Consanguinity and child health

doi:10.1016/j.paed.2008.02.008

Paediatrics and Child Health

Volume 18, Issue 5, May 2008, Pages 244-249

https://doi.org/10.1016/j.paed.2008.02.008 Get rights and content

Abstract

Marriage between close biological kin is widely regarded as genetically disadvantageous in contemporary Western societies, but consanguineous unions remain preferential in North Africa, the Middle East and large parts of Asia, with marriage between first cousins particularly popular. Many major populations also are subdivided into endogamous communities that have distinctive breeding pools. It is in these populations that intra-community marriage principally governs the spectrum of observed diseases. Because of population subdivision, and because the poorest sections of all populations are most disadvantaged in terms of health and health care provision, there are difficulties in assessing the effects of consanguinity alone on morbidity and mortality. A positive association has been repeatedly shown between consanguinity and childhood morbidity due to the expression of detrimental recessive genes. Examples include deafness, retinal dystrophies, intellectual and developmental disability and complex congenital heart disease. Increased incidences of thalassaemia and other haematological disorders also are reported in many populations. Given the recent patterns of immigration, many Western countries have continued exposure to consanguineous unions, which necessitates the provision of more focused resources to improve the delivery of prospective genetic counselling, prenatal testing, treatment and community care. In communities where consanguineous marriage forms an integral and valued part of the cultural tradition, external attempts to discourage close-kin unions at the population level are inappropriate and unlikely to be successful.

Section snippets

Cosanguineous union: basic concepts

Definitions: the term ‘consanguineous’ is from the Latin consanguineus, meaning ‘of the same blood’.

In human genetics, a couple are said to be consanguineous if they share one or more common ancestors. Because most pairs of individuals living in the same location have a common ancestor somewhere in their family tree, for practical purposes the search for a shared ancestor usually does not extend back more than three or four generations.

In medical genetics, consanguineous marriage is commonly

Global prevalence of consanguinity

Data on the global distribution of consanguineous marriages are summarized in Figure 1.

Differences between regions: the lowest rates of consanguinity are found in Western Europe, North America and Oceania, where less than 1% of marriages are consanguineous (i.e. unions between couples related as second cousins or closer (F ≥ 0.0156)).

In some parts of Southern Europe, South America and Japan, ∼1–5% of marriages are consanguineous, depending on local geography and social customs.

The highest rates

Civil legislation on consanguineous marriage

Consanguineous unions are largely avoided in Western Europe and Oceania, but first-cousin marriage is permissible under civil law in virtually all countries; half-sibs (F = 0.125) also have been permitted to marry under specific circumstances in Sweden since 1987.

The situation is quite different in the USA where, until 1861, first-cousin marriage was legal. Legislation to ban different types of consanguineous marriage was gradually introduced, the most recent example being a ban on first-cousin

Social and economic factors associated with consanguinity

The preference for consanguineous marriage is primarily social, but economic considerations are an important part of partner choice (Table 2).

Premarital arrangements are simplified in a consanguineous union, and the relationship of a couple and their in-laws is expected to be more congenial and thus beneficial to female autonomy in patriarchal societies. It is also believed that family ties will be strengthened, and health or financial uncertainties with a partner from another family or

Effects of inbreeding on society

The prevailing suspicion about consanguineous unions in Western societies centres on the belief that the offspring of a close kin marriage will be physically and/or mentally disadvantaged. This perception has been used by many in the medical community and in public life to suggest that consanguinity should be discouraged on the grounds of medical expense and/or morality.

Congenital defects with complex causes appear to be more common in consanguineous families and, in gauging the influence of

Summary

The future prevalence and status of consanguineous marriage is a matter of conjecture. It could be argued that the ongoing widespread popularity of consanguinity makes a rapid decline in its prevalence improbable. In many developing countries, strenuous official efforts are being made to lessen the appeal of close-kin unions, although with no apparent appreciation or acknowledgement of the balancing social and economic benefits.

The situation for migrant communities in Western societies is

Acknowledgement

AHB is funded by National Science Foundation Grant 0527751.

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Cited by (32)

Linkages between consanguineous marriages and childhood stunting: Evidence from a cross-sectional study in India
2021, Children and Youth Services Review
Citation Excerpt :
Consanguinity also prevails in some societies: between 20 and 45 percent of marriages in the Hindu-majority states of South India are contracted between close relatives, and those mostly occur between uncle and niece (Bittles, 1994; Sharma, Kalam, Ghosh, & Roy, 2020). Several studies have documented that inbreeding increases the risk of child mortality due to the expression of detrimental recessive genes (Dorsten, Hotchkiss, & King, 1999; Saggar & Bittles, 2008), but the linkages between consanguinity and a broader array of child development outcomes are yet to be studied in-depth. Such research on consanguinity tends to suffer from limitations owing to the limited sample sizes or fewer outcomes of interest, or both.
The present research aims to decode the ties between marriages within blood relation (consanguineous marriages) and childhood stunting in India using the latest round of National Family Health Survey, conducted during 2015–16. The present study utilizes data on 192,357 ever-married women age 15–49 years and 14,707 children under age five years from National Family Health Survey, India, 2015–16. To draw inferences from the data, bivariate and multivariable logistic regression has been utilized. A Propensity Score Matching technique has been used to understand the causal linkages between consanguineous marriages and childhood stunting. The prevalence of childhood stunting was higher among male child (40%) compared to the female child (38%) among women who have married their blood relatives. The findings hint’s a significant association between consanguineous marriages and childhood stunting. Multivariable regression and propensity score matching results also show that childhood stunting was significantly higher in consanguineous marriages compared to non-consanguineous marriages in the country. Thus, to reduce childhood stunting among children born to women married to their blood relatives, measures like premarital and pre-conception counselling need to be taken for the individuals opting for consanguineous marriages.
Classification of various types of disability and determining their predictive causes in western Iran
2020, Clinical Epidemiology and Global Health
Citation Excerpt :
However, there can be a wide range of causes for visual and auditory disability. For instance, the results of a study on the relationship between cousin marriages and children's health in African and Asian countries show that cousin marriage is related to disorders such as deafness due to its effects through latent genes.29 Moreover, the results of another study show that 89% of the cases, blindness is caused by genetic factors and only 11% of the blindness cases are caused by external factors.30
The current study aims to clustering different types of disability in Kermanshah Province and determine its predictive causes.
The statistical population of this cross-sectional study includes all the households living in rural and urban areas of Kermanshah Province in western Iran. Using multi-stage cluster sampling, 10150 households were selected from July to December of 2017 based on the population share of each city district. The required data were obtained using a 13-item questionnaire developed by the research team. The obtained data were analyzed using two-step cluster analysis, chi-square test, and multinomial logistic regression analysis.
This model suggested five clusters including (i) geographically scattered subjects with mental abnormalities, (ii) geographically scattered subjects with physical motor abnormalities, (iii) non-eastern subjects with multiple abnormalities, (iv) non-northern subjects with multiple abnormalities, and (v) geographically scattered subjects with visual-auditory abnormalities. Multinomial logistic regression emphasized the significance of some causes of disability, particularly head trauma and trauma caused by car accidents (P < 0.05). There was a significant difference among the clusters with regard to socio-demographic variables (P < 0.05).
The eastern areas of Kermanshah province are facing a larger number of mental disorders caused by mother's disease during pregnancy and cousin marriages. Other major causes of disability include head trauma and trauma caused by car accidents. In western areas, physical-motor disability is more frequent, and in central areas, visual-auditory abnormalities are more prevalent.
A novel NKX3-2 mutation associated with perinatal lethal phenotype of spondylo-megaepiphyseal-metaphyseal dysplasia in a neonate
2019, European Journal of Medical Genetics
Citation Excerpt :
Last but not least, rare autosomal recessive entities including SMMD should be kept in mind in patients with parental consanguinity. Turkey where consanguineous marriages are commonly encountered (Hacettepe University Institute of Population Studies, 2014) is at the lower end of the highest consanguinity prevelance band (>20–50%) along with several nations in North Africa, the Middle East, Pakistan, and India (Saggar and Bittles, 2008). The higher rate of consanguineous marriages in Turkey likely increases the frequency of rare autosomal recessive entities (Tuncbilek, 2001) including various genetic skeletal disorders (Kurt-Sukur et al., 2015).
Spondylo-megaepiphyseal-metaphyseal dysplasia (SMMD) is an autosomal recessive skeletal dysplasia, characterized by disproportionate short stature with a short and stiff neck and trunk. SMMD is caused by inactivating mutations in NKX3-2, which encodes a homeobox-containing protein. Because of the rarity of the disorder, the diagnostic feature has not been fully established yet. We describe an affected newborn with dysmorphic facial features and severe short trunk. The patient required immediate intubation at the delivery room and duodenal atresia was detected during his course in neonatal intensive care unit. Skeletal survey revealed total absence of the ossification of the vertebral bodies, pubis, and ischia. Mainly the femora was short and broad with mild flaring of the metaphyses. The downward sloping or tented appearance of the ribs was distinctive. A diagnosis of SMMD was made on clinical and radiological grounds. Molecular analysis revealed homozygosity for a novel mutation, c.507-508delCA (p.Gly171Cysfs*55) in exon 2 of NKX3-2. The patient was operated on postnatal day 7 for duodenal atresia. In the post-operative period he developed sepsis and respiratory failure and he died on postnatal day 14. Although no neuroradiologic imaging could be performed, the findings of clubfoot, neuromuscular respiratory insufficiency requiring invasive mechanical ventilation and downward sloping or tented appearance of the ribs were suggestive of very early cervical cord compression leading to perinatal mortality. To our knowledge this patient yet represents one of the most severe postnatal phenotypes of SMMD.
Consanguinity and rare neurological disease. A five year experience from the Korle Bu Teaching Hospital, Accra, Ghana
2016, eNeurologicalSci
Marriage between close biological kin is not regarded as advantageous in the western world but in other parts of the world, consanguineous unions persist. Consanguineous marriage increases the birth prevalence of individuals with recessive disorders. In Accra, Ghana, consanguinity is beginning to emerge as a significant cause of rare neurological disease at the central referral hospital at Korle Bu in Ghana.
Documentation of rare neurological and genetic diseases over a five year period resulting from consanguinity (2010–2015) presenting to the Department of Child Health, Korle Bu Teaching Hospital, Accra.
One of the three siblings with zeroderma pigmentosum was identified as the rare De Sanctis Cacchione syndrome which has not been previously reported from West Africa. Five cases of spinal muscular atrophy including three consecutive siblings with the disease, MCAD deficiency (1), inborn errors of metabolism (1), ceroid lipoid fuscinosis (6), a case of Meckel Gruber syndrome.
Rare neurological disease occurs in West African communities as a result of consanguinity.
Development of a Sustainable Disabled Population in Countries of the Cooperation Council for the Arab States of the Gulf
2014, Global Sustainable Communities Handbook: Green Design Technologies and Economics
This chapter presents results of a grounded theory literature search on sustainability of the disabled population in countries of the Cooperation Council for the Arab States of the Gulf (GCC), which are composed of the countries surrounding the southern coast of the Persian Gulf and Oman. Research focused on the adaptability of the GCC’s Arabic culture to accommodate a growing number of disabled people in its population, the potential areas of an increase or a decrease in its disabled population, and the advantages and potential problems in the societies of the GCC’s constituent countries.
Consanguinity profile in the Gaza Strip of Palestine: Large-scale community-based study
2014, European Journal of Medical Genetics
Citation Excerpt :
Unfortunately, this perspective is not reflected in the rest of the world, including the Middle East, and such marriages are still a frequent occurrence where various religious, social and economic rewards to the arrangement of first- and second-cousin marriages are commonly acknowledged. The global occurrence of consanguineous marriages reflected a heterogenous distribution, with the lowest prevalence (<1.0%) reported in Western Europe, North America and Oceania, while the highest (50% or more) was seen in North Africa, the Middle East and much of Central and South Asia [Saggar and Bittles, 2008]. In the Arab countries, where the people largely share common social and cultural traditions and religious perspectives, the consanguinity profile has revealed some differences between countries.
Consanguineous marriages which have been practiced throughout history continue to be practiced within different ethnic, religious and social groups to varying degrees with highest prevalences in North Africa, Middle East and central and south Asia. In the Gaza Strip of Palestine, little is known about the consanguinity profile, so the present large-scale study aims to explore the consanguinity profile of two generations using data from the β-thalassemia premarital screening program. Sociodemographic data analysis included 156,635 (141,200 males and 15,435 females) persons and their parents, representing 141,200 couples who were referred to the Thalassemia and Hemophilia Center for premarital testing. In addition, the consanguinity characteristics of parents of 217 transfusion-dependent β-thalassemic non-sibling patients were analyzed. Results revealed a significant decrease in the overall prevalence of consanguineous (first- and second-cousin) marriages between the previous (fathers') generation (45.2%) and the current (groom/bride) generation (39.9%). Among the five governorates of the Gaza Strip, records of Gaza Governorate revealed the lowest occurrence (36.9% current generation and 42.1% previous generation) of consanguineous marriages, as compared to all others. Consanguineous marriages are significantly higher in semi-urban areas (41.6%) than in urban areas (39.1%) in the current generation (previous generation, 46.4% vs 44.7%, respectively). Compound consanguinity (two generation) and a single level of consanguinity were seen in 20.7% and 43.7%, respectively, of the cases. The average age of those with first-cousin marriages is significantly lower (22.4 ± 4.4 years) than those with second-cousin marriages (24.3 ± 6.1 years) and the non-consanguineous (26.5 ± 8.2 years). The rate of consanguineous marriages among never married people (42.2%) is significantly much higher than the rate of people with multiple marriages (18.1%). About 74.7% of the non-sibling thalassemic patients of the Gaza Strip are associated with consanguineous parents, of them 54.4% first-cousins and 20.3% second-cousins.
In conclusion, although there is a decline in the consanguinity profile in the present compared to previous generation, consanguineous marriages are still a common practice in the Gaza Strip, which rationalizes the necessity for more awareness and counseling efforts about the potential health-related risks of consanguinity on individual lives and the population overall.

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Occasional reviewConsanguinity and child health

Abstract

Section snippets

Cosanguineous union: basic concepts

Global prevalence of consanguinity

Civil legislation on consanguineous marriage

Social and economic factors associated with consanguinity

Effects of inbreeding on society

Summary

Acknowledgement

Hum Immunol

Endogamy, consanguinity and community genetics

J Genet

The bases of western attitudes to consanguineous marriage

Dev Med Child Neurol

The fate of 12 recessive mutations in a single village

Ann Hum Genet

Intellectual disability and cerebral palsy in a UK community

Commun Genet

The role and significance of consanguinity as a demographic variable

Pop Dev Rev

Endogamy in the Arab world

Community perceptions of reasons for preference for consanguineous marriages in Pakistan

J Biosoc Sci

Consanguinity and its relevance to clinical genetics

Clin Genet

Prevalence and sociodemographic correlates of consanguineous marriages in Turkey

J Biosoc Sci

Does inbreeding lead to decreased human fertility?

Ann Hum Biol

Occasional review
Consanguinity and child health