Basic research Apolipoprotein E polymorphism is associated with susceptibility to schizophrenia among Saudis

Abstract

IntroductionApolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer's and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population.Material and methodsAPOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques.ResultsThe frequencies of the APOE allele ε2 and genotypes ε2/ε3 and ε2/ε4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE ε3 for schizophrenia. This study indicated that APOE ε4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the ε4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE ε4 and schizophrenia patients with negative symptoms was observed. Genotypes ε2/ε2 and ε4/ε4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE ε2/ε3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients.ConclusionsThe results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis.

Verbal memory improvement in first-episode psychosis <em>APOE-</em>&epsilon;4 carriers: a pleiotropic effect?

“…APOE -ε4 status was not associated with any outcome measures during the study or there was any difference in terms of premorbid illness measures such as duration of untreated psychosis, age of onset, and age at first decline. Given the hypothesis of antagonistic pleiotropy, APOE -ε4 in this young population appears not be associated with a detrimental effect, but our data do not replicate those finding less positive symptoms in APOE -ε4 carriers 46 , 47 but are convergent to findings from other groups. 48 – 50 In addition, our data provide further support to the association of cognitive performance and negative symptoms.…”

KLF1 gene and borderline hemoglobin A2 in Saudi population

“…Detailed analysis of the molecular nature of the α globin ( HBA1 and HBA2 ), β globin ( HBB ) and KLF1 genes on Saudis with various levels of HbA 2 revealed that the KLF1 gene or its variants was found to be not associated with the presence of borderline HbA 2 . The rate of consanguinity among Saudis is high [ 26 ]. Hence, precise identification of individuals with β globin gene variation is necessary for distinguishing couples at risk for having progeny with β-thalassemia major of sickle cell disease, especially considering the level of HbA 2 for the identification of β-thalassemia carriers.…”

APOE Gene polymorphism among Jordanian Alzheimer’s patients with relation to lipid profile

“…Comparing our results with non-Levant Arab communities, three different studies from Saudi Arabia showed the total absence of the ε2 allele in healthy Saudis. [15][16][17] Kuwaiti, Omani, and Iranians showed almost similar APOE genotype and allele distribution as the Jordanian volunteers in this study. [18][19][20] In addition, data from populations of the Mediterranean basin such as Turks, 21 Greeks, 22 and Sardinians 23 also showed a similar distribution of APOE alleles to that of Jordanians.…”