> Lactose intolerance in infants (congenital lactase deficiency) is caused by mutations in the LCT gene. > [....] Lactose intolerance in adulthood is caused by gradually decreasing activity (expression) of the LCT gene after infancy, which occurs in most humans.
> LCT gene expression is controlled by a DNA sequence [....] Some individuals have inherited changes in this element that lead to [....] the ability to digest lactose throughout life. People without these changes have a reduced ability to digest lactose as they get older, [....]
> [....] Lactose intolerance in adulthood is caused by gradually decreasing activity (expression) of the LCT gene after infancy, which occurs in most humans.