Genetic defect and Lactase deficiency

Genetic defect noun - A disease or disorder that is inherited genetically.

Lactase deficiency and genetic defect are semantically related. In some cases you can replace phrase "Lactase deficiency" with "Genetic defect", this phrases are similar.

Lactase deficiency noun - Congenital disorder consisting of an inability to digest milk and milk products; absence or deficiency of lactase results in an inability to hydrolyze lactose.

Genetic defect and lactase deficiency are semantically related. You can use "Genetic defect" instead a noun phrase "Lactase deficiency".