Allelic association of sequence variants in the herpes virus entry mediator-B gene (PVRL2) with the severity of multiple sclerosis.

Discrepant findings have been reported regarding an association of the apolipoprotein E (APOE) gene with the clinical course of multiple sclerosis (MS). To resolve these discrepancies, we examined common sequence variation in six candidate genes residing in a 380-kb genomic region surrounding and including the APOE locus for an association with MS severity. We genotyped at least three polymorphisms in each of six candidate genes in 1,540 Caucasian MS families (729 single-case and multiple-case families from the United States, 811 single-case families from the UK). By applying the quantitative transmission/disequilibrium test to a recently proposed MS severity score, the only statistically significant (P=0.003) association with MS severity was found for an intronic variant in the Herpes Virus Entry Mediator-B Gene PVRL2. Additional genotyping extended the association to a 16.6 kb block spanning intron 1 to intron 2 of the gene. Sequencing of PVRL2 failed to identify variants with an obvious functional role. In conclusion, the analysis of a very large data set suggests that genetic polymorphisms in PVRL2 may influence MS severity and supports the possibility that viral factors may contribute to the clinical course of MS, consistent with previous reports.

Clinical characteristics of African Americans vs Caucasian Americans with multiple sclerosis.

BACKGROUND: African American (AA) individuals are thought to develop multiple sclerosis (MS) less frequently than Caucasian American (CA) individuals. OBJECTIVE: To compare the clinical characteristics of AA and CA patients with MS. METHODS: The clinical features of MS were compared in a large retrospective cohort of AA (n = 375) and CA (n = 427) subjects. RESULTS: The proportion of women to men was similar in AA and CA subjects (81% [AA] vs 77% [CA]; p = 0.122). There were no differences in the proportions of subjects with relapsing-remitting, secondary progressive, primary progressive, and progressive relapsing MS. The median time to diagnosis was 1 year after symptom onset in AA subjects and 2 years after symptom onset in CA subjects (p = 0.0013). The age at onset was approximately 2.5 years later in AA than CA subjects (33.7 vs 31.1 years; p = 0.0001). AA subjects presented with multisite signs and symptoms at disease onset more often than CA subjects (p = 0.018). Clinical involvement restricted to the optic nerves and spinal cord (opticospinal MS) occurred in 16.8% of AA patients compared with 7.9% of CA patients (p < 0.001). Transverse myelitis also occurred more frequently in AA subjects (28 vs 18%; p = 0.001). Survival analysis revealed that AA subjects were at higher risk for development of ambulatory disability than CA subjects. After adjusting for baseline variations and differences in therapeutic interventions, AAs were at 1.67-fold greater risk for requiring a cane to ambulate than CA patients (p < 0.001). There was a trend suggesting that AAs were also at greater risk for development of wheelchair dependency (p = 0.099). Adjusted Cox proportional hazard models showed that this effect was in part attributable to the older age at onset in AAs (p < 0.001). CONCLUSIONS: Compared with multiple sclerosis (MS) in Caucasian Americans, African American patients with MS have a greater likelihood of developing opticospinal MS and transverse myelitis and have a more aggressive disease course.