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).     

Consanguineous marriages in the province of Antalya, Turkey

To assess the trends in the frequency and the medical effects of consanguinity in the south coast of Turkish population using local and national data in the last 11 years. This cross-sectional study was carried out in Manavgat province, which is a major tourism center on the Mediterranean coast of Turkey. The authors studied consanguineous marriages in rural and urban population in the Mediterranean coast, Manavgat province, Turkey, via a 1500 random survey sample of married couples. There has been a significant increase in the incidence of consanguineous marriages in rural areas (40.7%) since 1989 in the southern population of Turkey. The results showed that the most frequent type of marriage was between the first cousins. It is found that there is no statistically significant difference between the consanguineous and non-consanguineous marriages in the different age groups. The results were discussed on the basis of educational status, reasons for having consanguineous marriages and the general medical effects as well as with the relation of congenital malformations. The custom of consanguineous unions in the Mediterranean population of Turkey is still extremely high, and preventive measures should be done to decrease its frequency and associated complications.     

Consanguineous marriage and reproduction in Beirut, Lebanon.

Effects of consanguineous marriages on couples' fertility and on offspring mortality were investigated in Beirut through a population-based health survey of 2,752 households. A multistage random sampling procedure was used, and information was obtained from all ever-married women in the household about their reproductive performance and genealogical relationship with spouse; demographic and socioeconomic information was also recorded. Twenty-five percent of all marriages were between relatives, and the spouses were first cousins in approximately 57% of all consanguineous marriages. Total pregnancies, live births, and living children were significantly higher among consanguineous couples than among nonconsanguineous ones, as was the proportion dead among children ever born. However, no difference remained in either fertility or mortality, when allowance was made for socioeconomic status, religious affiliation, and marriage duration. The issue of confounding is discussed, and the lack of significant pattern in the final analysis is interpreted as resulting from a long-term practice of consanguineous marriages.     

Local differences in the Archbishopric of Santiago de Compostela (Galicia, Spain) in relation to the consanguinity structure, 1900-1979

The microgeographic variability of consanguinity in the Archbishopric of Santiago de Compostela (Galicia) between 1900 and 1979 was studied. This Archbishopric covers 106 local councils integrated by 964 parishes, of which 677 (70.23%) were analyzed. Of the 307,094 marriages counted within this period, 15,739 corresponded to weddings between biologically related couples. Within the Archbishopric, eight geographical regions were considered: six coastal regions (Golfo Artabro, Berganti?os, Fisterra, Xallas, Santiago Oeste, and Rías Baixas) and two inland regions (Santiago Este and Terra de Montes). In order to evaluate the differences and similarities among them, the frequencies of all types of marriages (consanguineous and nonconsanguineous) were considered. First, a hierarchical grouping of the regions based on their chi-squared distances was performed. Then, in order to analyze relationships that are exclusively due to the structure of consanguinity, a correspondence analysis was performed and only the frequency of the different types of consanguineous marriages was taken into account. The results from both statistical analyses indicate special features of the Xallas region, both in the level of inbreeding (8.75%, the highest in the Archbishopric) and in the structure of consanguinity, for which a high proportion of uncle-niece marriages was found (6.22% of all consanguineous marriages). In all cases the structure of consanguinity provides informative nuances on the differences and similarities among population groups.     

新疆伊犁五个少数民族的近亲结婚

1983年4月至1984年5月,对新疆伊犁哈萨克自治州五个民族的近亲结婚情况进行了调查。调查的婚姻数为维吾尔2553起,哈萨克1079起,回1235起,锡伯1222起,蒙古446起。近亲结婚率与平均近交系数分别为:维吾尔——8.23％与 46.74×10~(-4),回——8.10％与45.07×10~(-4),锡伯——4.66％与24.93×10~(-4),哈萨克——2.87％与11.31×10~(-4)。蒙古——0.45％与 2.80×10~(-4)。解放以来,维吾尔族与回族的近亲结婚率有上升趋势,而锡伯族的则有下降趋势。各族近亲结婚中大部分为亲表亲结婚,但堂亲结婚在维吾尔族的近亲结婚中竟占26.18％,在回族中也占16.00％。1303名近亲结婚子女中的七岁前死亡率(12.89％)及先天性缺陷与遗传性疾病发生率(2.99％)显著高于6370名非近亲结婚子女的相应值(7.65％及0.38％)。     

Inbreeding patterns in La Cabrera, Spain: dispensations, multiple consanguinity analysis, and isonymy

Marital structure and inbreeding coefficients were analyzed in La Cabrera, an isolated mountain region in northwestern Spain. A total of 5,714 marriages were celebrated from 1880 to 1989 in the 37 parishes of the area. The total frequency of consanguineous marriages (up to the fourth degree) is 23.05%; multiple consanguineous marriages are remarkably common, reaching 5.43% of the total. The first cousin/second cousin ratio (referred to as kinship-type frequencies) is 0.43. The inbreeding values are the highest recorded in Spain and in Europe: alpha3 is 4.82 x 10(-3) for the whole period and alpha4 is 6.78 x 10(-3) for 1880--1919. The temporal trend of inbreeding shows high values (alpha3 > 4.5 x 10(-3)) for a particularly long period (1900--1959) and a rapid decline from 1960 onward. This historical inbreeding trend is clearly related to changes in population size. The frequencies of multiple consanguineous marriages and the analysis of isonymy show that the inbreeding structure is related to geographic and demographic factors. Comparing the results at two hierarchical levels (La Cabrera as a whole and the 37 parishes individually), we conclude that the inbreeding values are affected by internal geographic subdivision of the population (Wahlund effect). Social and cultural factors, such as avoidance of or preference for consanguineous marriages, are less important but depend on the kinship type involved.     

Arthrogryposis, ectodermal dysplasia and other anomalies in two sisters.

Ectodermal dysplasia with arthrogryposis is an uncommon condition. We describe two daughters of a distant consanguineous couple with oligodentia, enamel abnormalities, camptodactyly, longitudinally broken nails, growth retardation, joint contractures with amyotrophy, hypohidrotic skin with tendency to excessive bruising and scarring after injuries and scratching, kypho-scoliosis, mild facial dysmorphia and microcephaly. The condition is probably due to an autosomal recessive gene, the parents being gypsies of the same ancestral origin.     

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.     

Sociodemographic correlates of consanguineous marriage in the Muslim population of India

Using data derived from the 1992-1993 National Family Health Survey, the sociodemographic characteristics of consanguineous marriage were determined in the Muslim population of India. In this nationally representative sample of 8436 women, consanguineous marriages accounted for 22.0% of the total. No differences between the consanguineous and non-consanguineous groups were observed in terms of mean age at marriage or mean age at cohabitation. The study confirmed the negative association between consanguineous marriage and maternal education but also indicated that women in consanguineous unions were more likely to be employed, albeit mainly in agricultural work on behalf of the family. Consanguineous couples more frequently lived in smaller towns and in an extended family environment. Somewhat conflicting results were obtained with indicators of socioeconomic status, but the overall picture suggested that consanguineous households had greater access to consumer goods because of their larger number of co-resident persons.     

Community perceptions of reasons for preference for consanguineous marriages in Pakistan

Although the recent Pakistan Demographic and Health Survey (DHS) show that two-thirds of marriages in Pakistan are consanguineous, the sociocultural determinants of such marriages remain largely unexplored. This paper examines the relative importance of the three commonly perceived reasons for such marriages: religious, economic and cultural. The analysis is based on qualitative data collected in 1995 from multi-ethnic and multi-religious communities in Karachi, the largest city of Pakistan. Results show that consanguineous marriages are preferred across all ethnic and religious groups to a varying degree, and that parents continue to be the prime decision-makers for marriages of both sons and daughters. The major reasons for a preference for consanguineous marriages are sociocultural rather than any perceived economic benefits, either in the form of consolidation of family property or smaller and less expensive dowries. Among Muslims, following religious traditions is the least commonly cited reason for such marriages. Despite the reported sociocultural advantages of consanguineous marriages, such unions are perceived to be exploitative as they perpetuate the existing power structures within the family.     

Parental consanguinity as a cause for increased incidence of births defects in a study of 238,942 consecutive births.

The risk for birth defects in the offspring of first-cousin matings has been estimated to increase sharply compared to non consanguineous marriages. As a general decline in the frequency of consanguineous marriages was observed in this century, one wonders whether consanguinity is still a factor in the appearance of birth defects in developed countries. Based on our registry of congenital anomalies we tried to answer to this question. In the population studied in North-Eastern France a consanguineous mating was known in 1.21% of the cases with congenital anomalies, vs. 0.27% in controls, (p < 0.001). The frequency of the malformations recorded paralleled the degree of consanguinity: out of 89 malformed children, 51 were seen in first-cousins mating (10.3 times more frequent than in offspring of non consanguineous couples), 17 in second-cousins marriages and 18 in more distant relatives mating. Three were uncle-niece marriage. Excluding known mendelian conditions these numbers were 73, 36, 17 and 17 respectively and the corresponding relative risk were 3.68, 3.01, 3.41 and 4.89 respectively. Therefore there is a negative dose-response effect between level of inbreeding and risk of congenital malformations. Consanguineous mothers were more often pregnant than non consanguineous mothers (p < 0.01) and they had more stillbirths than non consanguineous mothers. These results show that consanguinity is still a factor of birth defects and they must be taken into account for genetic counseling of inbred marriages, in developed countries.     

Trends of consanguineous marriages in a Sunni Muslim population of West Bengal, India

The Muslim population of the Chaltaberia village in the district of South 24 Parganas in West Bengal is divided into several wards (paras) inhabited by people of specific surnames. The frequency of endogamous marriages within surnames is greater than randomly expected ones. An incomplete reproductive isolation is observed among the five dominant surnames. Consanguineous marriages occur more often outside the village than inside. Leaving out marriages between long distances, a small median distance of 6.36 km is recorded. The neighborhood area works up to be 552.2 km2, which is rather small. There is an underlying process of breeding isolation by distance. A generation length of 21 years has been used for examining the temporal change in consanguineous marriages and inbreeding, which generally appears to increase. There is a general trend of decline in consanguineous marriages towards the southern part of West Bengal and eastern part of Assam among the Bengalee Muslims. The frequency of consanguineous marriages is 7.3% out of all marriages (N=1153) that have taken place in six generations in the population. The first cousin marriage is nearly 50% of all marriages. Patrilineal marriages are common in marriages between second and third cousins. An increase of consanguineous marriages in the younger generation was observed, but the total frequency agrees with a general trend of a decline in the frequency of consanguineous marriages among the Muslims in this part of India.     

Effects of consanguineous marriages on fertility among three endogamous groups of Andhra Pradesh

To assess interrelationships between consanguineous marriage and fertility, 3 caste groups in Andhra Pradesh--the Desuri Kapu, an affluent agricultural caste; the Devanga, an artisan caste in the middle range of the hierarchy; and the Mala, a scheduled caste at the bottom--were selected for field study. Consanguineous marriages are an essential part of the social structure in this area of southern India. A total of 2524 marriages were analyzed, of which 46% were consanguineous. 19% of consanguineous marriages were between uncle and niece, 22% were between 1st cousins, and 5% were between more distant cousins. The Devanga had the highest rate of related marriages (48%), followed by the Desuri Kapu (47%) and the Mala (41%). Higher caste individuals, and wealthier persons within each caste, are more likely to marry relatives so they can avoid splitting their properties through dowry of bride price. The consanguineous unions as a whole were significantly more fertile than nonconsanguineous unions. The mean number of pregnancies, live births, and surviving offspring was 4.85, 4.44, and 2.99, respectively, among consanguineous couples compared with 3.41, 3.32, and 2.87, respectively, among nonconsanguineous couples. Although the number of pregnancies and live births was significantly higher among consanguineous couples in all 3 castes compared with nonconsanguineous couples, the difference in the number of surviving children between consanguineous and nonconsanguineous unions was not significant among the wealthier castes. This suggests that child mortality is higher among the offspring of consanguineous unions, despite their greater wealth.     

Inbreeding and immigration in urban and rural zones of Chile,with an endogamy index

Abstract

From ecclesiastical and civil data on consanguinity, age at marriage, and immigration in Chile from 186S to 1914, comparisons between urban and rural zones are made. A random mating deviation index is developed, and the values indicate deviation toward endogamy in both zones. These values show an inverse relation to those of the exogamy index developed by Freire‐Maia and Freire‐Maia (1963). Values in the rural zone are double those in the urban zone. In the two zones there are no clear differences in age at marriage between consanguineous and nonconsanguineous couples. Thus, we might expect lower fertility in consanguineous marriages only because of a higher probability of homozygosis of deleterious genes.     

A search for the primary abnormality in adult-onset type II citrullinemia.

Deficiency of argininosuccinate synthetase (ASS) causes citrullinemia in human beings. Type II citrullinemia is found in most patients with adult-onset citrullinemia in Japan, and ASS deficiency is found specifically in the liver. Previous studies have shown that the decrease of hepatic ASS activity is caused by a decrease in enzyme protein with normal kinetic properties and that there were no apparent abnormalities in the amount, translational activity, and gross structure of hepatic ASS mRNA. In the present work, we show by sequencing analysis that there was no mutation in the ASS mRNA from two patients with type II citrullinemia. We also report RFLP analysis of a consanguineous family with type II citrullinemia, by using three DNA polymorphisms located within the ASS gene locus. In spite of having consanguineous parents, the patient was not a homozygous haplotype for the ASS gene. The RFLP analysis of 16 affected patients from consanguineous parents showed that 5 of 16 patients had the heterozygous pattern for one of the three DNA probes and that the frequency of the heterozygous haplotype was not different from the control frequency. These results suggest that the primary defect of type II citrullinemia is not within the ASS gene locus.     

Homozygous mutations in PXDN cause congenital cataract, corneal opacity, and developmental glaucoma

Anterior segment dysgenesis describes a group of heterogeneous developmental disorders that affect the anterior chamber of the eye and are associated with an increased risk of glaucoma. Here, we report homozygous mutations in peroxidasin (PXDN) in two consanguineous Pakistani families with congenital cataract-microcornea with mild to moderate corneal opacity and in a consanguineous Cambodian family with developmental glaucoma and severe corneal opacification. These results highlight the diverse ocular phenotypes caused by PXDN mutations, which are likely due to differences in genetic background and environmental factors. Peroxidasin is an extracellular matrix-associated protein with peroxidase catalytic activity, and we confirmed localization of the protein to the cornea and lens epithelial layers. Our findings imply that peroxidasin is essential for normal development of the anterior chamber of the eye, where it may have a structural role in supporting cornea and lens architecture as well as an enzymatic role as an antioxidant enzyme in protecting the lens, trabecular meshwork, and cornea against oxidative damage.     

云南九个民族中的近亲结婚调查

对云南9个民族[傣、哈尼、彝、布朗、基诺、拉祐、苦聪(人)、回、汉]共11,589起婚姻作了调查。发现:(1)城、乡之间,各民族与地区之间,近婚率差异极显著。(2)许多民族的近婚率均较国内发达地区同一民族高。(3)姑舅亲、倒姑舅、两姨亲及3/2表亲占9个民族近婚总数的84.7％。(4〕9个民族的平均近交系数同样较国内发达地区同一民族高,其中苦聪人的平均近交系数(0.018579)是目前国内最高数值之一,即使平均近交系数最低的汉族(0.001935)也明显高于北京、湖北宜昌和上海市区的汉族的平均近交系数。     

Two female siblings with a previously unreported MCA/MR syndrome: pre- and postnatal growth retardation, iris colobomata, spasticity, facial dysmorphism and dilated ventricles.

We report two siblings from non consanguineous parents with a similar MCA/MR syndrome: Pre- and postnatal growth retardation, microcephaly, mental retardation, iris colobomata, facial dysmorphism, spasticity, dilated ventricles and abnormal immunoglobulin levels. Review of published reports and the use of the London Dysmorphology Database suggests that these siblings may present a new syndrome.