Marta A.S. Arroyo, Ana Cláudia P. Lopes, Vania B. Piatto, José Victor Maniglia
Department of Otorhinolaryngology of Medical School of São José do Rio Preto, (FAMERP), São Paulo, Brazil, Av. Brigadeiro Faria Lima, nº 5416, Vila
São Pedro, São José do Rio Preto, SP, Zip Code: 15090-000, Brazil.
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For many years Lactose intolerance has been, considered as a universal problem in many children
The aim is to investigate the prevalence of polymorphism -13910C/T, in a neonatal tracking, for
early diagnosis of lactose tolerance/intolerance. Materials and Methods: In a cross-sectional study of 310 Brazilian
newborns, DNA was extracted from leukocyte umbilical cord and specific primers were used to amplify the region that
encloses the -13910C/T polymorphism of the MCM6 gene, using the polymerase chain reaction and the restriction
fragment length polymorphism tests.
One hundred and sixty (52%) male newborns and 150 (48%) female new
borns were evaluated. Out of these, 191 (62%) presented CC genotype (lactose intolerant), 95 (31%) CT genotype, and 24
(7%) TT genotype, comprising a total of 119 (38%) lactose tolerant newborns. Accordingly the newborns´ gender
distribution in relation to the phenotypes has been found; 97 (32%) of male gender and 94 (30%) of female gender lactose
intolerant, and 63 (20%) male and 56 (18%) female lactose tolerant newborns, not being such distribution statistically
significant (p = 0.801).
The molecular analysis made possible the identification of the presence or absence of
lactase persistence variant in the Brazilian newborns. The neonatal molecular diagnosis can optimize the follow-up of
positive results in newborn screening for lactose intolerance.