BACKGROUND: The availability of direct-to-consumer personalized genetic testing has enabled the public to access and interpret their own genetic information. Various genetic traits can be determined including resistance to norovirus through a nonsense mutation (G428A) in the FUT2 gene. Although this trait is believed to confer resistance to the most dominant norovirus genotype (GII. https://www.markymarkscott.com/product-category/tonucia-densifying-shampoo/