Earlier today, the March of Dimes issued a comprehensive report on birth defects. The report, written by Arnold Christianson, Christopher Howson, and Bernadette Modell, estimates that every year an estimated 7.9 million children (6% of total births worldwide) are born with a serious birth defect of genetic or partially genetic origin (see here for the press release, here for the executive summary, and here for the full report). The report provides a thorough and useful overview of the problem and is important reading.

At least 3.3 million children under the age of five die from birth defects each year, and an estimated 3.2 million may be disabled for life. Birth prevalence from country to country ranges from a high of 82 per 1,000 to a low of 39.7 per 1,000 live births worldwide. More than 90 percent of all infants with a serious birth defect are born in middle- and low-income countries. But the main impetus for the report stems from this fact:

Up to 70% of the birth defects that occur could either be prevented or the children affected offered care that would be lifesaving or significantly reduce disability.

The report ranges from the five most common serious birth defects of genetic or partially genetic origin (congenital heart defects, neural tube defects, the hemoglobin disorders, Down syndrome, and glucose-6-phosphate dehydrogenase deficiency), to common recessive disorders (cystic fibrosis, oculocutaneous albinism), to congenital infections (toxoplasmosis, syphilis, varicella-zoster, rubella, cytomegalovirus, herpes simplex virus), to birth defects arising from maternal malnutrition or exposure to teratogens (spina bifida, congenital hypothyroidism, fetal alcohol syndrome), to factors influencing the global distribution of birth defects (malaria, consanguineous marriage, parental age, migration, poverty).

The authors note several misperceptions that in their view have made birth defects a relatively low priority for donors and health care agencies. First, health policy makers have not been aware of the extent of death and disability attributable to birth defects. Second, there has been the belief that effective care and high-tech interventions are beyond the means of low- and middle-income countries (on this score they cite heartening advances in preventing and treating sickle cell anemia in Nigeria, thalassemia in Iran, and neural tube defects in China). Finally, they cite the belief that attention to birth defects will draw funding away from other high priority maternal and child health efforts. On this last point, they note the obvious cost effectiveness of relatively straightforward measures like folic acid fortification of food to prevent neural tube defects, which not only prevents 500-550 cases per year in the US, but is estimated to save approximately $400 million annually as well.

Recommendations? Here’s a partial list:

Educate the community.

Promote family planning.

Ensure a healthy, balanced diet during a woman’s reproductive years.

Control infections in women of reproductive age.

Optimize maternal health.

Train physicians and nurses in recognizing birth defects and in the essentials of medical genetics.

Establish child health services to care for infants with birth defects.

Establish national capacity for surveillance and monitoring.

Promote lay support organizations.

Establish peri-conception medical services.

Implement pre-conception or prenatal medical genetic screening to identify couples at risk.

Establish newborn screening for metabolic disorders.

An ambitious agenda, no doubt, but the examples of success that the authors cite suggest that many of these goals are achievable.

One particularly interesting topic, in my view, is that of consanguineous marriage. The authors note that it’s accepted by a minimum of 20 percent of the world’s population, largely in the Eastern Mediterranean, North Africa, and South India. As a result, they report this striking estimate: at least 8.4 percent of the world’s children have related parents. Given that the risk for serious disability and/or neonatal and childhood death is almost doubled for the offspring of first cousins, this is a major factor in the incidence of birth defects (this is demonstrated clearly in the report’s Figure 5, comparing the incidence of birth defects in British Pakistanis with Britons of North European descent). It isn’t clear from the report that the authors view a reduction in consanguineous marriage as a realistic part of the overall strategy to combat birth defects, but given its impact, it’s hard to see how it can be avoided.

Read the whole thing.