Consanguinity and genetic diseases in Brazil: an overview

Consanguineous marriages have been practiced for thousands of years in many communities throughout the world. Birth defects contribute significantly to infant mortality rate (IMR), and they may be associated with consanguinity. Therefore, the objective of this review is to compile an overview of the findings on consanguinity and genetic diseases in the population of Brazil. We collect data from PubMed (January 2000 to July 2020), and data from the Modell Global Database of Congenital Disorders (MGDb) estimates for 2010-2014 in the Americas. The PubMed database yielded 199 results that met the inclusion/ exclusion criteria search. We observe a higher risk ratio (RR: 4.16, 95% CI 4.07-4.25) for consanguineous marriages compared with two other Brazilian studies. The highest coefficient of consanguinity was found in the city of Lagoa (F = 0.01182), state of Paraíba. In the same period (2010-2014), the coefficient of consanguinity was 0.0027, while the IMR was 20.3/1,000 live births in Brazil. The Kruskal-Wallis test used to compare Brazil and others country’s estimates was also statistically significant (H = 73.55, p<0.0001). Fifteen genetic diseases associated with consanguinity have been observed. Among these, a new mutation in pycnodysostosis disease (#265800, CTSK gene, c.953G>A), and Raine syndrome (#259775, FAM20C, c.1487C>T; p.P496L) are the diseases that stand out. With these results, we believe that the public health system should be working directly with the local communities in actions that include the creation of banks of genes/mutations related to consanguineous couples, neonatal screening and health education.