Congenital heart defects--the risks to offspring

Epidemiology of cardiovascular malformations: prevalence and risk factors

Epidemiological approaches to the study of cardiovascular malformations (CVMs) face challenges of disease definition, nomenclature, changing diagnostic methodologies, the rarity of the disease in the general population, and the incorporation of current knowledge on genetics and morphogenesis into designing studies to investigate risk factors and implement preventive strategies. Previous studies, especially the population-based Baltimore-Washington Infant Study, have documented variability in the prevalence of specific types of CVM by time, place, and personal characteristics and have highlighted the potential prevention of diabetes-associated heart malformations through timely medical management of pre-conception diabetes. Left-sided obstructive heart defects have been identified as targets for new studies of genetic risk factors. Potential environmental risk factors for CVMs also have been identified, such as organic solvents and pesticides, coincident with the emergence of new strategies to study genetic susceptibility and gene-environment interactions. Increased collaborative, multicenter research on these and other factors, such as nutritional factors in early pregnancy, offers new hope for potentially reducing the burden of CVM in the population.

Inbreeding and congenital heart diseases in a north Indian population

The study was performed in six mohallahs (colonies) of Aligarh City (North India). All six mohallahs are predominantly inhabited by Qureshi (meat sellers, a highly endogamous group) Muslims. A total of 1721 infants and children up to the age of 6 years were examined to determine the incidence of congenital heart diseases (CHD) in relation to the degree of consanguinity of the parents. Around 43% of the subjects were the offspring of consanguineous marriages including second-cousin, first-cousin-once-removed and first-cousin. A higher percentage of CHD was found in the offspring of consanguineous marriages: about 3.37% out of 741 children as compared to 1.22% in 980 offspring of non-consanguineous marriages, whereas in the first-cousin offspring, the percentage of CHD rose to 4.41%. The differences were found to be statistically significant. The present study suggests a genetic influence and also casts doubt on the applicability of a polygenic threshold model to all forms of cardiac malformation.