google "endogamous population genetic disorders" - I could easily paste a dozen more citations here...
https://www.sciencedirect.com/science/article/pii/S111086301...
"Conclusion
The present study revealed a higher incidence of certain diseases in consanguineous population with a high significant increase in the prevalence of common adult diseases such as diabetes mellitus, cancer, blood disorders, mental disorders, heart diseases, asthma, gastro-intestinal disorders, hypertension, hearing deficit, G6PD and common eye diseases. This confirms the role of genetic factors across the full spectrum of disease and not only for Mendelian disorders."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666836/
A positive correlation between inbreeding and numerous health outcomes has been reported in several studies. Indeed, unions between relatives are generally associated with an increased risk of abortions, stillbirths (Al-Awadi et al. 1986; Hussain 1998, 1999; Hussain et al. 2001), perinatal mortality (Stoltenberg et al. 1999), and congenital malformations (Abdulrazzaq et al. 1997; Chéhab et al. 2006; Yunis et al. 2006).
Consanguineous marriages are also recognized as being associated with higher risk for autosomal recessive diseases than in the general population (Taillemite et al. 1985; Alwan and Modell 1997; Kumaramanickavel et al. 2002) by favoring the expression of recessive deleterious alleles. Many reports have highlighted a positive association between inbreeding and a number of recessive single gene disorders like achromatopsia (Tchen et al. 1977), Leber's congenital amaurosis, xeroderma pigmentosum (Mokhtar et al. 1998), and metabolic defects like aminoacidopathies and mucopolysaccharidoses (Jaouad et al. 2009). However, some authors believe that a long practice of inbreeding over several generations leads to the elimination of deleterious recessive mutations from the population gene pool (Khoury et al. 1987).