Pattern Of Consanguinity Research Articles

The Birth Prevalence of Congenital Hyperinsulinism: A Narrative Review of the Epidemiology of a Rare Disease.

Congenital hyperinsulinism (HI) is a rare pediatric disease and the most common cause of severe, persistent hypoglycemia in childhood. It is characterized by the dysregulation of insulin secretion from the pancreas and can lead to irreversible brain damage with lifelong neurodisability. The global birth prevalence of HI is currently unknown. An evidence-based estimate of HI birth prevalence is essential to improve diagnosis and patient management, to drive clinical research and the development of new treatments, and to inform public policy. In order to estimate the birth prevalence of persistent HI, a targeted literature review of studies that report HI epidemiological data was undertaken, and the strengths and limitations of each study were analyzed. Overall, eight global studies were identified that reported independently determined HI epidemiological data. The best estimate for the birth prevalence of persistent HI in European-ancestry populations is 3.5 per 100,000 births. Local consanguinity patterns appear to have a considerable impact on the birth prevalence of persistent HI in each country, precluding the application of this figure to all global populations. More epidemiological studies with robust methodology are needed to enable a reliable approximation of the incidence and prevalence of HI in global populations.

Changes in prevalence and patterns of consanguinity in Bradford, UK – evidence from two cohort studies

Background Research undertaken using the Born in Bradford cohort study identified consanguinity as a major risk factor for congenital anomalies and also reported longer term adverse health outcomes associated with consanguinity. Methods We report the prevalence of consanguinity from two cohort studies in the same geographical area with a nine year gap: Born in Bradford (BiB) and Born in Bradford’s Better Start (BiBBS). We examine and compare rates of consanguinity and the characteristics of the consanguineous in each study population to examine if and how these have changed in the years between the recruitment periods of 2007–2010 (BiB) and 2016–2019 (BiBBS). Results There had been a substantial decrease in consanguineous unions in women of Pakistani heritage, the proportion of women who were first cousins with the father of their baby fell from 39.3% to 27.0%, and those who were other blood relations fell from 23.1% to 19.3%. Only 37.6% of Pakistani heritage women were unrelated to the father of their baby in BiB, but 53.7% were unrelated in BiBBS. All but one White British respondent was unrelated to their baby’s father in both cohorts, and around 90% of the ‘Other ethnicities’ group (i.e., not White British or Pakistani heritage) were unrelated to the baby’s father in both cohorts. The reduction was most marked in women of Pakistani heritage who were born in the UK, in those educated to A level or higher and in women under age 25. Conclusions An appreciation of changing rates of consanguinity and linked health needs will be valuable to those who commission and provide antenatal, paediatric and genetic services in Bradford and in other areas where consanguinity is likely to be a major risk factor. Falling rates in this city may reflect wider changes in partner choices in similar populations.

Thirty Years of Consanguineous Marriages in Pakistan

Almost half of all marriages in Pakistan are consanguineous. Despite its high prevalence, little is known about the change over time in consanguineous unions in Pakistan. Examining the patterns of the cousin marriages is particularly important given the substantial improvement in women’s education which is often associated with the decline in consanguineous unions across the world. Our analysis, based on four waves of nationally representative Pakistan Demographic and Health Surveys - PDHS (1990-91, 2006-07, 2012-13, and 2017-18), shows that the prevalence of consanguineous unions remains stable over time. Further, women’s education is negatively associated with cousin marriages. Hypergamous (husband is more educated than her wife) unions are more prevalent, but a consistent rise in educational hypogamy (wife is more educated than her husband) is observed during this time. The results show that consanguineous marriages are more likely to be hypogamous than non-consanguineous marriages. Moreover, contraceptive use is lower among women in consanguineous unions. An inverse relationship has been found between the mean fertility and cousin marriages. Women in consanguineous marriages are likely to have fewer children than women in non-consanguineous marriages. Overall, the results show that consanguinity patterns are stable, and there is no evidence that the societal changes such as improvement in women’s education and urbanization over time have led to a decline in cousin marriages in Pakistan.

Thirty Years of Consanguineous Marriages in Pakistan

Almost half of all marriages in Pakistan are consanguineous. Despite its high prevalence, little is known about the change over time in consanguineous unions in Pakistan. Examining the patterns of the cousin marriages is particularly important given the substantial improvement in women’s education which is often associated with the decline in consanguineous unions across the world. Our analysis, based on four waves of nationally representative Pakistan Demographic and Health Surveys - PDHS (1990-91, 2006-07, 2012-13, and 2017-18), shows that the prevalence of consanguineous unions remains stable over time. Further, women’s education is negatively associated with cousin marriages. Hypergamous (husband is more educated than her wife) unions are more prevalent, but a consistent rise in educational hypogamy (wife is more educated than her husband) is observed during this time. The results show that consanguineous marriages are more likely to be hypogamous than non-consanguineous marriages. Moreover, contraceptive use is lower among women in consanguineous unions. An inverse relationship has been found between the mean fertility and cousin marriages. Women in consanguineous marriages are likely to have fewer children than women in non-consanguineous marriages. Overall, the results show that consanguinity patterns are stable, and there is no evidence that the societal changes such as improvement in women’s education and urbanization over time have led to a decline in cousin marriages in Pakistan.

Prevalence of Retinitis Pigmentosa in a Tertiary Eye Hospital of Nepal.

Retinitis Pigmentosa (RP) is a group of diffuse retinal degenerative diseases predominantly affecting the rod and cone photoreceptors. The prevalence of retinitis pigmentosa seen in literature is approximately 1:4000. Retinitis Pigmentosa is one of the the most common causes of blindness in the age group of 20 to 40 years. The objective of this study was to determine the profile of retinitis pigmentosa in Terai and Nepal-India border region considering patients seeking care at a Tertiary level Eye Hospital in the terai region (southern part) of Nepal. A hospital-based, retrospective study was carried out at R. M. Kedia Eye Hospital. A total of 385 (83 males and 107 females from Nepal and 109 males and 86 females from India) diagnosed patients of Retinitis Pigmentosa were included in the study. Data was collected over a period of eleven years from 2008-2018. Out of 385 diagnosed Retinitis Pigmentosa patients, 192 (49.87%) were male and 193 (50.13%) were female with slightly female predominance. The prevalence of RP seen in our study was 0.03%. About 51% of the patients visited here were from India and nearby border areas/ villages which cover most of the rural areas of India. In this study it was found that 49.34% of the RP cases were from Nepal, of which 43.63% of cases were from Hindu community and 5.71% from Muslim community and about 50.66% cases of RP were from India, of which 37.67% from Hindu and 12.98% from Muslim community. The peak age of presentation of RP was at 30-39 years (29.09%), followed by 20-29 years (26.75%). The common marriage pattern of consanguinity was found in Muslim community in between the first cousins. In this study the hospital record did not show any evaluation for the syndromic disease in the hospital record, though RP is usually non syndromic and there are literatures where many syndromic forms have been identified. The prevalence of RP seen in the study was 0.03% (A total of 1101299 sample population of which 385 patients had RP). Since RP is an inherited disease and is one of the non-treatable causes of blindness which runs in the families, a role of counseling to reduce consanguineous marriages should be brought forward to reduce the disease process.

Fine-scale population structure and demographic history of British Pakistanis

Previous genetic and public health research in the Pakistani population has focused on the role of consanguinity in increasing recessive disease risk, but little is known about its recent population history or the effects of endogamy. Here, we investigate fine-scale population structure, history and consanguinity patterns using genotype chip data from 2,200 British Pakistanis. We reveal strong recent population structure driven by the biraderi social stratification system. We find that all subgroups have had low recent effective population sizes (Ne), with some showing a decrease 15‒20 generations ago that has resulted in extensive identity-by-descent sharing and homozygosity, increasing the risk of recessive disorders. Our results from two orthogonal methods (one using machine learning and the other coalescent-based) suggest that the detailed reporting of parental relatedness for mothers in the cohort under-represents the true levels of consanguinity. These results demonstrate the impact of cultural practices on population structure and genomic diversity in Pakistanis, and have important implications for medical genetic studies.

Fine-scale population structure in five rural populations from the Spanish Eastern Pyrenees using high-coverage whole-genome sequence data

The area of the Spanish Pyrenees is particularly interesting for studying the demographic dynamics of European rural areas given its orography, the main traditional rural condition of its population and the reported higher patterns of consanguinity of the region. Previous genetic studies suggest a gradient of genetic continuity of the area in the West to East axis. However, it has been shown that micro-population substructure can be detected when considering high-quality NGS data and using spatial explicit methods. In this work, we have analyzed the genome of 30 individuals sequenced at 40× from five different valleys in the Spanish Eastern Pyrenees (SEP) separated by less than 140 km along a west to east axis. Using haplotype-based methods and spatial analyses, we have been able to detect micro-population substructure within SEP not seen in previous studies. Linkage disequilibrium and autozygosity analyses suggest that the SEP populations show diverse demographic histories. In agreement with these results, demographic modeling by means of ABC-DL identify heterogeneity in their effective population sizes despite of their close geographic proximity, and suggests that the population substructure within SEP could have appeared around 2500 years ago. Overall, these results suggest that each rural population of the Pyrenees could represent a unique entity.

Is Marriage a Risk Factor for Allergic Rhinitis?

Objective: Our study aimed to determine the effect of marriage and sexual activity as risk factors for allergic rhinitis and to figure out degree of impact of consanguinity in the Saudi population on allergic rhinitis. Study design: A cross sectional study. Methods: The study was conducted at the outpatient ENT clinic of King Faisal University polyclinic centre at the period from October 2015 to February 2016. A random of 60 patients of age group 20-55 years old including both sex. The inclusive criteria were patients experienced symptoms related to out- door, indoor allergic rhinitis in the past 12 months. All of them were married and subjected to a questionnaire. It included 21 questions assessing symptoms of allergic rhinitis to verify the diagnosis, and its frequency and severity. It also included the marital details and patterns of consanguinity. Results: Seven female patients (out of 24=29%) and 4 male ones (out of 25=16%) admitted experience of post coital exacerbation of allergic rhinitis attacks. Conclusion: Marriage and sexual activity are risk factors for allergic rhinitis as 18% of our study experienced post coital exacerbation of allergic rhinitis attacks. However, vasomotor rhinitis might be a possible diagnosis if the patient age is above 35 with no family history of allergies.

CONSANGUINITY AND INBREEDING COEFFICIENT IN TRIBAL PASHTUNS INHABITING THE TURBULENT AND WAR-AFFECTED TERRITORY OF BAJAUR AGENCY, NORTH-WEST PAKISTAN.

The north-western populations of Pakistan in the Federally Administered Tribal Areas (FATA) adjoining the Pakistan-Afghanistan border are an amalgamation of native and migrated Pashtun tribes. These tribal populations are in transition due to war conditions and geo-political turmoil on both sides of the border since the Soviet invasion in 1979. Bio-demographic and epidemiological data for these tribes are scarce. A prospective cross-sectional sample of 967 males was selected from a representative Pashtun population of Bajaur Agency, and information obtained on bio-demographic variables and marital union types. Analysis of these data revealed that consanguinity was 22.34% and the inbreeding coefficient F was calculated to be 0.0134. The inbreeding coefficient was observed to be higher in subjects who were illiterate, had unskilled jobs and who belonged to younger age categories, extended families and the Tarkalani tribe. Further analyses with respect to temporal variables like subject's age, year of marriage and age at marriage revealed that after a transition in marital union types in the early 80s, there has been a declining trend in the rate of consanguineous unions. Further, consanguineous unions in the parental generation were only 5%, but parental marriage types were predictors of subjects' marital union types. The data further establish that, contrary to a general notion about a high consanguinity rate in Pakistan, consanguineous unions are not common in Bajaur Agency and first cousin marriage is not the preferred type. Furthermore, this research shows that there is a great regional variation in the pattern of consanguinity in Pakistan that needs to be documented in order to draw a more comprehensive picture of the inbreeding coefficient in the country.

PATTERN OF CONSANGUINITY AND INBREEDING COEFFICIENT IN SARGODHA DISTRICT, PUNJAB, PAKISTAN.

Consanguinity is widespread in Pakistan. The majority of studies on consanguinity in Pakistan have been carried out in urban metropolitan areas, and data on rural populations are scarce. The present cross-sectional study was conducted in Sargodha district, upper Punjab, Pakistan where the majority of the population reside in rural areas. A random sample of 1800 married females belonging to six tehsils of Sargodha district was obtained and differentials in consanguinity rates and inbreeding coefficient (F) were investigated. The consanguinity rate was calculated to be 56.72% and the inbreeding coefficient was 0.0348. First cousin unions had the highest representation (49.11% of all marriages), and marriages up to distantly related/Biradari constituted 67.94% of all marriages. Among the six tehsils, consanguinity rates ranged from 50.38% in Bhalwal to 62.88% in Sillanwali. A high rate of consanguinity was observed in subjects speaking the Punjabi language, those with self-arranged/arranged-love marriages and those engaged in professional jobs. With respect to the occupation of husbands the highest consanguinity rate was found among landowners (77.59%; F=0.0539) and businessmen (62.62%; F=0.0377). However, consanguinity did not appear to be associated with rural/urban origin or literacy level. The data showed a wide variation in consanguinity rate and inbreeding coefficient across socio-demographic strata in the Sargodha district population. A comparison of Sargodha with other populations of Punjab also showed regional heterogeneity in the pattern of consanguinity, warranting further studies.

THE PRACTICE OF CONSANGUINEOUS MARRIAGE IN OMAN: PREVALENCE, TRENDS AND DETERMINANTS

The practice of consanguineous marriage has been the culturally preferred form of marriage in most Arab and the Middle Eastern countries, including Oman, but due to a paucity of population-based data in the past there is a dearth of information about its form and dynamics in Oman. Recent national-level surveys allow this gap to be filled. This paper examines the prevalence, trends and determinants of consanguineous marriages in Oman using data from the 2000 Oman National Health Survey. The results indicate a very high prevalence of consanguineous marriage in Oman, as more than half (52%) of marriages are consanguineous. First cousin unions are the most common type of consanguineous unions, constituting 39% of all marriages and 75% of all consanguineous marriages. The study observed various patterns of consanguinity, some of them common with other Arab nations, and some unique in nature. Women's age at marriage, employment, place of childhood residence and geographical region appear to be significant determinants of consanguineous marriages. Consanguineous marriage shows a strong association with marital stability, early age at marriage and early-age childbearing. There has been no appreciable change in the prevalence of consanguineous unions in Oman over the last four decades despite massive socioeconomic development and modernization. However, recent marriage cohorts show slight declining trends. The results suggest that consanguinity is likely to remain stable in the future or decline at a slow rate. Specific health education and genetic counselling should be followed in line with WHO recommendations to minimize the negative health consequences of consanguinity for child health.

The changing pattern of consanguinity in a selected region of the Israeli Arab community

The prevalence of consanguinity within the Israeli Arab community is relatively high, and is associated with high rates of inherited disorders that lead to a high frequency of morbidity and mortality. Data on consanguinity between couples were recorded during two periods (1980-1985 and 2000-2004) in relation to socioeconomic status of 4 selected villages. Two of the villages (A and B) are known to have high socioeconomic status, and the other two (C and D) are known to have low socioeconomic status. The average incidence of consanguineous marriages has slightly decreased from 33.1% in the first period to 25.9% in the second period (P = 0.0218) in all of the 4 villages. Marriages between first cousins showed a more significant decrease, from 23.9% in the first period to 13.6% in the second period (P < 0.0001). The average consanguinity rates of villages A and B were found to decrease from 22.3 to 16.2% respectively (P < 0.001) between the two observation periods, whereas those of villages C and D were found to decrease from 42.3 to 37.2%, (P < 0.001) during the same two periods. Thus, there has been a change in the pattern of consanguinity within the selected Israeli Arab villages, between the two study periods. This change seems to correlate with the sociodemographic status of the villages. Therefore, improving the socioeconomic status of the villages, as well as implementation of proper health education programs, is expected to have a positive effect in reducing consanguinity.

Ancestral Consanguinity and Mortality Among Three Endogamous Populations of Chittoor District, Andhra Pradesh, India

Consanguineous marriages have been practiced around the globe by many societies from time immemorial, particularly in South India. Consanguineous marriages play a major role in the health of a population, and diseases leading to mortality of the progeny are a consequence of detrimental recessive genes. To evaluate the effects of ancestral consanguinity on mortality in relation to consanguineous marriage, we have ascertained data from 1,500 women belonging to three endogamous communities (Akuthota Reddy, Odde, and Madiga) of Chittoor District, Andhra Pradesh, India. There were 500 women from each community. For each marriage we drew a family pedigree, extended upward to two earlier generations on either side of the spouses, to determine the prevalence and pattern of consanguinity, with detailed information on fertility and mortality. We observed a significant difference in the mortality rates between consanguineous and nonconsanguineous marriages when all the marriages of the women, women's parents, and (women's) husband's parents were considered in all three communities. In inbreeding, the offspring of earlier generations might have passed on deleterious genes to later generations (under unfavorable conditions), which resulted in a negative aspect of reproduction (among the offspring of the present couple).

Short ReportConsanguineous marriage in Iran

Consanguineous marriage is a major feature of family systems in south-west Asia. The aim of the present study was to determine the current prevalence and patterns of consanguinity in Iran as a means of assessing the associated requirement for genetic counselling services. Consanguinity was studied in 12 ethnic/religious populations, the Persians (Shi’a and Sunni), Kurds (Shi’a and Sunni), Lurs, Azaris, Baluchis, Zabolis, Turkamans, Bakhtiaris, Ghashghais and Arabs. A multi-stage sampling design was used with a representative total sample of 306 343 couples. The overall rate of consanguineous marriage was 38.6% with a mean inbreeding coefficient (α) of 0.0185. First cousin marriages (27.9%) were the most common form of consanguineous union, with parallel patrilateral marriage especially favoured. Statistically significant differences were observed in the prevalence and patterns of consanguinity between ethnic/religious populations and geographical regions. There also were significant differences for proportions of consanguineous marriages between Shi’a and Sunni populations within the same ethnic group. The highest rates of consanguineous union were in the least affluent sections of the population.

Estimation of inbreeding from ecclesiastical dispensations: application of three procedures to a Spanish case.

The inbreeding coefficient of a population, estimated from ecclesiastical Roman Catholic dispensations, results from the relative contribution of different degrees of relationships (uncle-niece, first cousin, etc.). The interpopulation comparisons of consanguinity patterns may be obscured by the fact that in 1918 the Roman Catholic Church norm regulating the closest marriageable kinship was modified, limiting the application for an ecclesiastical dispensation to relatives of third degree (second cousins) or closer. Depending on the length of the period before or after the change of regulation, coefficients and rates may differ. Deviation of frequencies for multiple marriages may also occur. The aim of the present paper is to determine how the chosen procedure based on ecclesiastical dispensations may affect results, regarding the inbreeding coefficient, the consanguinity rate, the structure of consanguinity and the close/remote kinship ratio. As a sample case, information from the Gredos mountain range (central Spain) has been used.

Consanguinity in Spain: socioeconomic, demographic, and geographic influences.

Information on consanguinity in Spain was reanalyzed in order to obtain a more complete picture of consanguinity patterns by considering temporal, geographical, demographic, and economic factors. To obtain data on consanguineous marriages, we reviewed 106 published references. Only populations with homogeneous geographical characteristics, economic activities, transportation facilities, and the like, were considered. Two-way analysis of variance (ANOVA) provided highly significant differences (p < 0.001) for a both for time periods and for urban versus rural patterns, but there was no interaction between the latter two. A regression analysis shows that for rural areas the geographic characteristics, economy, communications, and index of demographic tendency were significant predictors of the inbreeding coefficient. The results obtained indicate that urban and rural patterns differ significantly and that the temporal factor needs to be taken into account before comparing inbreeding coefficients. In urban areas the census size and altitude are included in the regression equation as significant variables, but association was not found between alpha and the index of demographic tendency (population increase or decrease). Instead, the absolute number of inhabitants (census size) was significant. In rural areas geographic characteristics, communications, and index of demographic tendency were significant predictors of the inbreeding coefficient.

An insight into recent consanguinity within the Basque area in Spain. Effects of autochthony, industrialization and demographic changes

The importance of studying the genetic kinship of those human groups characterized by a deeply rooted ethnicity has traditionally been and still is an interesting goal of anthropological and population genetic studies. However, only a few surveys have aimed to learn about the impact of industrial development on the consanguinity of these populations and even those have concentrated on industrialized regions. This approach is worth analysing in Spain, where industrialization was late in relation to other western European countries. In this work we analyse the characteristics of inbreeding in Guipúzcoa from 1951 to 1995. This Basque province underwent industrial and tourist development earlier than other Spanish regions. It has the highest density of Basque speakers and has always occupied a central position within the map of distribution of the Basque language. Guipúzcoa is geographically placed in the core of the Basque area. SUDJECTS AND METHODS: Data on consanguineous marriages recorded in the province of Guipúzcoa between 1951 and 1995 were taken from Roman Catholic dispensations stored in the Diocesan Archives of San Sebastián, the province's capital city. Over the whole time period, a total of 1152 consanguineous marriages were registered. The high frequencies of first cousin (M22) (F = 1/16) and uncle-niece, aunt-nephew (M12) (F = 1/8) consanguineous marriages distinguish Guipúzcoa from the rest of Iberian populations. The M22/M33 ratio (with M33 being second cousins) has never dropped below 0.67, which represents a significant deviation from the expectation value of 0.25. When consanguineous marriages are classified according to marriage partner birthplaces interesting results emerge. Provincial endogamy shows the highest consanguinity rates (57%) and the proportion of M22/M33 is also rather high (0.63). However, a major contribution to the consanguinity levels and mean inbreeding coefficient recorded in Guipúzcoa over recent decades has been made by immigrant relative groups coming from other geographical areas of Spain. In this segment of population the observed M22/M33 rates are 1.44. This study shows again how important preferentiality (or avoidance) is in human consanguinity, and also how human groups, in spite of being spatially settled in the same territory, present differential attitudes for given consanguinity patterns.

Knowledge, action and resistance: the selective use of pre-natal screening among Bedouin women of the Negev, Israel

The selective use of prenatal screening by Bedouin women attending Ministry of Health, maternal and child health clinics in Israel is examined. The data consist of a review of 537 prenatal care records, 16 in depth interviews with mothers, and four interviews with health personnel. These data are part of a larger study that took place between 1994–99 amongst Negev Bedouin women, part of the Palestinian Arab minority within Israel. The record review shows that the majority of women who attend prenatal care do not take up referrals for Maternal Serum Alpha Feto Protein (MSAFP) testing or for amniocentesis tests. Although many women interviewed talked about the value of prenatal screening, they also spoke of ‘false alarms’ that may result from testing. Similarly, women were aware that the socially preferred pattern of consanguinity in marriage amongst the Bedouin may cause medical problems, however test uptake was unrelated to consanguinity. There was a variety of views concerning the permissibility of terminating a pregnancy. This study shows that women use prenatal screening selectively in a way that helps them to balance social and medical risk.

Inbreeding effects in a coastal village and other parts of Andhra Pradesh.

A survey was carried out among fisher-women in Pallepalam, in Nellore District of Andhra Pradesh, to determine the prevalence and pattern of consanguinity and its effects on fertility, mortality, and morbidity. Of the 106 marriages investigated, 54.72% were consanguineous with predominant proportions of first cousin (36.79%) and uncle-niece (13.21%) marriages. The average inbreeding coefficients for autosomal and sex-linked genes were found to be 0.0405 and 0.0448 respectively. The differences between consanguineous and nonconsanguineous marriages were studied with respect to fertility, mortality and morbidity.

Consanguinity and demography in some Chilean populations.

Spatial and temporal changes in the rates and the patterns of consanguinity are studied in some (indigenous as well as admixed) populations of Chile. Relationship between the variation of infant mortality and late fetal death rates with the degree of inbreeding is also explored. The need of a temporal study of these demographic variables is also emphasized to elucidate the influence of marriage structure or determined reproductive patterns on the genetic and demographic aspects within these populations.