Molecular genetics of human lactase deficiencies.
Lactase non-persistence (adult-type hypolactasia) is present in more than half of the human population and is caused by the down-regulation of lactase enzyme activity during childhood. Congenital lactase deficiency (CLD) is a rare severe gastrointestinal disorder of new-borns enriched in the Finnish population. Both lactase deficiencies are autosomal recessive traits and characterized by diminished expression of lactase activity in the intestine. Genetic variants underlying both forms have been identified. Here we review the current understanding of the molecular defects of human lactase deficiencies and their phenotype-genotype correlation, the implications on clinical practice, and the understanding of their function and role in human evolution.
Järvelä
Irma
I
Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland. irma.jarvela@kolumbus.fi
Torniainen
Suvi
S
Kolho
Kaija-Leena
KL
D000328:Adult; D002648:Child; D015536:Down-Regulation; D005387:Finland; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D006801:Humans; D043322:Lactase / Q000172:deficiency / Q000235:genetics*; D007787:Lactose Intolerance / Q000235:genetics*; D008967:Molecular Biology; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide
D043322:Lactase