lesions to the cerebrospinal fluid on MRI T1 weighted sequences were characterized by a sharp raise in the Cho/Cre ratio suggesting demyelination and/or intense inflammation. Gadolinium enhanced lesions were not characterized by a specific neurochemical profile.

A longitudinal study of callosal atrophy and interhemispheric dysfunction in relapsing-remitting multiple sclerosis

OBJECTIVES

To determine if callosal atrophy and interhemispheric dysfunction can be detected in the early stages of relapsing-remitting multiple sclerosis (MS) and to evaluate their progression in relation to the disability and evolution of lesions seen on magnetic resonance imaging during a 5-year period.

METHODS

We compared 30 patients who had clinically definite early-onset replasing-remitting MS and mild disability with control subjects. Regional and segmental callosal size and extent of white matter abnormalities on magnetic resonance imaging, as well as performance on tasks exploring interhemispheric transfer of motor, auditory, and sensory information were assessed. Patients with MS were evaluated at baseline and after 5 years. Physical disability was determined at both times using the Expanded Disability Status Scale score.

RESULTS

Patients with MS were seen with significant callosal atrophy and functional impairment of interhemispheric transfer at baseline that worsened during the 5-year study. A significant correlation was found between the magnitude of disability and the severity of morphological and functional callosal involvement at baseline. This association persisted at year 5. Baseline clinical characteristics such as age and prestudy relapse rate were unrelated to callosal size or interhemispheric performance. However, the number of baseline T2-weighted lesions was correlated with callosal involvement and this relation persisted at year 5.

CONCLUSION

Patients who had relapsing-remitting MS in the early stages of the disease and mild disability had significant callosal involvement that progressed over time. The relationship between disability, T2-weighted lesions load, and degree of morphological and functional callosal impairment confirm the potential value of using callosal dysfunction as a surrogate marker of disease progression in MS.

[Magnetic resonance spectroscopy in multiple sclerosis]

Magnetic resonance spectroscopy allows in vivo neurochemical exploration of multiple sclerosis (MS) lesions and normal appearing white matter on MRI. It gives insights into pathophysiology: inflammation (increase of choline), recent demyelination (increase in lipids and choline), axonal dysfunction (decrease of NAA), gliosis (increase of myoinositol). The spectroscopic profile of lesions is not specific to MS. Therefore MRI remains the first investigation to perform when MS is suspected. However, spectroscopy is a sensitive, reproducible, non invasive tool which may provide an index of activity. In the future, spectroscopy may contribute in homogenizing patient selection for clinical trials and might be used, in association with MRI, to evaluate therapeutic efficiency. Spectroscopy might also influence therapeutic choices by identifying the prevailing lesional mechanism: inflammation, demyelination, axonal destruction, or gliosis.

[The first episode of central nervous system demyelinization and hepatitis B virus vaccination]

BACKGROUND

Central nervous system (CNS) demyelinating episodes have been described following numerous vaccines but there is no definite conclusion about a causal relationship. Recently, in France, in the context of an Expanded Program on Immunization, several cases of CNS demyelination have been observed following injection of recombinant hepatitis B (HB) vaccine, leading to great concern.

METHODS

We performed a hospital-based case-control study of 121 patients with a first episode of CNS demyelination occuring between July 1993 and December 1995 and 121 age and sex matched controls seen in the same period. Data on vaccinations history of cases and controls were collected by a postal questionnaire and confirmed by a phone interview.

RESULTS

Adjusted odds ratio (OR) obtained from conditional logistic regression between a first episode of CNS demyelination and any vaccination were equal to 1.4 (95 p. 100 CI 0. 5-4.3) for an exposure within the 60 previous days and 2.1 (95 p. 100 CI 0.7-6.0) for an exposure within the 61-180 previous days. Similar results were found for HB vaccine exposure within the 60 previous days (adjusted OR=1.7, 95 p. 100 CI 0.5-6.3) or within the 61 to 180 previous days (adjusted OR= 1.5, 95 p. 100 CI 0.5-5.3).

CONCLUSION

These findings did not permit to exclude confidently an association between HB vaccine and the occurrence of a first CNS demyelinating episode.

Cytokines in genetic susceptibility to multiple sclerosis: a candidate gene approach. French Multiple Sclerosis Genetics Group

The immune system is involved in the pathophysiology of multiple sclerosis (MS) but the initiating antigen(s) is not yet identified. Since cytokines control both the intensity and the quality of the immune response they may be relevant candidates for the genetic susceptibility to MS. To analyze the contribution of type 1 and type 2 cytokine and cytokine receptor genes in the genetic susceptibility to MS, we have examined, in 116 French MS sibpairs, whether there is significant linkage between MS and 15 cytokine or cytokine receptor genes using 31 highly polymorphic genetic markers. The data were analyzed using the maximum likelihood score and the transmission disequilibrium approaches. None of the candidate genes tested was significantly linked to MS on the whole population. However, after stratification of the analysis on the basis of sharing (or not) of the HLA-DRB1*1501 allele, indication of linkage was found for the IL2-RB gene. These findings suggest that the IL2-RB locus contributes to the genetic susceptibility in a subgroup of MS patients.

Chromosome 17q22-q24 and multiple sclerosis genetic susceptibility. American-French Multiple Sclerosis Genetic Group

Recently, genome-wide searches for multiple sclerosis (MS) susceptibility genes have suggested that the chromosome 17q22-q24 region might contain susceptibility genes in two sets of families of different ethnic backgrounds (Finnish and British). Therefore, we decided to test this region in two sets of families of different ethnic backgrounds (American and French), but collected according to the same diagnostic criteria. All lod-score values were non-significant. Moreover, we could exclude that the 17q22-24 region might contain a gene increasing the sibling recurrence risk of MS over 1.4, rendering the existence of such a gene very unlikely, at least in the group of tested families.

Normal-appearing white matter in optic neuritis and multiple sclerosis: a comparative proton spectroscopy study

We investigated neurochemical abnormalities in the normal-appearing white matter (NAWM) on MRI of patients with optic neuritis (ON) and compared them to those of patients with multiple sclerosis (MS). Patients with ON (42) were classified into three groups according to abnormalities on brain MRI. Patients with MS (55) were divided in two groups: relapsing remitting MS (RRMS) and secondary progressive MS (SPMS). All patients underwent MRI of the brain and localised proton magnetic resonance spectroscopy (MRS) of NAWM. The results were compared to those of 15 controls. Patients with MS had significant abnormalities compared with controls and with patients with ON. Patients with RRMS and those with ON had comparable MRS parameters, while patients with SPMS had significant spectroscopic abnormalities in comparison with controls, but also with patients with RRMS. These changes consisted of a decrease in N -acetylaspartate, a neuronal marker, which may reflect axonal dysfunction and/or loss. MRS abnormalities were detected in 14 patients with ON (27 %). The main abnormalities consisted of a decrease in N -acetylaspartate, an increase in choline-containing compounds at long echo times, and the presence of free lipid peaks at short echo times. MRS of the NAWM on MRI may prove useful for detecting neurochemical brain abnormalities in ON not visible on MRI.

Localized proton magnetic resonance spectroscopy in relapsing remitting versus secondary progressive multiple sclerosis

OBJECTIVE

To determine the efficacy of MRS in discriminating between relapsing remitting (RR) and secondary progressive (SP) MS.

METHODS

MRS at long and short echo times was carried out in 104 patients with MS stratified for clinical course (RR or SP), and the results were compared with those of 15 control subjects. Normal-appearing white matter (NAWM) was studied in 55 patients, and a high-T2-signal area on MRI in 49 others.

RESULTS

At long echo times, there was a highly significant decrease in the ratios N-acetyl-aspartate/creatine (NAA/Cr) and NAA/ choline (Cho) in high-T2-signal areas and in the NAWM in patients with an SP course compared with control subjects and patients with an RR course. There was a significant negative correlation between these ratios and clinical disability measured by Expanded Disability Status Scale score, which was independent of disease duration. Discriminant values between patients with RR and SP courses were found in the NAWM (NAA/Cr = 1.75 and NAA/Cho = 1.5), but not in high-T2-signal areas. At short echo times, there was a significant increase in the ratio myoinositol/Cr in high-signal areas of patients with an SP course compared with control subjects, and the presence of abnormal resonances in the lesions and NAWM for free amino acids and lipids (in 30% and 8%, respectively) and GLX complex (glutamine, glutamate, gamma-aminobutyric acid; 16% and 20%, respectively).

CONCLUSIONS

Studying normal-appearing white matter on MRI with MRS allows discrimination between relapsing remitting and secondary progressive patients. In the NAWM of patients with MS and an SP course, severe axonal loss/dysfunction is negatively correlated to clinical disability and independent of the duration of the disease.

Encephalitis after hepatitis B vaccination: recurrent disseminated encephalitis or MS?

OBJECTIVE

To describe clinical and MRI features of patients with a disease suggestive of CNS inflammation after hepatitis B vaccination.

METHODS

Eight patients with confirmed CNS inflammation occurring less than 10 weeks after hepatitis B vaccination are described. They received follow-up clinically and on MRI for a mean period of 18 months.

RESULTS

Clinical and MRI findings were compatible with acute disseminated encephalomyelitis. However, clinical follow-up, repeated MRI, or both showed the persistence of inflammatory activity, which makes this encephalitis more suggestive of MS than of acute disseminated encephalomyelitis.

CONCLUSION

The persistent inflammatory activity observed clinically and on MRI in these patients is comparable with that usually observed in MS. Epidemiologic studies are currently testing the hypothesis of a triggering role of hepatitis B vaccination in CNS demyelination.

Familial factors influence disability in MS multiplex families. French Multiple Sclerosis Genetics Group

BACKGROUND

Both genetic and environmental factors play a role in the pathophysiology of MS and may influence the clinical expression of the disease.

OBJECTIVE

To determine the contribution of familial factors to the clinical expression of MS.

METHODS

The French Multiple Sclerosis Genetics Group identified 87 sibling pairs. For each patient, sex, age at onset, duration of the disease, and disease course from onset were recorded. Disability was determined by the progression index (PI), defined as the ratio of the Expanded Disability Status Scale (EDSS) score disease duration when the latter exceeded 5 years. Statistical analyses were performed either with a group of patients (clinical features, relation between human leukocyte antigen and clinical features) or with a group of sibpairs (concordance for clinical features).

RESULTS

The mean age at onset was 29.6 years, the ratio of women to men was 59:28, and the mean PI was 0.27. There was no correlation for disease course and age at onset between sibs with MS. In contrast, we observed a weak but significant correlation of the PI in MS sibpairs (r = 0.234, p = 0.03).

CONCLUSION

This study revealed a concordance in MS sibling pairs for the disease severity, supporting the hypothesis that the degree of disability might be partly influenced by familial factors (environmental or genetic).

A systematic study of oligodendrocyte growth factors as candidates for genetic susceptibility to MS. French Multiple Sclerosis Genetics Group

OBJECTIVE

To test 23 genes coding for growth factors and their receptors as candidates for MS genetic susceptibility in 84 multiplex families of French origin by linkage analysis.

BACKGROUND

Epidemiologic studies have indicated that genetic susceptibility in MS exists. To identify MS susceptibility genes, association and linkage studies were performed with candidate genes suggested by the pathology of MS. The most consistent result was genetic association and linkage of MS to human leukocyte antigen (HLA) DR15. Recent advances in the knowledge of MS pathology have suggested that the oligodendrocyte, the myelin-forming cell in the CNS, and its growth factors might play a crucial role in MS.

METHODS

Fifty-two polymorphic markers within or flanking 23 candidate genes were used. Data were analyzed with the maximum likelihood score (MLS) approach. We also searched for a genetic interaction with HLA.

RESULTS

Negative results were obtained for all candidate genes. The lower limits of the relative risk (Xs) possibly excluded for any candidate gene ranged from 1.3 to 2.8. Positive MLS values (up to 0.93) were observed for transforming growth factor beta 3 (TGFbeta3) in HLA DR15-associated families, suggesting a possible role for this growth factor in interaction with HLA.

CONCLUSIONS

Oligodendrocyte growth factors do not play a significant role in MS genetic susceptibility, at least in the tested sample. TGFbeta3, the only gene highlighted by this study, deserves further analysis.

Apolipoprotein E and multiple sclerosis: a biochemical and genetic investigation

Apolipoprotein E (apo E) is postulated to be a major lipid carrier protein in the brain involved in brain development and repair. Multiple sclerosis (MS) is a major demyelinating disease characterized by destruction of myelin and marked alteration of myelin cholesterol and lipid metabolism. We have determined serum and cerebrospinal fluid (CSF) apo E concentrations using an original time-resolved immunofluorometric assay and calculated intrathecal apo E concentration. Apo E concentrations were determined in 13 control subjects and 129 neurological patients: 34 definite MS patients, 25 with Guillain-Barré syndrome (GBS), 32 with amyotrophic lateral sclerosis (ALS) and 38 with other neurological diseases. Seven clinical parameters (sex, age, age at MS onset, duration of the disease, course, clinical status and disability score) were considered in MS patients. Significant (P < 0.01) decrease in CSF apo E was observed in MS, linked to a decrease in intrathecal apo E. The decreased CSF apo E concentration in MS patients occur independent of the apo E genotype. Apo E is considered as a neurotrophic factor in the brain. Any decrease in intrathecal apo E synthesis would thus contribute to progression of neurological diseases, such as MS.

T cell receptor V beta 5 and V beta 17 clonal diversity in cerebrospinal fluid and peripheral blood lymphocytes of multiple sclerosis patients

To better characterize the cellular immune response taking place in the MS central nervous system, we investigated the blood and CSF T cell receptor (TCR) V beta 5 and V beta 17 repertoire in HLA-typed patients with recently diagnosed MS or other neurological diseases (OND). Using a RT-PCR based technique, we analysed directly ex vivo the CDR3 size of TCR beta chains utilizing V beta 5 (eight patients with MS and one with OND) or V beta 17 (eight patients with MS and six with OND) gene segments on paired blood-CSF samples. Globally, the analysis of V beta 5-J beta and V beta 17-J beta repertoire showed a less diverse pattern in the CSF samples than in the corresponding peripheral blood lymphocytes both in MS and in OND patients. However, we did not detect any recurrent clonal expansion within the V beta 5+ T cells in MS patients, underlining the potential limits of V beta 5-based immunotherapy in MS. We found an expanded T cell population using the same V beta 17-J beta 1.6 combination with identical CDR3 length in the CSF of three MS patients and none of the control patients. These results suggest selective expansion of T cells expressing this segment gene in the MS central nervous system.