Polymorphisms in the LCT gene

Primary shortage of lactase, an enzyme responsible for lactose decomposition is the most frequent cause of lactose intolerance. Typically, lactose intolerance develops during puberty and in adults. Without lactase, undigested lactose remains in intestines and undergoes the process of fermentation due to intestinal bacteria activity. Big amounts of gases are produced, which as a result, cause digestive issues.
Stomach pains, diarrhea, colic, flatulence, abdominal distension, bowel gurgling and belching are the most frequent symptoms of lactose intolerance. Symptoms can occur even after several hours after the consumption of products containing lactose. Lactose intolerance can also be temporary and result from destruction of gastric mucosa caused by some drugs or disorders, such as coeliac disease or giardiasis. This form of lactose intolerance is known as secondary lactose intolerance.

Polymorphisms rs4988235 and rs182549 are localized within the regulatory region of the LCT gene which encodes lactase – the enzyme involved in the lactose metabolism. Mutations occurring in the LCT gene are strongly associated with the development of primary lactose intolerance. Each of those polymorphisms has two allelic variants: A and G. The allelic variants rs4988235(G) and rs182549(G) encode dysfunctional versions of lactase which lead to hypolactasia.

Diagnostic kits AmpliSNiP LCT (qPCR) allow the analysis of the rs4988235 and rs182549 polymorphisms. RM reaction mixture of each kit contains two probes designed to bind specifically to the sequence containing a different nucleotide at the polymorphic site. FAM dye-labeled probe is complementary to the G nucleotide-containing sequence, while the HEX-dyed probe is complementary to the A nucleotide-containing sequence. The qPCR reaction is a duplex-type. The kit also includes positive controls (PC) which contain both versions of the assayed polymorphisms. They enable to control the correct course of the qPCR reactions.