Filaggrin Gene Mutations in Asian Races

Abstract

A total of 51 null mutations (28 nonsense mutations, 19 frameshift mutations, and 4 insertion mutations) in the filaggrin gene (FLG) have been identified in individuals with ichthyosis vulgaris, atopic dermatitis, or asthma from seven Asian populations (Japanese, mainland Chinese, Singaporean Chinese, Taiwanese, Korean, Pakistani, and Bangladeshi). The FLG mutation landscape in Asian individuals not only is different from European populations but also varies from each other. Thirty-nine (76.5 %) of 51 mutations are population-specific or family-specific. The mutation 3321delA has been found and demonstrated to be prevalent in five Asian populations (Japanese, Singaporean Chinese, mainland Chinese, Taiwanese, and Korean). In addition, the mutations S2554X, S2889X, and S3296X are common and specific to the Japanese; the relatively more prevalent mutations among Singaporean Chinese are G323X, S1515X, c.6950_6957del8, Q2417X, and E2422X. Another common mutation in mainland Chinese is K4671X, which was named as K4021X with a lower frequency in Japanese. Of note, two prevalent mutations (2282del4 and R501X) among European population were also prevalent in Bangladeshi and Pakistani, who share a common lineage with Europeans. This chapter reviews the spectrum of FLG mutations among seven Asian populations.