Allelic variations in the edar gene and their influence on hair types in Malaysian populations

• Main Author: Boon, Wendy Tan Lee
• Format: Thesis
• Language: English
• Published: 2025
• Subjects: R Medicine; RA1001 Forensic Medicine. Medical jurisprudence. Legal medicine
• Online Access: http://eprints.usm.my/63142/

Ectodysplasin A Receptor (EDAR) is a tumor necrosis factor receptor (TNFR) that is involved in the development of ectodermal tissues, including hair follicles. The single nucleotide polymorphism (SNP) rs3827760, which encodes EDAR:p.(Val370Ala), is a missense mutation in the EDAR gene that pleiotropically influences phenotypic traits such as hair type, particularly in East Asian populations. However, the genotype distribution and correlation of this SNP with hair type among Malaysian ethnic groups remain largely unexplored. Thus, this study aimed to determine the allelic variation of SNP rs3827760 in the Malaysian population among the Malay, Chinese, and Indian ethnic groups. DNA samples (buccal swabs) were collected from 30 participants, with 10 individuals from each ethnic group, and extracted using a silica-based solid-phase extraction (SPE) method. Polymerase chain reaction (PCR) was performed using the custom EDAR primers, followed by agarose gel electrophoresis, DNA quantification, cycle sequencing, and ethanol precipitation (purification). Sanger sequencing was conducted using the SeqStudio™ Genetic Analyzer, and the chromatograms were analyzed with Chromas and Jalview software to identify nucleotide variations at the SNP loci rs3827760, rs146567337, and rs12623957. A chi-square test was performed to determine the statistical significance of the association between the SNPs and ethnicity or hair type. The analysis showed that SNP rs3827760 was significantly correlated with both ethnicity (P-value <0.001) and hair type (P-value = 0.011). The ancestral allele (allele A) was strongly associated with Indian (curly hair) individuals, while the derived allele (allele G) was strongly associated with Chinese (straight hair) individuals. Malay individuals with straight or wavy hair exhibited a mix of all three genotypes. SNP rs146567337 showed no significant association with ethnicity (P-value = 0.155) or hair type (P-value = 0.432). SNP rs12623957 was not significantly related to ethnicity (P-value = 0.058) but was correlated with hair type (P-value = 0.017). Therefore, SNP rs3827760 in the EDAR gene was the most strongly correlated genetic factor for hair types and ethnicity in this study