What Is Known About The Genetic Cause Of Congenital Lactase Deficiency?
In 2006, a team of mostly Finnish molecular geneticists reported the discovery of five distinct mutations in a gene that is designated LCT in the genomes of several infants who were diagnosed as having CLD. Specifically, the normal, non-mutated version of LCT gene encodes the protein lactase. Lactase, which is synthesized in cells that line the small intestine, catalyzes the break down of lactose into the simpler sugars glucose and galactose, which are capable of being absorbed into the bloodstream (whereas, lactose, which is a much larger molecule, is not).
Infants who have mutations in each one of their two copies of the LCT gene are unable to make lactase, or make a highly defective version of the lactase protein, and therefore are unable to break down lactose in their small intestine. The resulting build up of lactose is problematic for the small intestine, which is why the gastrointestinal problems described above are seen.
If your baby is experiencing the problems described above and you suspect that she may be suffering from CLD (again, CLD is a very rare condition, so it is unlikely that your child has CLD), it is recommended that you consult your doctor, who can positively diagnose the problem that your child is suffering from. This article is meant only to provide some background information regarding congenital lactose deficiency, it is not meant to replace the sound advice of your doctor.