Studio dello spettro mutazionale del gene lattasi nell’intolleranza ereditaria al lattosio (ipolattasia dell’adulto)

AUTHORS

ABSTRACT

Study of the mutational spectrum of lactase gene in the inherited lactose intolerance (adult-type hypolactasia)

“Lactose intolerance” describes disorders related to the inability to digest dietary lactose, due to a deficiency of the lactase-phloridzin hydrolase (LPH). In humans, unlike all other mammals, the LPH enzyme undergoes after weaning a down-regulation of its activity, a condition known as “not persistence of lactase” (NLP). There are, however, some individuals who retain the ability to digest milk and dairy products into adulthood, showing the phenotype of the “lactase persistence” (LP). In Caucasians, this phenotype is associated to genetic C/T(-13910) and G/A(-22018) single nucleotide polymorphisms (SNPs). The NLP condition is characterized by remarkable phenotypic variability and considered to be a heterogeneous and multifactorial condition, linked to genetic factors and environmental variables.
Our study evaluated the frequency of C/T(-13910) and G/A(-22018) SNPs and of the lactase gene (LCT) mutations in a group of young individuals. The frequency of the two SNPs was comparable to that present in literature, while the LCT mutation analysis identified 4 polymorphisms, two missense mutations and some intronic substitutions, distant from the splice sites. We identified the allelic variants in silico and the subsequent analysis showed no significant changes in the aminoacidic sequence of the protein such as to justify the different phenotypic expression of lactose intolerance.

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