Genetic analysis of malformations causing perinatal mortality

Genetic analysis of lethal congenital malformations causing perinatal mortality at Nizwa Hospital, Oman

An analysis of lethal congenital malformations (LCM) - which contributed to perinatal mortality at Nizwa Hospital, Oman - is presented for a 10-year period from January 1993 through December 2002. Single gene, chromosomal or multifactorial inheritance accounted for 86.1% of the cases. LCM-related perinatal deaths were higher in Omani, compared to those in non-Omani births (p < 0.001). This could possibly be attributed to high consanguinity, low female literacy and high fertility rates in the Omani population. Forty per cent of LCM-related perinatal deaths in the study had potential options for prevention. Integration of a community-based genetic service into the existing health-care delivery system is suggested.

Clinical, genetical, radiological, and anatomopathological survey of 17 patients with lethal osteochondrodysplasias

Seventeen patients thought to have lethal osteochondrodysplasias were evaluated. Diagnosis was established through clinical evaluation, radiological studies and necropsy. Genetic counseling was provided to the affected patient's families. Specific diagnosis was confirmed in 16 cases. Nosologic diagnosis was done through clinical evaluation. However, the most efficient method for verifying the diagnosis was a skeletal radiological study. This fact corroborates the orientation of the International Classification of Osteochondrodysplasias (International Working Group on Constitutional Disease of Bone, 1992) in which a radiological criterion was adopted as the most relevant for classification of osteochondrodysplasias. An anatomopathological study was also done to detect internal anomalies, and was effective in identifying abnormalities in epiphyseal growth plate in a bone fragment study. This method had low specificity, but in two cases it was especially decisive for diagnostic differentiation.

Effect of ethnic origin of mother on fetal outcome

The outcome of 11046 infants, from 20 weeks' gestation, born to mothers of different ethnic origins within one London borough has been analysed. There was no difference in perinatal death rates between the Asian and white infants. Among those with mothers from Africa and the West Indies there were overall significantly more intrauterine deaths (26.8/1000 and 20.0/1000) and neonatal deaths (8.6/1000 and 9.6/1000) than for the white mothers (intrauterine deaths 8.3/1000; neonatal deaths 3.7/1000). At less than 28 weeks', gestation specific death rates were similar in all groups and the overall higher death rates were due to an increase in the proportion of preterm deliveries among the black mothers. From 28 to 36 weeks' gestation, black infants born alive had lower neonatal death rates (7.7/1000) than the white infants (19/1000). The cause of the increased incidence of preterm labour among the black mothers is uncertain, though differences in intrauterine infection rates may be an important factor.

Perinatal mortality in different ethnic groups

We have analysed the cause of perinatal deaths in four hospitals in the North West Thames region over a six year period commencing January 1980. The Pakistani population had a significantly greater perinatal mortality rate (15.7/1000 births) than the Europeans (11.3/1000 births). This was due to an increased incidence of macerated stillbirths and lethal malformations, the latter resulting from a significantly higher incidence of autosomal recessive disorders, neural tube defects, and renal malformations.

The epidemiology and service implications of congenital and constitutional anomalies in ethnic minorities in the United Kingdom

The literature on the incidence in the UK of congenital and constitutional anomalies in populations deriving from Africa, the Caribbean, the Far East, the Indian subcontinent and the Mediterranean is reviewed. These groups represent an increasing proportion of the whole child population. Comparison with the white population and between groups reveals that the burden of impairment varies with country of origin. Some of the reasons implicated include different gene frequencies and mating patterns, age/parity distribution and uptake of preventive services. Comparisons with prevalence at birth in the countries of origin are made where possible. In general, populations with high rates in their country of origin retain their high rates (e.g. central nervous system anomalies among births to parents deriving from the Indian subcontinent). There is a general lack of data on the prevalence of handicapping conditions such as cerebral palsy, as well as the associated health needs and service utilisation amongst ethnic minorities.

Lethal malformations and perinatal mortality: a 10 year review with comparison of ethnic differences

During 1976 to 1985 perinatal mortality in Leicestershire decreased from 21 to 9.5 per 1000 births. Throughout this period the incidence of lethal malformations, excluding neural tube defects, remained relatively constant at around 1.8 per 1000 births. Analysis of the malformations present in 201 lethally malformed babies showed that 147 (73%) had a disorder carrying a recurrence risk of 1% or greater. Only 7% of these malformations might have been predicted from the family history or advanced maternal age. The incidence of lethal malformations was significantly increased in the Asian population, largely because of an excess of autosomal recessive disorders. The contribution of lethal malformations to perinatal mortality has almost doubled over the past 10 years and is likely to increase despite prenatal diagnosis and improvements in obstetric and paediatric services.

Etiological heterogeneity in sirenomelia

Two babies with sirenomelia are described. Case 1, one of twins, showed the full sirenomelia sequence in conjunction with atelencephaly and cebocephaly. Case 2 had malformations consistent with a diagnosis of the VATER association. Review of the literature indicates that the basic defect in sirenomelia and the VATER association lies in the formation and differentiation of mesodermal tissue and that sirenomelia, the VATER association, and monozygotic twinning show a complex etiological interrelationship.