Interferon β-1a in relapsing multiple sclerosis: four-year extension of the European IFNβ-1a Dose-C omparison Study

Background: Multiple sclerosis (MS) is a chronic disease requiring long-term monitoring of treatment. Objective: To assess the four-year clinical efficacy of intramuscular (IM) IFNb-1a in patients with relapsing MS from the European IFNb-1a Dose-C omparison Study. Methods: Patients who completed 36 months of treatment (Part 1) of the European IFNb-1a Dose-C omparison Study were given the option to continue double-blind treatment with IFNb-1a 30 mcg or 60 mcg IM once weekly (Part 2). Analyses of 48-month data were performed on sustained disability progression, relapses, and neutralizing antibody (NA b) formation. Results: O f 608/802 subjects who completed 36 months of treatment, 493 subjects continued treatment and 446 completed 48 months of treatment and follow-up. IFNb-1a 30 mcg and 60 mcg IM once weekly were equally effective for up to 48 months. There were no significant differences between doses over 48 months on any of the clinical endpoints, including rate of disability progression, cumulative percentage of patients who progressed (48 and 43, respectively), and annual relapse rates; relapses tended to decrease over 48 months. The incidence of patients who were positive for NAbs at any time during the study was low in both treatment groups. Conclusion: C ompared with 60-mcg IM IFNb-1a once weekly, a dose of 30 mcg IM IFNb-1a once weekly maintains the same clinical efficacy over four years

Mapping of the familial infantile myasthenia (congenital myasthenic syndrome type Ia) gene to chromosome 17p with evidence of genetic homogeneity

Familial infantile myasthenia is an autosomal recessive disorder, recently classified as congenital myasthenic syndrome type la, Onset of symptoms is at birth to early childhood with significant myasthenic weakness and possible respiratory distress, followed later in life by symptoms of mild to moderate myasthenia, Thirty-six patients of 12 families, seven of them consanguineous, were used to map the familial infantile myasthenia gene. A combination of linkage search through the genome, DNA pooling and homozygosity mapping were employed resulting in the localisation of this disease locus to the telomeric region of chromosome 17p. A maximum led score of 9.28 at theta = 0.034 was obtained between the disease locus and marker locus D17S1537, Haplotype analysis showed all families to be consistent with linkage to this region thus providing evidence for genetic homogeneity of familial infantile myasthenia. Multipoint linkage analysis mapped the disease gene in the similar to 4.0 cM interval between marker loci D17S1537 and D17S1298 with a maximum multipoint lod score of 12.07. Haplotype analysis and homozygosity by descent in affected individuals of the consanguineous families revealed results in agreement with the confinement of the familial infantile myasthenia region within the interval between marker loci D17S1537 and D17S1298

Chromosome 17p-linked myasthenias stem from defects in the acetylcholine receptor epsilon-subunit gene

Objective: To identify and to characterize functionally the mutational basis of congenital myasthenic syndromes (CMS) linked to chromosome 17p. Background: A total of 37 patients belonging to 13 CMS families, 9 of them consanguineous, were investigated. All patients were linked previously to the telomeric region of chromosome 17p. Two candidate genes in this region encode synaptobrevin 2, a presynaptic protein, and the epsilon-subunit of the acetylcholine receptor (AChR). Direct sequencing of the synaptobrevin 2 gene revealed no mutations. The authors thus searched for mutations in the epsilon-subunit gene of AChR. Methods: Direct sequencing of the AChR epsilon-subunit, restriction analysis, allele-specific PCR, and expression studies in human embryonic kidney cells were performed. Results: The authors identified two previously characterized and five novel epsilon-subunit gene mutations, all homozygous, in the 13 kinships. Two of the novel mutations are truncating (epsilon 723delC and epsilon 760ins8), one is a missense mutation in the signal peptide region (epsilon V-13D), one is a missense mutation in the N-terminal extracellular domain (epsilon T51P), and one is a splice donor site mutation in intron 10 (epsilon IVS10+2T-->G). Unaffected family members have no mutations or are heterozygous. Expression studies indicate that the four novel mutations in the coding region of the gene and the most likely transcript of the splice-site mutation, which skips exon 10, are low-expressor or null mutations. Conclusions: Chromosome 17p-linked congenital myasthenic syndromes are caused by low-expressor/null mutations in the AChR epsilon-subunit gene. Mutations in this gene are a common cause of CMS in eastern Mediterranean countries

Double-blind randomized multicenter dose-comparison study of interferon-beta-1a (AVONEX):rationale, design and baseline data

We describe the rationale and design of a double-blind, randomized multicenter, dose-comparison study of interferon-beta-Ia (IFN-beta -Ia: AVONEX(R) in the treatment of relapsing multiple sclerosis (MS). The study is expected to provide quantitative insights on the dose range for optimal clinical benefits in MS. The study involves 802 patients in 10 European countries who have EDSS scores 2.0-5.5, and who have experienced at least two relapses within the 3 years prior to enrolment Patients ore randomized to receive once-weekly intramuscular injections of IFN-beta -Ia 30 or 60 mcg for at least 3 years. The primary endpoint of the study is the effect of IFN-beta -Ia therapy on the time to sustained progression of disability. For patients with a baseline EDSS less than or equal to 4.5, sustained progression of disability is defined as a I point increase in EDSS from baseline, maintained for 6 months. For patients with baseline EDSS less than or equal to 5, sustained progression of disability is defined as reaching on EDSS greater than or equal to 6.0 maintained for 6 months. EDSS scores will be determined every 3 months. A series of prospectively defined secondary and tertiary efficacy endpoints will be examined Safety will be monitored throughout the study. Magnetic resonance imaging (MRI) with and without gadolinium-enhancement has been Performed in at least 358 patients at baseline and repeated annually after enrolment In a subset of these patients, a frequent MRI study is also being performed