Consanguineous Marriage and the Psychopathology of Progeny

Abstract

A child of consanguineous parents is at increased risk of common mood disorders and psychoses.

Consanguineous Marriage and the Psychopathology of the Progeny of First-Cousin Couples

“…3,4 The definition of cousin is not universal: it may denote a social category rather than a person in a particular genealogical position, and, in terms of shared blood, a father's-side cousin may be viewed as closer than a cousin on the mother's side of the family. 8 This calls for caution in using risk data from the study from Northern Ireland by Maguire et al 5 for counseling couples elsewhere in the world.…”

“…Collecting nationwide data on parental consanguinity for health research will require sensitivity to the stigma currently associated with cousin marriage on grounds of genetic risk, and this is true beyond Western Europe. 8 Despite these caveats, the paper by Maguire et al 5 is important and should be a major stimulus to future efforts to understand the genetic contribution to common complex psychiatric conditions. Given the impetus toward wholegenome sequencing in many parts of the world, including among the rapidly modernizing Gulf states, 8,11 we may have entire genomes at our disposal to guide genetic counseling for medical and psychiatric conditions.…”

“…What has not until now been demonstrated is that parental consanguinity also elevates the risk for serious common psychiatric disorders. In their population-wide data-linkage study from Northern Ireland, Maguire et al used pharmacy prescriptions for antipsychotic medications and antidepressant drugs as proxies for psychoses and severe depression, respectively, to investigate this risk. Adult offspring of first-cousin parents were more than 3 times more likely than individuals with nonconsanguineous parents to be receiving mood-disorder medication and more than twice as likely to be receiving antipsychotic medication, after controlling for other factors known to be associated with these conditions.…”

“…Risk information is also only as good as the data on which it is based. One of the reasons why the elevated medical risks associated with consanguineous marriage are (as Maguire et al note) hotly debated is that establishing accurate levels of consanguinity is difficult. Particular recessive mutations may be more prevalent within endogamous subpopulations even where marriages are not consanguineous, and first cousins with a family history of consanguineous marriage across generations may have a higher risk than first cousins without any additional consanguinity .…”

“…Despite these caveats, the paper by Maguire et al is important and should be a major stimulus to future efforts to understand the genetic contribution to common complex psychiatric conditions. 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.…”