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.
We aimed to contrast rates of consanguinity among patients with bipolar I disorder (BP1) and controls in a population with customary consanguineous marriages (i.e., marriage between related individuals). Consanguinity increases risk for numerous monogenic and polygenic diseases. Whether the risk for BP1 increases with consanguinity has not been investigated systematically. Two independent studies were conducted in Egypt: (1) Case–control study 93 patients with BP1, 90 screened adult control individuals, and available parents. The inbreeding coefficient/consanguinity rate was estimated in two ways: using 64 DNA polymorphisms (“DNA-based” rate); and from family history data (“self report”); (2) Epidemiological survey: total of 1,584 individuals were screened, from whom self-reported consanguinity data were obtained for identified BP1 cases (n=35) and 150 randomly selected, unaffected control individuals. DNA-based consanguinity rates showed significant case–control control differences (P=0.0039). Self-reported consanguinity rates were also elevated among BP1 patients in both samples (Study #1 OR=2.66, 95% confidence intervals, CI: 1.34, 5.29; Study #2: OR=4.64, 95% CI: 2.01, 10.34). In conclusion, two independent, systematic studies indicate increased consanguinity among Egyptian BP1 patients in the Nile delta region. Self-reported estimates of consanguinity are bolstered by DNA-based estimates, and both show significant case–control differences for BP1.
The objective of the study is to screen 12 MEFV gene mutations in Egyptian patients with familial Mediterranean fever (FMF) and to study the initial hypothesis that the phenotypic expression of the disease may be attributable to the existence of a particular mutation. We enrolled 136 Egyptian patients (74 males, and 62 females) with a clinical diagnosis of FMF. DNA was amplified by PCR and subjected to reverse hybridization for the detection of 12 MEFV gene mutations. The phenotypic expression of the disease was compared in two subgroups according to the presence of homozygote E148Q and M694V gene mutations. The most frequent gene mutations in the studied group were V726A, M694V, M680I, E148Q and M694I in 41.2, 32.4, 29.4, 25 and 20.6%, respectively. At least one of these main five founder mutations was present in 132 patients (97.1%). Thirty-two patients (23.5%) were homozygote for one of the main five founder mutations. The most common homozygote gene mutations were E148Q and M694V, each in 12 patients (8.8%). Significant increase in abdominal pain and arthritis was found in patients with homozygote M694V mutation compared to those with E148Q mutation. All patients with amyloidosis had M694V gene mutation. The increased frequency of V726A gene mutation and the rarity of amyloidosis in this study suggest that Egyptian patients may have a milder form of FMF compared to other populations. The five main founder mutations account for the vast majority of cases of FMF. M694V gene mutation may be associated with increased frequency of abdominal pain, arthritis and the presence of amyloidosis.
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