A review of consanguinity in Ireland--estimation of frequency and approaches to mitigate risks.

INTRODUCTION: Over half of marriages are consanguineous in some countries, and about 10 % of children worldwide have consanguineous parents. Perceived benefits of consanguineous marriage (CM) include preservation of tradition, stronger family ties, financial advantages, and bride protection. Potential harms include autosomal recessive disorders, complex congenital malformations, stillbirths, postnatal mortality. There have been no population-based data published on frequency of CM in Ireland since 1970.
METHODS: International prevalence figures and published estimates of CM were applied to 2011 Irish Census data to calculate the frequency of CM in at-risk groups. Searches of the published and grey literature were conducted to review evidence-based approaches to mitigate risks of CM and apply findings to the Irish context.
RESULTS: The estimated number of consanguineous couples has grown in subpopulations in Ireland in the past decade, particularly among Pakistanis (>967 couples), Nigerians (418-794 couples) and Indians (54-2099 couples). There are up to 3000 consanguineous couples in the Traveller community. Evidence for approaches to mitigate associated risks supports a three-stranded approach: family-centred genetics services, training and education of healthcare professionals (HCPs), community education programmes. DISCUSSION: Consanguineous couples desire accurate information for reproductive decisions, but may avoid hospital-based services due to language barriers, poor understanding, stigma. Uptake of genetic counselling and carrier testing is higher if a family-centred approach is provided, ideally through home visits in the couple's preferred language. Targeted education programmes enhance community awareness and have led to declines in CM elsewhere. Education of HCPs is necessary to clarify referral pathways, as many have exaggerated impressions of the genetic risks.