From the Journals

Consanguineous parentage raises risk of mood disorders, psychoses in offspring


Key clinical point: Children of consanguineous parents are at significantly greater risk of mood disorders.

Major finding: Children of first-cousin parents have a threefold greater risk of mood disorders.

Study details: A retrospective populationwide cohort study involving 363,960 individuals.

Disclosures: The study was funded by the Centre of Excellence for Public Health Northern Ireland, with additional assistance from the Honest Broker Service. No conflicts of interest were declared.

Source: Maguire A et al. JAMA Psychiatry. doi: 10.1001/jamapsychiatry.2018.0133.

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Findings should stimulate research

While Charles Darwin – himself the product of a consanguineous marriage – found no evidence of a higher prevalence of consanguineous parentage among the inmates of asylums in England, there is known to be a higher risk of recessively inherited single-gene disorders among the offspring of consanguineous couples. However, until now, it was not known whether this also included an elevated risk of psychiatric disorders.

The findings of this study should stimulate further research efforts toward a greater understanding of the genetic contribution to common complex psychiatric conditions. The increase in whole-genome sequencing could provide entire genomes to help guide genetic counseling, not only for medical but also psychiatric conditions.

The study also should raise awareness about the difficulties and challenges associated with determining consanguinity, amid the potential stigma associated with cousin marriage.

Alison Shaw, DPhil, is affiliated with the department of social anthropology at the University of Oxford (England). These comments are taken from an accompanying editorial (JAMA Psychiatry 2018. Apr 4. doi: 10.1001/jamapsychiatry.2018.0513). No conflicts of interest were declared.



Children of consanguineous parents are three times more likely to be prescribed medications for common mood disorders than the children of nonrelated parents, according to a study published April 4.

In JAMA Psychiatry, researchers reported the results of a retrospective populationwide cohort study involving 363,960 individuals born in Northern Ireland between 1971 and 1986; 609 (0.2%) of whom were born to parents who were either first or second cousins.

The analysis showed a clear relationship between the degree of consanguinity and the likelihood of being prescribed psychotropic medications. After adjusting for known mental health risk factors, including birth weight, children of parents who were first cousins had threefold higher odds of being prescribed antidepressant or anxiolytic medicines (odds ratio, 3.01; 95% confidence interval, 1.24-7.31) and a twofold higher odds of receiving antipsychotics (OR, 2.13; 95% CI, 1.29-3.51), compared with the children of nonconsanguineous parents.

“The results illustrate a clear increasing, stepwise association between level of consanguinity and mental ill health, suggesting a quasi–dose-response association, supporting a causal association between consanguineous parents and mental health of progeny,” wrote Aideen Maguire, PhD, and colleagues from Queen’s University Belfast (Northern Ireland).

Overall, more than one-third (35.8%) of children born to first-cousin consanguineous unions were prescribed antidepressant or anxiolytic medication, and 8.5% received antipsychotic medications, compared with one-quarter (26%) and 2.7% of nonrelated offspring.

Children of parents who were second cousins had an elevated but not statistically significant risk of receiving psychotropic medications (OR, 1.31; 95% CI, 0.63-2.71). None of these associations were affected by whether the births were singleton or multiple births.


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