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Children of first-cousin couples at higher risk for mood disorders, psychoses
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Children born to consanguineous parents are more likely to have common mood disorders and psychoses than those born to nonrelated parents, according to study findings published in JAMA Psychiatry.
“Although not common practice in the Western world (< 1% marriages) approximately one in 10 children worldwide are born to consanguineous parents. It is legal in all countries worldwide except the United States of America, North Korea and China. However, with increased migration we are seeing an increase in communities who practice consanguineous marriage across Western Europe,” Aideen Maguire, PhD, of Center for Public Health at Queen’s University Belfast in the U.K., told Healio Psychiatry. “Cousin marriage is associated with an increased risk of autosomal recessive genetic disorders in offspring but the association between cousin marriage and the mental health of offspring has not been extensively studied.”
The investigators conducted a retrospective population-wide cohort study of 363,960 people born in Northern Ireland from 1971 to 1986 to determine whether the child of two people related as second cousins or closer is at increased risk for common mood disorders or psychoses using data on prescription psychotropic medication and death records.
Researchers examined the degree of parental consanguinity via questionnaires completed during routine house calls after the birth of the child. For the main analysis, receipt of antidepressant or anxiolytic medications were used as an indicator of common mood disorders and receipt of antipsychotics as an indicator of psychoses.
In the cohort, 609 individuals were born to consanguineous parents. Overall, 35.8% of children born to first-cousin couples received antidepressant or anxiolytic medications compared with 26% of nonrelated offspring and 8.5% of first-cousin marriage offspring received antipsychotic medications compared with 2.7% of nonrelated children.
After adjusting for factors linked to poor mental health, analysis revealed that children born to first-cousin couples were more than three times as likely to receive antidepressant or anxiolytic medications (OR = 3.01; 95% CI, 1.24-7.31) and more than two times as likely to receive antipsychotic medication (OR = 2.13; 95% CI, 1.29-3.51) than children born to nonrelated parents. Although the link between being a child of second-cousin couples and receiving medications for mood disorders appeared high, it was not statistically significant.
“Sensitive advice about the risks associated with consanguineous unions should be provided to assist in reproductive decision-making,” Maguire told Healio Psychiatry. “This study calls on countries with large scale administrative datasets who have data on cousin marriage to replicate this study and asks for neonatal records worldwide to include information on degree of parental consanguinity.”
Objectively evaluating the medical, psychological and emotional risks of parental consanguinity for mental health research requires a sensitive approach due to the stigma linked to cousin marriage, Alison Shaw, MA, DPhil, senior research fellow in social anthropology at University of Oxford, wrote in a related editorial.
“Despite these caveats, the paper by Maguire [and colleagues] is important and should be a major stimulus to future efforts to understand the genetic contribution to common complex psychiatric conditions,” Shaw wrote. “Given the impetus toward whole-genome sequencing in many parts of the world, including among the rapidly modernizing Gulf states, we may have entire genomes at our disposal to guide genetic counseling for medical and psychiatric conditions.” – by Savannah Demko
Disclosures: The authors report no relevant financial disclosures. Shaw reports no relevant financial disclosures.