¹Department of Physiology, Instituto Nacional de Cardiologia "Ignacio Chávez", México City, México

²Department of Hematology, Instituto Nacional de Cardiologia "Ignacio Chávez", México City, México

³Molecular Biology and Immunogenetics Laboratory, Infectious Diseases Unit, Instituto Nacional de Enfermedades Respiratorias, México City, México

⁴Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Medicas y Nutrición Salvador Zubirán, México City, México

Correspondence to: Dr G Vargas-Alarcón, Department of Physiology, Instituto Nacional de Cardiología Ignacio Chávez. Juan Badiano No. 1, Tlalpan 14080, México D.F, México. E-mail: gvargas63@yahoo.com

This work was supported in part by grants from the Consejo Nacional de Ciencia y Technología. México D.F., México.

Low molecular weight polypeptide (LMP) genes are located within the major histocompatibility complex and have been associated with autoimmune diseases such as ankylosing spondylitis. In order to define the distribution of LMP genes in Mexican populations, the LMP2 and LMP7 polymorphism was analyzed in 312 Mexican individuals (95 Mexican Mestizos, 48 Nahuas, 56 Mazatecans, 50 Teenek, and 63 Mayos) belonging to different ethnic groups. In Mexican populations both Mestizos and Amerindians presented similar distribution of LMP2 and LMP7 polymorphisms, except Nahuas and Mayos who presented the higher frequencies of LMP2-H/H and the lowest frequencies of LMP2-H/R genotypes (P < 0.05 when compared with Mexican Mestizos). The LMP7-K/K genotype was absent in Nahuas, Teenek and Mayos and only one Mazatecan individual presented this genotype. Differences with other populations were found in Mexicans. An increased frequency of LMP2-H and a decreased frequency of LMP2-R alleles were observed in Mexican Amerindians (Nahuas and Mayos) when compared with Brazilian Amerindians (Kaingang and Guarani) and Caucasians (Spaniards) (P < 0.05). All Mexican populations (Mestizos and Amerindians) presented an increased frequency of LMP7-Q allele and a decreased frequency of LMP7-K allele when compared to Brazilian Amerindians (Kaingang), Caucasians (United States) and Asian (Japan) populations (P < 0.05). Genetic distances showed that Mexican Mestizos have an important relation with Spaniards and with all Mexican Amerindians. The present data corroborate the influence of Spaniard and Amerindian genes in the Mexican Mestizo population and could help to define the true significance of LMP polymorphism as genetic and evolutive marker in the Amerindian populations.

Genes and Immunity (2002) 3, 373-377. doi:10.1038/sj.gene.6363855

low molecular weight polypeptides; major histocompatibility complex; polymorphism; Mexican ethnic groups