Consanguinity among Autistic individuals: Prevalence and Associations with Intellectual Disability and Epilepsy

Abstract

Background: Although autism is a global disorder, relatively little is known about the prevalence of consanguinity among autism spectrum disorder (ASD) individuals. Also, the relation of ASD comorbidities (Epilepsy and Intellectual Disability) to consanguinity have not been explored. Aims: We aim to estimate the global prevalence of consanguinity among the ASD individuals and compare it that among different populations. In addition, we aim document the prevalence of epilepsy and ID in relation to consanguinity in individuals diagnosed with ASD in Qatar and to assess the association between epilepsy and ID and consanguinity and other potential socio-demographic factors, environmental and other clinical factors. Methods: Meta-Analysis of observational studies reporting prevalence of consanguinity among ASD individuals from 8 countries 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. Random Effect model was used to calculate pooled weighted estimates due to considerable heterogeneity. Subgroup analysis was also calculated. Moreover, secondary data were analyzed using the cross-sectional study on profiles and correlates of ASD clinical sample in Qatar. Descriptive, univariable and multivariable analysis were conducted to estimate the prevalence of consanguinity, epilepsy and ID among ASD individuals in this cohort and assess association to other potential confounding determinants.

Results: The meta-analysis included 10 studies reporting prevalence of consanguinity among ASD cases. The pooled estimate of consanguinity among ASD cases was 24% (95%CI:17%-32%). Subgroup analysis by the study country led to a higher pooled estimate of consanguinity of 38% (95%CI:28%-49%) in the GCC countries compared to other than GCC countries with a pooled estimate of 16% (95%CI:11%-23%). The cross-sectional included a total of 171 ASD cases. Male to female ratio 4:1 and mean age was 13.5 years. Epilepsy was reported by 19%. ID reported by 83% of the cases. 76.6% were nonverbal. Eighty-three percent of the families had one proband, 9.9% had 2 probands, and 7.1% had more than two. The association between epilepsy and ID among ASD patients and consanguinity was not statistically significant (P value >0.05) controlling for other potential risk factors. Conclusion: The globally estimated pooled consanguinity prevalence among ASD patients was 24%, GCC countries showed a higher pooled prevalence (38%). The clinical sample used did not provide any evidence on association between both epilepsy and ID and consanguinity among ASD patients in Qatar. Further larger studies with much better large and representative sample may be required to confirm our results