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The aim of the study was to determine whether consanguineous marriages result in reproductive wastage and an increased incidence of illness in the offspring in a community with a long history of inbreeding and an expected high rate of consanguineous marriage. A representative sample of 2200 women aged > or = 15 years from Dubai and Al Ain, two cities in the United Arab Emirates, representing on the one hand a modern metropolis and on the other a traditional society, were studied. A questionnaire, which included questions on age, parity, gravidity, number of stillbirths, number of abortions, number of children alive, neonatal deaths and specific illnesses in children, was administered by nurses in antenatal and gynaecological clinics in the two cities. The rate of consanguineous marriage was 50.5% and parity, gravidity, ages and number of children were similar in consanguineous and non-consanguineous groups. There was no significant difference in rates of abortion, stillbirth and neonatal death between the two groups. Overall, there was statistically significant higher reproductive wastage in consanguineous couples, but when the category of less than second cousins was excluded from the consanguineous group no difference was found in reproductive wastage between consanguineous and non-consanguineous marriages. Children born to consanguineous unions also had significantly higher incidences of illnesses (37.1%) than those of non-consanguineous unions (29%). The occurrence of malignancies, congenital abnormalities, mental retardation and physical handicap was significantly higher in offspring of consanguineous than non-consanguineous marriages. In conclusion, consanguinity did not result in reproductive wastage, but was found to be an important factor in the causation of specific illnesses in offspring.

Two sisters, products of a consanguineous marriage (with a total of 12 children) showed muscle weakness at ages 7 and 6 yrs, respectively. The symptoms progressed rapidly and the patients were confined to wheelchairs at ages of 12 and 11 yrs, respectively. They had mild facial weakness and pseudohypertrophy of the calves, but neither cardiomyopathy nor mental retardation. Serum CK activities exceeded upper normal limit by 70 to 85-fold. Muscle biopsies were compatible with muscular dystrophy. Both girls had a normal karyotype. The healthy mother had mild CK elevations in two out of three occasions, but the muscle biopsy was normal. Three out of the six unaffected sibs had mild CK elevations. The findings support the concept of severe progressive muscular dystrophy with autosomal recessive inheritance. The condition is clinically indistinguishable from Duchenne muscular dystrophy.

A family wherein 25 individuals, of whom 23 are affected and 2 are reputed to be affected with dentinogenesis imperfecta, is presented. The distribution of the patients which spans 5 generations in this pedigree accords well with autosomal dominant transmission of the disorder. A consanguineous marriage of 2 second cousins both of whom are affected has resulted in 4 offspring: unaffected, 2 affected with moderate severity and one with markedly severe involvement. These are held to correspond to 3 genotypic classes: homozygous lor the normal allele, heterozygotes, and homozygous for the mutant allele of dentinogenesis imperfecta, respectively. Relevant examples in other dominantly transmitted disorders of individuals affected with unusual severity, encountered among the progeny of matings between more typically affected parents and were thus presumed to be homozygotes, are also described. To our knowledge no instance of homozygosity for the dentinogenesis imperfecta gene has previously been described.

Marriage between close biological relatives is generally regarded with suspicion and distaste within Western society, reflecting historical and religious prejudice. By comparison, in many other populations there is a strong preference for consanguineous unions, most frequently contracted between first cousins, and marriage outside the family is perceived as a risky and disruptive option. The increasing importance of the genetic contribution to the overall disease profile in both developed and developing countries has highlighted potential problems associated with detrimental recessive gene expression in consanguineous progeny. This review examines the outcomes of consanguineous unions, with proposals as to how the ongoing preference for consanguinity in many communities can best be accommodated from a clinical genetics perspective.

To assess the trends in the frequency of consanguineous marriages in the Israeli Arab population in the last 40 years, we conducted a two-part study. For the first part, we re-analyzed data from a nationwide study carried out in 1992, and for the second part, we undertook a new survey in 1998 in four locations: Taibe, Tira, Kalansuwa and Kafr Bara. Data regarding the frequency of consanguineous marriage in these four locations for the years 1961-1985 was extracted from the original survey, and for the years 1986-1998, from new questionnaires. The frequency of consanguineous marriage was highest in the period 1961 1965 (50.6%), but by the period 1981-1985 it had decreased to 40.6%. Over the whole time span of the 1992 study, a significant decrease was observed between the periods 1961-1975 and 1976-1985 (p < 0.0001). In the four-location study, there was a significant decrease in the frequency of consanguineous marriage from 52.9%, in the period 1961-1970 to 32.8% in the period 1991-1998 (p = 0.0006). We conclude that the custom of consanguineous marriage in the studied population is still extremely high, and preventive measures should be taken to decrease its frequency and associated complications.

Two brothers, products of a consanguineous marriage, had severe hypoplastic genitalia and cardiomyopathy. These findings are similar to those of three other brothers of another consanguineous family who in addition had evidence of mental retardation. These five boys probably represent a previously undescribed syndrome of genetic origin but of poorly understood pathogenesis.

Grubben C, De Cock P, Borghgraef M, Van den Berghe H, Fryns JP. Severe pre- and postnatal growth retardation, developmental delay with hypotonia and marked hypertrophy of the distal extremities, dental anomalies and eczematous skin. A new autosomal recessive entity. Clin Genet 1992:41: 16–21. We report on three young children, two girls and one boy, with pre- and postnatal growth deficiency, hypotonia, psychomotor retardation with notably impaired speech development, hypotrophy of the distal extremities, small hands and feet, small and widely spaced teeth, eczematous skin, and, in two of them, a partial agenesis of the corpus callosum. To our knowledge this specific combination of features has not been reported before. Since the two girls are sisters and the boy is the product of a consanguineous marriage, the inheritance of this new syndrome appears to be autosomal recessive.

This study of 55,175 marriages in Turkey, conducted from 1970 to 1987, showed an overall rate of consanguineous marriage of 21.21% (mostly first-cousin liaisons) and an inbreeding coefficient of 0.0064532. However, considerable differences between areas are apparent.

Farber's disease (generalized lipogranulomatosis) is described in three affected siblings, products of a consanguineous marriage between first cousins. The clinical, laboratory, pathological and histochemical findings in one of these cases are reported in detail. This is the first recorded observation of Farber's disease in Iran.