Consanguinity and increased risk for schizophrenia in Egypt

Abstract

Background Consanguinity has been suggested as a risk factor for psychsoses in some Middle Eastern countries, but adequate control data are unavailable. Our recent studies in Egypt have shown elevated parental consanguinity rates among patients with bipolar I disorder (BP1), compared with controls. We have now extended our analyses to Schizophrenia (SZ) in the same population. Methods A case-control study was conducted at Mansoura University Hospital, Mansoura, Egypt (SZ, n = 75; controls, n = 126, and their available parents). The prevalence of consanguinity was estimated from family history data (‘self report’), followed by DNA analysis using short tandem repeat polymorphisms (STRPs, n = 63) (‘DNA-based’ rates). Results Self reported consanguinity was significantly elevated among the patients (SZ: 46.6%, controls: 19.8%, OR 3.53, 95% CI 1.88, 6.64; p = 0.000058, 1 d.f.). These differences were confirmed using DNA based estimates for coefficients of inbreeding (inbreeding coefficients as means ± standard error, cases: 0.058 ± 0.007, controls: 0.022 ± 0.003). Conclusions Consanguinity rates are signifcantly elevated among Egyptian SZ patients in the Nile delta region. The associations are similar to those observed with BP1 in our earlier study. If replicated, the substantial risk associated with consanguinity raises public health concerns. They may also pave the way for gene mapping studies.

The Impact of Consanguinity on Risk of Schizophrenia

“…The rate of parental consanguinity (43.8 vs. 38%) and the mean coefficient of inbreeding (0.0198 ± 0.29 vs. 0.015 ± 0.24) was higher among Sz patients compared to subjects without Sz (table 1). Similar to our results, a significant elevated rate of consanguinity was observed among Sz patients in Egypt [5]. The present study has confirmed that consanguinity contributes to a high incidence of Sz in offspring.…”

Inbreeding is associated with lower 2D: 4D digit ratio

“…Historically, medical concerns about the deleterious effects of more closely inbred marriages have focused on the risk posed by recessive Mendelian traits, with much less attention to complex disorders and continuous traits (Bittles and Black, 2010). Among the few examples of complex traits however is good, casematched DNA-backed, evidence for an elevated risk for some psychiatric disorders among individuals with consanguineous parentage (Mansour et al, 2009(Mansour et al, , 2010. There appear to be some positive health outcomes associated with consanguineous marriages, such as higher fertility (reviewed in Bittles et al, 1991).…”

Mental health issues of Maria I of Portugal and her sisters: the contributions of the Willis family to the development of psychiatry

“…More recent studies have confirmed these findings and shown that consanguinity is a risk factor for cardiovascular disease (Shami, Qaisir and Bittles, 1991), bipolar disorder 1 (Mansour et al, 2009), schizophrenia (Mansour et al, 2010) and Alzheimer disease (Farrer et al, 2002). These results may be relevant to the high prevalence of mental and cardiovascular disorders in the Habsburg-Bourbon-Braganzas of Portugal.…”