title: Extreme high prevalence of a defective mannose-binding lectin (MBL2) genotype in native South American West Andean populations.
abstract: Mannose-binding lectin (MBL) is one of the five recognition molecules in the lectin complement pathway. Common variant alleles in the promoter and structural regions of the human MBL gene (MBL2) influence the stability and serum concentration of the protein. Epidemiological studies have shown that MBL2 variant alleles are associated with susceptibility to and the course of different types of infectious and inflammatory conditions. However, it has been suggested that these alleles are maintained in different populations due to selected advantages for carriers. We investigated the MBL2 allelic variation in indigenous individuals from 12 different West Central South America localities spanning from the desert coast, high altitude Andean plates and the Amazon tropical forest within the territories of Peru (n = 249) (Departments of Loreto, Ucayali, Lambayeque, Junin, Ayacucho, Huancayo and Puno), and Ecuador (n = 182) (Region of Esmeraldas and Santo Domingo de los Colorados). The distribution of MBL2 genotypes among the populations showed that the defective variant LYPB haplotype was very common. It showed the highest frequencies in Puno (Taquile (0.80), Amantani (0.80) and Anapia (0.58) islander communities of the Lake Titicaca), but lower frequencies of 0.22 in Junin (Central Andean highland) and Ucayali (Central Amazonian forest), as well as 0.27 and 0.24 in the Congoma and Cayapa/Chachis populations in the Amazonian forest in Ecuador were also observed. Our results suggest that the high prevalence of the MBL2 LYPB variant causing low levels of functional MBL in serum may mainly reflect a random distribution due to a population bottleneck in the founder populations.
authors.affiliation: Centro de Genética y Biología Molecular (CGBM), Facultad de Medicina Humana, Universidad San Martín de Porres, Lima, Perú
authors.forename: José Raul
authors.initials: JR
authors.lastname: Sandoval
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Section 7631, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Hans O
authors.initials: HO
authors.lastname: Madsen
authors.affiliation: Department of Biology, Universita Tor Vergata, Rome, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: De Stefano
authors.affiliation: Laboratorio de Genética Humana, Facultad de Biología, Universidad Nacional Mayor de San Marcos, Lima, Perú
authors.forename: Jaime
authors.initials: J
authors.lastname: Descailleaux-Dulanto
authors.affiliation: Laboratorio de Genética Humana, Facultad de Biología, Universidad Nacional Mayor de San Marcos, Lima, Perú
authors.forename: Margarita
authors.initials: M
authors.lastname: Velazquez-Reinoso
authors.affiliation: Universidad Catolica Santo Toribio de Mogrovejo, Facultad de Medicina Humana, Lambayeque, Perú
authors.forename: Cesar
authors.initials: C
authors.lastname: Ñique
authors.affiliation: Centro de Genética y Biología Molecular (CGBM), Facultad de Medicina Humana, Universidad San Martín de Porres, Lima, Perú
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fujita
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Section 7631, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Garred
mesh_terms: D000483:Alleles; D044467:American Indian or Alaska Native / Q000235:genetics*; D004198:Disease Susceptibility; D004484:Ecuador; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D037601:Mannose-Binding Lectin / Q000097:blood / Q000235:genetics*; D010568:Peru; D020641:Polymorphism, Single Nucleotide; D055503:Protein Multimerization
chemical_list: D037601:Mannose-Binding Lectin