Molecularly defined adult-type hypolactasia in school-aged children with a previous history of cow's milk allergy.

AIM: To assess the role of lactase non-persistence/persistence in school-aged children and their milk-related symptoms.

METHODS

The genotypes for the C/T(-13910) variant associated with lactase non-persistence/ persistence were determined using PCR-minisequencing in a group of 172 children with a mean age of 8.6 years (SE = 0.02, 93 boys) participating in a follow-up study for cow's milk allergy. The parents were asked to assess their children's milk consumption and abdominal symptoms.

RESULTS

The presence of allergy to cow's milk was not associated with the C/C(-13910) genotype related with a decline of lactase enzyme activity during childhood (lactase non-persistence). The frequency of the C/C(-13910) genotype (16%) was similar to published figures for the prevalence of adult-type hypolactasia in Finland. The majority of the children (90%) in this series consumed milk but 26% of their families suspected that their children had milk-related symptoms. Forty-eight percent of the children with the C/C(-13910) genotype did not drink milk at all or consumed a low lactose containing diet prior to the genotyping (P < 0.004 when compared to the other genotypes).

CONCLUSION

Analysis of the C/T(-13910) polymorphism is an easy and reliable method for excluding adult-type hypolactasia in children with milk-related symptoms. Genotyping for this variant can be used to advise diets for children with a previous history of cow's milk allergy.