(3) Several different interactions of the SYTL3–SLC22A3 SNP–SNP/environment, gene–gene/environment, and haplotype–haplotype/environment on the risk of HLP were found in the Han and Maonan ethnic groups, and gene plays a dominant role in the interactions in the Han ethnic group, but environmental factor (BMI > 24 kg/m2) plays a dominant role in the interactions in the Maonan ethnic group. Here, SLC22A3 is linked to hyperkeratosis lenticularis perstans.