Table 5. [Comparison of HLA-B*15:02 and HLA-A*31:01 and Carbamazepine Therapy]. - Medical Genetics Summaries

	HLA-B15:02*	HLA-A31:01*
Associated phenotype	HLA-B15:02* is strongly associated with SJS/TEN	HLA-A31:01* is associated with all carbamazepine hypersensitivity phenotypes, including MPE, HSS, and (less strongly) SJS/TEN
Allele distribution	Predominantly concentrated in Southeast Asia, e.g., Hong Kong, Thailand, Malaysia, Vietnam, Philippines, Taiwan, Singapore.	Widely distributed across a range of populations including Europeans, Japanese, South Koreans and Han Chinese
Phenotype distribution	The strong association of HLA-B15:02* with carbamazepine-induced SJS/TEN is largely confined to individuals from Southeast Asian countries	HLA-A31:01* has been associated with carbamazepine-induced hypersensitivity reactions, particularly HSS, across different populations including European and Japanese individuals.
Pharmacogenetic screening recommendations	Screening for HLA-B15:02* is mandated in patients from Southeast Asia, prior to initiation of carbamazepine therapy. The FDA states that “patients with ancestry in genetically at-risk populations should be screened for the presence of HLA-B15:02* prior to initiating treatment with carbamazepine”.	Screening is not currently mandated prior to initiation of carbamazepine therapy. The FDA states that the “risks and benefits of carbamazepine therapy should be weighed before considering carbamazepine in patients known to be positive for HLA-A31:01*”.
Allele frequencies (reported by the FDA (1))	Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China. South Asians, including Indians, appear to have intermediate prevalence of HLA-B15:02, averaging 2% to 4%, but higher in some groups. HLA-B15:02 is present in less than 1% of the population in Japan and Korea. HLA-B1502* is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).	HLA-A31:01* is expected to be positive by more than 15% of patients of Japanese, Native American, South Indian (for example, Tamil Nadu) and some Arabic ancestry; up to about 10% in patients of Han Chinese, Korean, European, Latin American, and other Indian ancestry; and up to about 5% in African- Americans and patients of Thai, Taiwanese, and Chinese (Hong Kong) ancestry.

HLA-B*15:02

HLA-A*31:01

Associated phenotype

HLA-B*15:02 is strongly associated with SJS/TEN

HLA-A*31:01 is associated with all carbamazepine hypersensitivity phenotypes, including MPE, HSS, and (less strongly) SJS/TEN

Allele distribution

Predominantly concentrated in Southeast Asia, e.g., Hong Kong, Thailand, Malaysia, Vietnam, Philippines, Taiwan, Singapore.

Widely distributed across a range of populations including Europeans, Japanese, South Koreans and Han Chinese

Phenotype distribution

The strong association of HLA-B*15:02 with carbamazepine-induced SJS/TEN is largely confined to individuals from Southeast Asian countries

HLA-A*31:01 has been associated with carbamazepine-induced hypersensitivity reactions, particularly HSS, across different populations including European and Japanese individuals.

Pharmacogenetic screening recommendations

Screening for HLA-B*15:02 is mandated in patients from Southeast Asia, prior to initiation of carbamazepine therapy.
The FDA states that “patients with ancestry in genetically at-risk populations should be screened for the presence of HLA-B*15:02 prior to initiating treatment with carbamazepine”.

Screening is not currently mandated prior to initiation of carbamazepine therapy.
The FDA states that the “risks and benefits of carbamazepine therapy should be weighed before considering carbamazepine in patients known to be positive for HLA-A*31:01”.

Allele frequencies (reported by the FDA (1))

Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China.
South Asians, including Indians, appear to have intermediate prevalence of HLA-B*15:02, averaging 2% to 4%, but higher in some groups. HLA-B*15:02 is present in less than 1% of the population in Japan and Korea.
HLA-B*1502 is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).

HLA-A*31:01 is expected to be positive by more than 15% of patients of Japanese, Native American, South Indian (for example, Tamil Nadu) and some Arabic ancestry; up to about 10% in patients of Han Chinese, Korean, European, Latin American, and other Indian ancestry; and up to about 5% in African- Americans and patients of Thai, Taiwanese, and Chinese (Hong Kong) ancestry.

From: Carbamazepine Therapy and HLA Genotype

Medical Genetics Summaries [Internet].

Pratt VM, Scott SA, Pirmohamed M, et al., editors.

Bethesda (MD): National Center for Biotechnology Information (US); 2012-.

All Medical Genetics Summaries content, except where otherwise noted, is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license which permits copying, distribution, and adaptation of the work, provided the original work is properly cited and any changes from the original work are properly indicated. Any altered, transformed, or adapted form of the work may only be distributed under the same or similar license to this one.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.