Genetic testing improves the diagnosis of adult type hypolactasia in the Mediterranean population of Sardinia.
OBJECTIVE
Recently, the C/T-13910 polymorphism on chromosome 2q21 in North-European populations has been found completely associated with lactase activity and its genetic typing proposed as first-stage screening test for adult hypolactasia. However, the C/T-13910 variant in some sub-Saharan African groups is not a predictor of lactase persistence. In this work, we wanted to verify if in the Mediterranean island of Sardinia, located in Southern Europe, the C/T-13910 polymorphism may be useful or not for the diagnosis of adult type hypolactasia.


METHODS
Validation study of a genetic testing for adult type hypolactasia in Sardinians.


METHODS
Brotzu Hospital and Microcitemico Hospital, Cagliari, Italy.


METHODS
The sample consisted in 84 Sardinian individuals (63 women and 21 men; range 20-73 years) selected from a group of 832 patients.


METHODS
Genetic testing was compared to an improved test obtained by a combination of different breath hydrogen tests and clinical assessment.


RESULTS
We found that all 49 individuals with lactose malabsorption, demonstrated by a combination of different breath hydrogen tests and clinical assessment, carried the C/C-13910 genotype associated with lactase non-persistence, 23 individuals with lactose normal absorption carried the C/T-13910 genotype associated with lactase persistence and only one person with the above phenotype showed a discordant C/C-13910 genotype. The genetic testing showed very high sensitivity, specificity, positive and negative predictive values of 100, 95.8, 98 and 100%, respectively.


CONCLUSIONS
Sardinians, unlike some ethnic groups in sub-Saharan Africa, show the same genetic association of hypolactasia with the C/T-13910 variant as other North-European populations. The genetic testing for the C/T-13910 variant may contribute to improving the diagnosis of adult type hypolactasia.
Schirru
E
E
Biomedical Science and Biotechnologies, University of Cagliari, Via Jenner, Cagliari, Italy.
Corona
V
V
Usai-Satta
P
P
Scarpa
M
M
Oppia
F
F
Loriga
F
F
Cucca
F
F
De Virgiliis
S
S
Rossino
R
R
Macis
M Doloretta
MD
Jores
R-D
RD
Congia
M
M
D000328:Adult; D000368:Aged; D001944:Breath Tests; D002889:Chromosomes, Human, Pair 2; D003937:Diagnosis, Differential; D005260:Female; D005819:Genetic Markers; D005820:Genetic Testing / Q000379:methods / Q000592:standards*; D005838:Genotype; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D007422:Intestines / Q000201:enzymology; D007558:Italy / Q000453:epidemiology; D043322:Lactase / Q000172:deficiency* / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D007789:Lactose Tolerance Test; D008297:Male; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length; D011237:Predictive Value of Tests; D015995:Prevalence; D012680:Sensitivity and Specificity; D044465:White People / Q000235:genetics
D005819:Genetic Markers; D006859:Hydrogen; D043322:Lactase; D007785:Lactose