RESUMO
BACKGROUND: To check the possible usefulness in studying DNA in dried blood spots taken on filter paper blotters for newborn identification. It set out to establish: 1. The validity of the method for analysis; 2. The validity of all stored samples (such as those kept in clinical records); 3. Guarantee of non-intrusion in the genetic code; 4. Acceptable price and execution time. MATERIAL AND METHODS: Forty (40) anonymous 13-year-old samples of 20 subjects (2 per subject) were studied. DNA was extracted using Chelex resin and the STR ("small tandem repeat") of microsatellite DNA was studies using the "polimerase chain reaction method" (PCR). Three non coding DNA loci (CSF1PO, TPOX and THO1) were analyzed by Multiplex amplification. RESULTS: It was possible to type 39 samples, making it possible to match the 20 cases (one by exclusion). The complete procedure yielded the results within 24 hours in all cases. The estimated final cost was found to be a fifth of that conventional maternity/paternity tests. CONCLUSIONS: The study carried out made matching possible in all 20 cases (directly in 19 cases). It was not necessary to study DNA coding areas. The validity of the method for analyzing samples stored for 13 years without any special care was also demonstrated. The technic was fast, producing the results within 24 hours, and at reasonable cost.
