Decline of lactase activity and c/t-13910 variant in Sardinian childhood.
OBJECTIVE
Our study aims to determine the age of onset of adult-type hypolactasia in Sardinians, and to establish the age at which genotyping of the C/T-13910 variant can be used reliably in the diagnosis of lactose malabsorption.


METHODS
A lactose breath hydrogen test was given to 383 randomly selected patients, from 3 to 19 years old.


RESULTS
The C/C-13910 genotype was found in 90% of patients; the frequency of the positive lactose breath hydrogen test increased with age and reached a prevalence of 85% at 9 years.


CONCLUSIONS
In Sardinians, adult-type hypolactasia becomes phenotypically evident in all individuals older than 9 years, suggesting that this should be considered the minimum age at which the genetic test for lactase nonpersistence should be applied.
Schirru
Enrico
E
Department of Pediatric Science and Clinical Medicine, University of Cagliari, Cagliari, Italy. schirrue@yahoo.it
Corona
Valeria
V
Usai-Satta
Paolo
P
Scarpa
Maria
M
Cucca
Francesco
F
De Virgiliis
Stefano
S
Rossino
Rossano
R
Frau
Fulvia
F
Macis
Maria Doloretta
MD
Jores
Rita-Désirée
RD
Congia
Mauro
M
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D001944:Breath Tests; D002648:Child; D002675:Child, Preschool; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D006859:Hydrogen; D007558:Italy / Q000453:epidemiology; D043322:Lactase / Q000235:genetics* / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D007789:Lactose Tolerance Test; D007792:Lactulose / Q000378:metabolism; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015995:Prevalence
D007792:Lactulose; D006859:Hydrogen; D043322:Lactase; D007785:Lactose