164-P: HLA DQB1 06:09 SIGNIFICANTLY INCREASES THE RISK OF MULTIPLE SCLEROSIS AMONGST PARSIS (ZOROASTRIANS) OF INDIA

Abstract

The frequency of Multiple Sclerosis (MS) varies worldwide. Zoroastrians (Parsis) of Mumbai, India comprise a tiny inbred group who have shown a significantly higher prevalence of MS. DNA typing of HLA Class II DRB1 and DQB1 alleles was performed on 13 Parsi patients. DNA was extracted from blood samples of 13 MS Parsi patients (remitting relapsing) and 50 healthy Parsi controls. Low and high resolution HLA-DRB1 and DQB1 molecular typing was performed by polymerase chain reaction using sequence specific primers (PCR-SSP) (Olerup SSP, Qiagen). A statistically significant increase in HLA-DRB1∗15 xx (23% vs. 8%) and HLA-DQB1∗06 xx (26.9% vs 8%,) was detected in Parsi patients as compared to controls. High resolution typing of HLA-DQB1∗06 xx amongst them showed a significant increase in DQB1∗06:09 (11.53% vs. 2%) OR = 7.2; Chi square = 2.86; p value 0.05, CI (0.82-73.29).[ Table 1 ] Dean and Wadia studied MS patients amongst Asian immigrants in England. Five Parsis were found with definite MS in a community of 5000, as compared to 23 amongst 383,000 ethnic Indian immigrants. It has been of some concern that our genetic analysis is in a small number of patients, but such is the cohort available from this tiny community, which is now spread worldwide. Earlier clinical data has shown small affected populations can yield valuable information that may reflect on broader issues of genetic susceptibility. So a higher frequency of DRB1∗15 and DQB1∗06 in MS patients with a statistically significant increase in the DQB1∗06:09 allele is detected.