title: Quality and quantity of DNA isolated from frozen urine in population-based research.
abstract: In several population-based studies in the past urine samples were collected and stored for future research. We set out to determine the reliability of using such samples for genotyping DNA markers in epidemiologic research. A source of DNA extracted from exfoliated nucleated cells in urine is provided by the DOM cohort, in which specimens were collected 15-25 years ago. We have examined the quality of the DNA in 48 of these samples by measuring the amount of DNA isolated and its ability to provide an adequate PCR template for amplicons of different lengths. MTHFR polymorphism was analyzed in 644 specimens to determine the inter- and intraobserver reproducibility. Although the DNA amount was variable, 26 to 89% of the samples, depending both on the length of the PCR amplicon and on PCR conditions, yielded a visible PCR product. The intra- and interobserver agreements were comparable (kappa 0.86 and 0.88, respectively). Our results demonstrate that frozen urine samples can be used for DNA typing studies in women after prolonged periods of storage, but with sometimes unpredictable results. Ultimately, the genotype success rate was 89.3%. Urine collection can be considered as a useful method of obtaining DNA in large cohort studies and other circumstances when blood samples cannot be obtained or have not been stored.
authors: Julius Center for General Practice and Patient Oriented Research, University Medical Center, 3508 GA Utrecht, The Netherlands. o.vanderhel@jc.azu.nl
authors: Olga L
authors: OL
authors: van der Hel
authors: Rob B
authors: RB
authors: van der Luijt
authors: H B
authors: HB
authors: Bueno de Mesquita
authors: Paul A H
authors: PA
authors: van Noord
authors: Barbara
authors: B
authors: Slothouber
authors: Mark
authors: M
authors: Roest
authors: Yvonne T
authors: YT
authors: van der Schouw
authors: Diederick E
authors: DE
authors: Grobbee
authors: Peter L
authors: PL
authors: Pearson
authors: Petra H M
authors: PH
authors: Peeters
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000652:urine*; D017931:DNA Primers; D004812:Epidemiologic Methods; D005260:Female; D005374:Filtration; D005615:Freezing; D005838:Genotype; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009426:Netherlands; D015588:Observer Variation; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D011110:Polymorphism, Genetic; D013048:Specimen Handling
chemical_list: D017931:DNA Primers; D004247:DNA; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)