Frequency of LCT -13910C>T single nucleotide polymorphism associated with adult-type hypolactasia/lactase persistence among Brazilians of different ethnic groups.
BACKGROUND
Adult-type hypolactasia, the physiological decline of lactase some time after weaning, was previously associated with the LCT -13910C>T polymorphism worldwide except in Africa. Lactase non-persistence is the most common phenotype in humans, except in northwestern Europe with its long history of pastoralism and milking. We had previously shown association of LCT -13910C>T polymorphism with adult-type hypolactasia in Brazilians; thus, we assessed its frequency among different Brazilian ethnic groups.


METHODS
We investigated the ethnicity-related frequency of this polymorphism in 567 Brazilians [mean age, 42.1 +/- 16.8 years; 157 (27.7%) men]; 399 (70.4%) White, 50 (8.8%) Black, 65 (11.5%) Brown, and 53 (9.3%) Japanese-Brazilian. DNA was extracted from leukocytes; LCT -13910C>T polymorphism was analyzed by PCR-restriction fragment length polymorphism.


RESULTS
Prevalence of the CC genotype associated with hypolactasia was similar (57%) among White and Brown groups; however, prevalence was higher among Blacks (80%) and those of Japanese descent (100%). Only 2 (4%) Blacks had TT genotype, and 8 (16%) had the CT genotype. Assuming an association between CC genotype and hypolactasia, and CT and TT genotypes with lactase persistence, 356 (62.8%) individuals had hypolactasia and 211 (37.2%) had lactase persistence. The White and Brown groups had the same hypolactasia prevalence (approximately 57%); nevertheless, was 80% among Black individuals and 100% among Japanese-Brazilians (P < 0.01).


CONCLUSIONS
The lactase persistence allele, LCT -13910T, was found in about 43% of both White and Brown and 20% of the Black Brazilians, but was absent among all Japanese Brazilians studied.
Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, SP, Brazil. rejane-mattar@ig.com.br
Rejane
R
Mattar
Maria S
MS
Monteiro
Cibele A
CA
Villares
Aníbal F
AF
Santos
Joyce M K
JM
Silva
Flair J
FJ
Carrilho
D000328:Adult; D044466:Asian People / Q000235:genetics; D044383:Black People / Q000235:genetics; D001938:Brazil; D005006:Ethnicity / Q000235:genetics; D005260:Female; D006801:Humans; D007564:Japan / Q000208:ethnology; D043322:Lactase / Q000235:genetics*; D007787:Lactose Intolerance / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics
D043322:Lactase