title: Genetic testing improves the diagnosis of adult type hypolactasia in the Mediterranean population of Sardinia.
abstract: 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.
authors.affiliation: Biomedical Science and Biotechnologies, University of Cagliari, Via Jenner, Cagliari, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Schirru
authors.forename: V
authors.initials: V
authors.lastname: Corona
authors.forename: P
authors.initials: P
authors.lastname: Usai-Satta
authors.forename: M
authors.initials: M
authors.lastname: Scarpa
authors.forename: F
authors.initials: F
authors.lastname: Oppia
authors.forename: F
authors.initials: F
authors.lastname: Loriga
authors.forename: F
authors.initials: F
authors.lastname: Cucca
authors.forename: S
authors.initials: S
authors.lastname: De Virgiliis
authors.forename: R
authors.initials: R
authors.lastname: Rossino
authors.forename: M Doloretta
authors.initials: MD
authors.lastname: Macis
authors.forename: R-D
authors.initials: RD
authors.lastname: Jores
authors.forename: M
authors.initials: M
authors.lastname: Congia
mesh_terms: 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
chemical_list: D005819:Genetic Markers; D006859:Hydrogen; D043322:Lactase; D007785:Lactose