Genotype Study of Filaggrin Gene Loss-of-Function Mutations in Central India Population with Atopic Dermatitis and Ichthyosis Vulgaris

BACKGROUND: A genotype study of filaggrin gene loss-of-function mutations in central India can provide valuable insights into the prevalence and association of these mutations with atopic dermatitis (AD) and ichthyosis vulgaris (IV) in the region. The FLG R501X and 2282del4 are both genetic variants in the human gene called filaggrin gene (FLG), which encodes a protein that plays an important role in the formation and maintenance of the skin barrier. In this study, we determined the FLG R501X and 2282del4 variants association with both AD and IV in Central Indian populations. MATERIALS AND METHODS: This case–control study was conducted in the Departments of Dermatology and Molecular and Virology Research and Diagnostic Laboratory at Sri Aurobindo Medical College and Post Graduate Institute, Indore (Madhya Pradesh). The study was approved by the Clinical Research and Ethics Committee. A total of 180 patients aged between 3 months - 60 years who attended the skin outpatient department between March-2021 to June-2022 were recruited in this study. Among them, 60 patients were in AD-group, 60 patients in IV-group, and 60 patients were in the healthy control group. Polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) was used in genotyping for FLG mutations (R501X and 2282del4). RESULTS: The most common FLG mutations were R501X (31.6% and 23.3%) and 2282del4 (18.3% and 13.3%) in AD and IV patients with heterozygous (AT) genotype, respectively. The combined mutation (FLG R501X and 2282del4) association was 10% and 5% in the AD and IV groups with heterozygous (AT) genotype, respectively, and in all the patients of control group with wild genotype (AA). There were no significant (P = 0.09) associations found with 2282del14 genotype. CONCLUSION: The R501X mutation in the gene encoding filaggrin is one of the robust genetic associations of AD and IV. The 2282del4 polymorphism was marginally less as compared to R501X.