Correlation of intestinal disaccharidase activities with the C/T-13910 variant and age.
OBJECTIVE
To correlate the C/T(-13910) variant, associated with lactase persistence/non-persistence (adult-type hypolactasia) trait, with intestinal disaccharidase activities in different age groups of the adult population.


METHODS
Intestinal biopsies were obtained from 222 adults aged 18 to 83 years undergoing upper gastrointestinal endoscopy because of unspecified abdominal complaints. The biopsies were assayed for lactase, sucrase and maltase activities and genotyped for the C/T(-13910) variant using PCR-minisequencing.


RESULTS
There was a significant correlation between lactase activity and the C/T(-13910) variant (P < 0.00001). The mean level of lactase activity among subjects with C/C(-13910) genotype was 6.86 +/- 0.35 U/g, with C/T(-13910) genotype 37.8 +/- 1.4 U/g, and with T/T(-13910) genotype 57.6 +/- 2.4 U/g protein, showing a trimodal distribution of this enzyme activity. Significant differences were also observed in maltase activities among individuals with different C/T(-13910) genotypes (P = 0.005). In contrast, in sucrase activity, no significant differences emerged between the C/T(-13910) genotypes (P = 0.14). There were no statistical differences in lactase (P = 0.84), sucrase (P = 0.18), or maltase activity (P = 0.24) among different age groups. In the majority (> 84%) of the patients with the C/C(-13910) genotype associated with lactase non-persistence, the lactase activity was less than 10 U/g protein.


CONCLUSIONS
Our study demonstrates a statistically significant correlation between the C/T(-13910) genotype and lactase activity and this correlation is not affected by age in adults but the cut-off value of 20 U/g protein used for the diagnosis of lactase non-persistence might be too high.
Department of Molecular Medicine, National Public Health Institute, Haartmaninkatu 8, PO Box 104, FIN-00251 Helsinki. nabil.enattah@ktl.fi
Nabil-Sabri
NS
Enattah
Mikko
M
Kuokkanen
Carol
C
Forsblom
Sirajedin
S
Natah
Aino
A
Oksanen
Irma
I
Jarvela
Leena
L
Peltonen
Erkki
E
Savilahti
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004186:Disaccharidases / Q000235:genetics* / Q000378:metabolism; D005838:Genotype; D006801:Humans; D007422:Intestines / Q000201:enzymology*; D043322:Lactase / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged
D004186:Disaccharidases; D043322:Lactase