Prevalence of consanguinity among ASD individuals: Systematic Review and Meta-analysis

Abstract

Aim:We aim to estimate the global prevalence of consanguinity among the ASD families and compare it that among different populations. Methods:Meta-Analysis of observational studies reporting prevalence of consanguinity among ASD families were searched systematically in important databases including EMBASE, PubMed and Academic Search Complete. Individual studies were screened by two reviewers independently, extracted data and assessed the risk of bias using a risk of bias tool (Hoy's tool). Random Effect model was used to calculate pooled weighted estimates due to considerable heterogeneity. Subgroups analysis was also calculated. Results:10 publications were identified based on our inclusion criteria from 8 different countries, 4 of them were from the Gulf Cooperation Council (GCC) and the rest were from: Lebanon (2 studies), Egypt, Jordan, Iran, and Israel). Studies varied in ASD cases numbers as it ranged between 49 -500, and the total ASD individuals in all studies were 1581. All studies address consanguinity among the ASD families despite the variation in the methods. The pooled estimate of consanguinity among ASD families was 24% Subgroup analysis by the study country led to a higher pooled estimate of consanguinity of 38% in the GCC countries compared to other than GCC countries with a pooled estimate of 16%. Also, the overall odd ratio calculated from the case-control studies included in our meta-analysis was 1.5. Discussion:To our knowledge, this is the first meta-analysis that studied the prevalence of consanguinity among ASD families worldwide. Children born to consanguineous parents have been reported to have lower social behavior and cognitive ability, which are the main problems with ASD children. Our study qualitatively reviewed the prevalence of consanguinity among ASD families throughout the world and 10 eligible studies from eight countries were identified. We quantitatively synthesized the results and the key findings of this study showed a 24% overall pooled estimate of consanguinity among ASD families. GCC countries showed a high estimated pooled prevalence of consanguinity among ASD families as 38% compared to countries other than GCC 16%, which was higher than our overall pooled prevalence. This high estimate among GCC countries can be related to the high rates of consanguineous marriage in the GCC countries compared to the worldwide rates (20%). In Qatar the rate of consanguineous marriage reported as 54%. This high rates among GCC countries may be due to factors like rooted cultural beliefs, social life and customs in addition to, economic benefits of keeping wealth within the families.Conclusion:The globally estimated pooled consanguinity prevalence among ASD patients was 24%, GCC countries showed a higher pooled prevalence (38%).