Genetic birth defects a serious global problem 8/2/06. By the Public Health Genetics Unit A global survey of serious genetic conditions has reported that almost eight million children worldwide are born with a serious genetic defect each year.

The March of Dimes Global Report on Birth Defects: The Hidden Toll of Dying and Disabled Children , which is based on information on single-gene disorders, chromosomal disorders and physical malformations from 193 countries, found that overall around 6 per cent of babies are born with a serious genetic or partially genetic defect, the vast majority in poorer countries.

This is due to a range of factors including an increased incidence of consanguineous marriage, childbearing at relatively advanced maternal ages and a much higher rate of carrier status for certain genetic mutations where malaria is endemic (carrier status for the mutations associated with haemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency confers protection against malaria).

Many of these eight million children will die in early childhood and of those who survive, many more will be mentally and physically disabled.

The report lists the most common birth defects as congenital heart defects, neural tube defects (eg. spina bifida), haemoglobinopathies (eg. thalassaemia and sickle-cell anaemia), Down Syndrome and G6PD enzyme deficiency. Data on birth defects due to environmental causes were not included in the report, although some such as spina bifida are thought to have only a minor genetic component.

The combined worldwide birth prevalence of all genetic defects reportedly ranged from 39.7 per 1000 live births in high-income regions up to 82 per 1000 live births in low-income regions.

President of the March of Dimes (a voluntary US health agency concerned with improving the health of babies by preventing birth defects, premature birth and infant mortality) Dr Jennifer Howse said: "Our report identifies for the first time the severe, and previously hidden global toll of birth defects… This is a serious, vastly unappreciated and under-funded public health problem" (see BBC news report ).

The report proposes that introducing measures such as folic acid supplementation to prevent neural tube defects and iodination of salt to prevent severe congenital hypothyroidism could produce an immediate and significant reduction in morbidity (disability and ill-health) and mortality.

In the longer term, it recommends education of community, health professionals and policy makers in the most severely affected countries about minimising the risk of birth defects, and strengthening medical genetics services. This would include more training for health professionals, newborn screening programmes to identify babies born with metabolic disorders such as phenylketonuria (PKU), and efforts to identify couples at greatest risk of having children affected by genetic diseases.

"Building such services would allow nations to reduce the toll of death and disability from birth defects and to capitalise on the genetics revolution and rapid advances in molecular biology as they continue to unfold" Dr. Howse said.

Article courtesy of the Public Health Genetics Unit

Further reading

March of Dimes Global Report on Birth Defects: The Hidden Toll of Dying and Disabled Children