Influence of age, sex, and presence of cleft lip and palate on the quantity and quality of saliva-derived DNA

The quantity and quality of DNA are crucial factors in determining polymorphisms in samples from individuals with and without pathologies such as cleft lip and palate (CL/P). Saliva is increasingly being evaluated as a collection method. This study aimed to compare saliva DNA concentrations from individuals of different ages with and without CL/P.

Saliva samples were collected, DNA was extracted and the quantification was performed by spectrophotometry. Kruskal-Wallis test was used to compare frequencies between groups, and Spearman's rho for correlations.

We obtained saliva DNA from 314 individuals: 107 with CL/P (mean age: 12.7 ± 6.5 years), 103 parents of children with CL/P (mean age: 41.1 ± 9.3 years), 52 individuals without CL/P under 18 years old (controls), and 52 individuals without CL/P over 18 years old (controls). The sample comprised 32.2 % females and 67.8 % males.

Statistically significant differences in DNA concentrations were found between individuals under and over 18 years old (12.38 and 21.3 ng/μl, respectively, p = 0.0001), but no differences were observed between males and females. Individuals with CL/P had lower DNA concentrations (12.45 ng/μl) compared to their parents and controls (21.95 and 21.15 ng/μl, respectively). Our results showed a direct correlation between age and DNA concentration in individuals with CL/P under 18 years old (R = 0.328).