Analyzing Inbreeding and Estimating Its Related Deficiencies in Northeastern Brazil

This cross-sectional study aimed to observe number of marriages between relatives in São Francisco Valley municipalities and correlations between degrees of kinship and susceptibility to genetic diseases. Three hundred and nine (309) consanguineous couples were interviewed in five municipalities. The data were analyzed using SPSS (version 22), Chi-square testing, and the generalized estimating equation (GEE). In Pariconha-AL for first cousins, the results revealed significantly higher numbers of disabled children than for third cousins ( p  < 0.05). Of these, the prevalence for physical disability was significant ( χ 2 = 19.203, d f  = 4, p  = 0.001). In the cities of Glória-BA ( χ 2 = 11.652, d f  = 3, p  = 0.020) and OlhoD'água do Casado-AL ( χ 2 = 8.123, d f  = 4, p  = 0.044), physical disabilities were also significantly higher in children from unions of first-degree cousins than for other degrees of kinship. Visual impairment was more significant in first-degree cousins in Glória-BA ( χ 2 = 14.206, d f  = 3 p  = 0.007); yet among third-degree cousins, visual impairment in the municipality of Santa Brígida-BA was more prevalent ( χ 2 = 6.416, d f  = 2 p  = 0.040). Inbreeding, as revealed in the evaluated cities, reinforces the hypothesis for developing genetic diseases.