Genetic Susceptibility to Carbamazepine Induced Cutaneous Adverse Drug Reactions

Abstract

Asia is a large region with 60% of world population. The region is the home of many national groups with different culture and ethnicity. Data from the WHO Uppsala Monitoring Center (WHO-UMC) and Novartis CBZ-SJS/TEN reports 2000-2006 showed that the incidence of ACDR induced by CBZ was high among some Asian countries. The incidence is not known in many geographical regions and ethnic groups. Therefore it is important to document the incidence of ACDR induced by CBZ in these areas. The importance of HLA-B*1502 as marker of CBZ-induced SJS/TEN is being established particularly among Han Chinese, and the prevalence of HLA-B*1502 in various ethnic groups are being determined, there are still large parts of Asia where the prevalence of HLA-B*1502 is not known. This is for example, the Han and non-Han Chinese from different parts of China, Filipinos, various ethnic groups in Indonesia, Pakistan, Bangladesh, Myanmar, Cambodia and Lao PDR. The determination of the prevalence of HLA-B*1502 in these ethnic groups is thus of high priority. The significance of HLA-B*1502 as a marker for CBZ-induced SJS/TEN is only established among the Han Chinese, less so among the Malays and Thais. As HLA-B*1502 as a marker of CBZ-induced SJS/TEN is ethnicity specific, the present study enlightens our knowledge about the relationship between HLA-B*1502 and CBZ-induced SJS/TEN in South India. There are many unanswered questions in CBZ induced ACDR and HLA-B*1502 waiting to be explored like the role of other HLA-B subtypes in CBZ induced SJS/TEN, significance of HLA-B*1502 and other HLA subtypes in ACDR induced by other antiepileptic drugs, e.g. phenytoin and lamotrigine. CONCLUSIONS: There is a high prevalence HLA-B*1502 allele in South Indian epileptic population on Carbamazepine (18.20%) when compared to the non-epileptic population (7%). This is being reported for the first time in the world literature and further studies have to be done in other centers in India and in other countries in different races to look for this difference.