Persistence of high intestinal lactase activity in Pakistan.

In order to determine the incidence of persistence of high intestinal lactase activity (PLA) in a Pakistani human population, 53 probands belonging to the Punjabi ethnic group were examined using a lactose tolerance test. The incidence of PLA in the sample was found to be 55%, which has been compared with the incidence in other ethnic groups racially or geographically related to the Pakistani population. Various possible explanations for the fairly high incidence of PLA in the Punjabi ethnic group have been discussed.