SEARCH · PubMed Health

Results for “Consanguinity”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources

PubMed1985

Frequency of consanguineous marriages among parents and grandparents of Down patients.

The existence of a rare autosomal gene which in the homozygous state would cause mitotic nondisjunction in the Down zygote has been hypothesized in the past by Alfi et al. (1980). This hypothesis can be supported or contradicted by the study of the frequency of consanguineous marriages among parents of affected children. Our study on 242 children affected with Down syndrome does not show any increase in the frequency of consanguineous marriages among their parents with respect to the general population, and therefore does not support the hypothesis of an autosomal gene controlling mitotic nondisjunction. Our data do not show any increase in the frequency of consanguineous marriages even among paternal and maternal grandparents of the affected children, thus not supporting the other possible explanation of an autosomal recessive condition in one of the patient's parents which would cause meiotic nondisjunction.

Adolescent↗

PubMed2002

Endogamy, consanguinity and community genetics.

The population of India is composed of many thousands of subpopulations, divided by geography, language, religion and caste or biraderi (patrilineage) boundaries, with endogamous marriage the norm. The net effect has been the creation of multiple genetic isolates with individual mutation profiles, but to date the clinical consequences of this highly complex differentiation have been largely ignored. In contrast, the topic of consanguinity continues to attract attention among medical and population geneticists, clinicians and social scientists. The significant progress made in India in improving childhood nutritional status and combating infectious disease means that genetic disorders have assumed ever-increasing importance. In populations where consanguineous marriage is widely practised, recessive genetic disorders will continue to gain greater prominence in the overall spectrum of ill health. At the same time this increase will in part be negated by urbanization and the move to smaller family sizes, which predictably will result in a decline in the prevalence of consanguineous unions. Developing an understanding of these changes will require a wide-ranging and multidisciplinary investigative approach for which community genetics is ideally suited.

Consanguinity↗

PubMed2003

Consanguinity as risk factor for cervical carcinoma.

Cervical carcinoma is caused by human papillomavirus (HPV). Among the risk factors for HPV infection are having multiple sex partners and sex partners who themselves had multiple sex partners. Women married to relatives are more likely to become infected with HPV and develop cervical carcinoma. Consanguineous spouses have a mild sexual aversion to each other that leads to sex avoidance and increases likelihood of satisfying sexual desire outside the marriage. Sexual aversion develops as a result of spouses growing together in early childhood, which triggers biological imprinting of Westermarck. Westermarck's effect prevents incest in nuclear family. In consanguineous family, it extends to spouses, producing mild sexual antipathy. Because of high prevalence of consanguinity worldwide, it is important to test this hypothesis.

Carcinoma↗

PubMed2001

Clinical findings, consanguinity, and pedigrees in children with anophthalmos in southern India.

This study aimed to describe clinical findings, pedigrees, and possible environmental risk factors in children with clinical anophthalmos and remnant microphthalmos in either eye in southern India. Twenty-four children (14 male, 10 female; mean age 10.3 years, age range 1.3 to 18 years,) were recruited from schools for the blind, hospitals, and community-based rehabilitation programmes in Andhra Pradesh, India, over 1 year. Family members were examined, and mothers interviewed. Fifteen children had anophthalmos and nine had remnant microphthalmos in one or both eyes. Twelve children had associated systemic findings, of which six were major and six were minor abnormalities. Information on consanguinity was available in 19 children, 12 of whom had consanguineous parents. Five children had a positive family history. Two mothers had a history of night blindness, and one had a history of pesticide exposure during pregnancy. High rates of consanguinity suggest a genetic recessive aetiology.

Adolescent↗

PubMed1994

Consanguineous marriage within social/occupational class boundaries in Pakistan.

Data on patterns of consanguineous marriage were collected from 5340 families resident in eight cities in the Pakistan province of Punjab. To assess whether social and/or occupational class was interacting with consanguinity, information also was obtained on the hereditary qaum to which each family belonged. In the present generation 46.5% of all marriages were contracted at the level of second cousin or closer, with an average coefficient of inbreeding (F) of 0.0286, and the results indicated that in each of the seventeen qaums there was strong preference for marriage to a close biological relative. However, significant differences existed in the distribution of consanguineous marriage by qaum membership, which could interfere with the interpretation of studies into the biological effects of inbreeding.

Analysis of Variance↗

PubMed2003

Effects of polygyny and consanguinity on high fertility in the rural Arab population in South Jordan.

Based on the authors' interview survey for 608 randomly selected women of the rural Arab population in the South Ghor district of Jordan, this paper examined the effects of polygyny and consanguinity on high fertility, which was recognized as natural fertility. The prevalence of polygynous and consanguineous marriages was 28.0% and 58.1%, respectively, largely reflecting the population's traditional marriage customs. The findings highlighted a significantly higher total marital fertility rate (TMFR) in the monogamous wives (10.5) than in the senior polygynous (8.1) and junior polygynous wives (8.6); the TMFR did not significantly differ among the wives of non-consanguineous, first-cousin and second-cousin marriages. The formation of polygynous marriage was decided by the husband, mostly as a result of his senior wife's infecundity or sub-fecundity, and the age of the husband at marriage to his junior polygynous wife was high in many cases, leading to a decline in this wife's fecundity.

Adolescent↗

PubMed2002

Science and society: genetic counselling and customary consanguineous marriage.

Consanguineous marriage is customary in many societies, but leads to an increased birth prevalence of infants with severe recessive disorders. It is therefore often proposed that consanguineous marriage should be discouraged on medical grounds. However, several expert groups have pointed out that this proposal is inconsistent with the ethical principles of genetic counselling, overlooks the social importance of consanguineous marriage and is ineffective. Instead, they suggest that the custom increases the possibilities for effective genetic counselling, and recommend a concerted effort to identify families at increased risk, and to provide them with risk information and carrier testing when feasible.

Bias↗

PubMed2002

The effect of reproductive compensation on recessive disorders within consanguineous human populations.

We investigate the effects of consanguinity and population substructure on genetic health using the UK Asian population as an example. We review and expand upon previous treatments dealing with the deleterious effects of consanguinity on recessive disorders and consider how other factors, such as population substructure, may be of equal importance. For illustration, we quantify the relative risks of recessive lethal disorders by presenting some simple calculations that demonstrate the effect 'reproductive compensation' has on the maintenance of recessive alleles. The results show how reproductive compensation can effectively counteract the purging of deleterious alleles within consanguineous populations. Whereas inbreeding does not elevate the equilibrium frequency of affected individuals, reproductive compensation does. We suggest this effect must be built into interpretations of the incidence of genetic disease within populations such as the UK Asians. Information of this nature will benefit health care workers who inform such communities.

Alleles↗

PubMed1998

The impact of consanguinity and inbreeding on perinatal mortality in Karachi, Pakistan.

Close consanguineous unions continue to be extremely common in much of West Asia, including Pakistan. However, the impact of inbreeding on offspring mortality, particularly perinatal mortality, remains poorly documented. This paper attempts to measure the mortality risks associated with consanguinity and inbreeding while controlling for the effects of other potential confounders. The study sample comprises a multi-ethnic population residing in selected squatter settlements of Karachi. The adjusted odds ratio for perinatal mortality in the offspring of women married to their first cousins was 2.0 [95% CI 1.5, 2.6]. When parental inbreeding was also taken into account, the adjusted odds ratio for perinatal mortality increased further. Analysis of a subsample of data limited to pregnancies to women aged 35 years or above (at the time of the survey) showed that, despite adjustment for important biological and socio-demographic factors, both consanguinity and inbreeding remained important predictors of perinatal mortality in the offspring. Implications of the present study for further research are highlighted.

Adolescent↗

PubMed2003

An analysis of consanguinity and social structure within the UK Asian population using microsatellite data.

We analysed microsatellite genotypes sampled from the Pakistani and Indian communities in Nottingham, UK, to investigate the genetic consequences of substructuring mediated by traditional marriage customs. The application of a recently developed likelihood approach identified significant levels of population substructure within the Pakistani community as a whole, as well as within the finer divisions of castes and biradheri. In addition, high levels of cryptic or unacknowledged consanguinity were detected within subgroups of this community, including biradheri. The Indian sample showed no significant evidence of either substructure or consanguinity. We demonstrate that estimates of disease gene frequencies can be inaccurate unless they are made jointly with estimates of population substructure and consanguinity ((theta congruent to FST) and C). The magnitude of these estimates also highlights the importance of accounting for the finer scale of social structuring when making decisions regarding the risk of recessive disorders in offspring.

Analysis of Variance↗

PubMedDate not supplied

Consanguinity, fecundity and post-natal mortality in Karnataka, South India.

The degree of consanguinity of the progeny, the number of live-borns and number of living children were determined in 3350 marriages in Bangalore, Karnataka. The coefficient of inbreeding (F) was 0-02308, higher than in comparable, urban populations in other South Indian states. No significant differences were found between the consanguineous and nonconsanguineous groups in numbers of live-born or living children nor was there any consanguinity-related trend with respect to these parameters.

Birth Rate↗

PubMedDate not supplied

Consanguineous marriages in Denizli, Turkey.

For the study 1000 families were interviewed during 1996 in the city of Denizli, which is situated in Western Anatolia and has a population of 79211 families. The overall rate of consanguinity was 11.7%, with a mean inbreeding coefficient of 0.00873. The principal type of consanguineous marriage recorded was between first cousins, which accounted for 49.6% of all unions. For both sexes, a significant negative association was observed between consanguinity and mean age at marriage and level of education.

Adolescent↗

PubMed2001

Low proportion of familial dilated cardiomyopathy in an arab population with a high prevalence of consanguineous marriages.

UNLABELLED: In this study, 770/890 (87%) first-degree relatives from 108 families of hospitalized patients with idiopathic dilated cardiomyopathy (IDC) were screened using clinical examination, electrocardiography and echocardiography. Thirty percent of the patients were born to consanguineous parents. Familial dilated cardiomyopathy (FDC) was found in 7 (6.5%) families, which is lower than the earlier published figures of 20-25%. Patients with IDC were younger at presentation (p = 0.002) and were more often associated with parental consanguinity (p = 0.04). but the survival rates of familial patients did not differ significantly. CONCLUSION: Despite the high prevalence of consanguinity, there was a low proportion of FDC in the study population. With the prospects of treatment of asymptomatic IDC to slow the progression of the disease, all family members of newly identified IDC patients should receive screening and counselling, with appropriate therapy where indicated.

Adolescent↗

PubMedDate not supplied

Selection intensities and consanguineity in the Yadava and Vadabalija of Visakhapatnam, Andhra Pradesh, India.

The opportunity for intensity of selection is studied in two backward caste groups with different occupations, namely Yadava (pastoral) and Vadabalija (fishing) of Bheemunipatnam Taluk of Visakhapatnam District, Andhra Pradesh. The amount of selection intensity is found to be higher in Vadabalija (0.8583) than Yadava (0.5827). The contribution of mortality to the total index of selection is greater in Vadabalija (0.6095) than in Yadava (0.3326). When consanguineity is considered, the fertility components of selection intensity (0.1885) are lower in the consanguineous group of Yadava than in the nonconsanguineous group (0.2845), whereas in Vadabalija they are higher in the consanguineous group (0.5261) than in the nonconsanguineous group (0.2223).

Consanguinity↗

PubMedDate not supplied

Consanguinity and its trend in a Mendelian population of Andhra Pradesh, India.

Consanguineous marriages have decreased significantly (p < 0.01) among the Kamma of Andhra Pradesh over the past forty years. The decline in uncle-niece marriages has contributed heavily to the decline in consanguinity, which may be due to shifting from agriculture to other occupations like government service and the rapid growth of industrialization. More recently, the tendency toward a lower consanguinity rate has been strengthened by reduction in number of children per marriage which reduces the number of eligible cousins. Marriages beyond first cousin have remained more or less constant.

Consanguinity↗

PubMed2006

Quantification of homozygosity in consanguineous individuals with autosomal recessive disease.

Individuals born of consanguineous union have segments of their genomes that are homozygous as a result of inheriting identical ancestral genomic segments through both parents. One consequence of this is an increased incidence of recessive disease within these sibships. Theoretical calculations predict that 6% (1/16) of the genome of a child of first cousins will be homozygous and that the average homozygous segment will be 20 cM in size. We assessed whether these predictions held true in populations that have preferred consanguineous marriage for many generations. We found that in individuals with a recessive disease whose parents were first cousins, on average, 11% of their genomes were homozygous (n = 38; range 5%-20%), with each individual bearing 20 homozygous segments exceeding 3 cM (n = 38; range of number of homozygous segments 7-32), and that the size of the homozygous segment associated with recessive disease was 26 cM (n = 100; range 5-70 cM). These data imply that prolonged parental inbreeding has led to a background level of homozygosity increased approximately 5% over and above that predicted by simple models of consanguinity. This has important clinical and research implications.

Chromosome Disorders↗

PubMed1989

Effects of consanguineous matings on anthropometric measurements of Saudi newborn infants.

The effects of parental consanguinity on gestation age and anthropometric measurements of 4497 Saudi newborn infants have been evaluated. The incidence of consanguineous matings was high, about 54.3%. For purposes of statistical analysis, marriages were classified into three groups based on degree of consanguinity. The results of the study reveal no significant effects of inbreeding on gestational age. Neither were any significant differences observed by type of marriage in weight, height or head, chest and mid-arm circumference at birth. It is suggested that inbreeding does not lead to significant effects of fetal growth among Saudi newborns.

Anthropometry↗

PubMed1994

Reflections on the consanguinity and birth outcome debate.

The high rate of consanguineous marriages has been implicated as an important factor in the high rates of perinatal mortality and congenital malformations among the UK Pakistani population. This paper critically considers the debate on consanguinity and birth outcome. A critical review of epidemiological literature is placed in the context of wider, but centrally important, debates on social class and ethnic categorizations, notions of culture and literature on racism. The epidemiological literature is inconsistent in its findings, and is often based on data and arguments of dubious validity. Equally, notions of social class, ethnicity and culture used in such studies lack sophistication and require reconsideration. Health policy options based on promoting cultural change in marriage patterns, conveniently but unjustifiably, shift the blame of poor birth outcome onto the Pakistani community and are doomed to failure. The consanguinity hypothesis is over-simplistic to explain the higher rates of perinatal mortality and congenital malformations among the Pakistani population. Its popularity rests less on its scientific merit and more on its convenience in shifting the blame onto supposedly deviant cultures and marriage patterns and its fit with racist ideas of alienness and deviance.

Adult↗