What are congenital disorders?
The World Health Organization (WHO) describes a congenital disorder (CD) or birth defect as an abnormality in the structure or function of a person, which is present from birth. Although CDs are present from birth, only some are obvious and can be detected when a baby is born. Others may only manifest later in childhood, adolescence or later in life.
For example, a neural tube defect (e.g. spina bifida) is obvious at birth, while haemophilia, which is also present at birth, may only become obvious and be diagnosed as the child grows.
Common CDs in specific populations of SA include albinism, neural tube defects, club foot, cleft lip/palate, Down Syndrome, haemophilia, cystic fibrosis, Fragile X syndrome, Duchenne muscular dystrophy and thalassemia.
Why do they happen?
Most CDs are caused by genetic factors and occur before a baby is even conceived. These include chromosomal abnormalities, single gene defects and multifactorial CDs (caused by genetic factors interacting with the environment). A small percentage of CDs are caused after conception, by teratogens (alcohol, drugs, maternal infections and illnesses). Serious CDs may be life threatening or lead to lifelong physical (including blindness and deafness) or intellectual disability.
Where do they occur?
CDs are a global problem and occur everywhere – but over 90% occur in middle- and low-income countries (MLIC), where 95% of those affected die as a result. This imbalance is due to poverty, poor maternal health and poor genetic services available in these countries. In MLIC, there is a higher percentage of older mothers and a higher rate of ‘consanguineous’ marriages (when close relatives marry), which increases the chances of having a child with a congenital disorder.
There is currently a lack of data on CDs in South Africa but modelled estimates indicate that just under 70 000 live births a year (almost 7%), or one in every 15 babies born, are affected by a CD.
Most of these CDS (80.5%) are caused by genetic factors and the rest (19.5%) by teratogens. Worldwide, teratogens are expected to cause only 10-15% of CDs. The increased rate in CDs due to teratogen exposure in SA is due to the fact that globally, SA has one of the highest documented rates of Fetal Alcohol Spectrum Disorder.
What’s the problem?
Many of those born with serious CDs in MLIC, including SA, die due to inadequate care. However, up to 70% of CDs could be prevented, cured or the disability reduced with relatively inexpensive, low-tech interventions. For example, the fortification of staple foods in SA with folic acid has resulted in a 30% drop in neural tube defects – a simple, low tech intervention that saves lives.
CDs are often not diagnosed, or are misdiagnosed, and their cause of death is often wrongly attributed. This has meant that there is no accurate data to demonstrate the true situation of CDs. This has prevented the CD burden of disease from being correctly assessed in many MLIC countries, including SA.
What can be done?
Genetic services ensure that people affected with CDs, or at risk of having children with CDs, can live and reproduce as normally as possible by receiving the diagnosis and ongoing treatment and support they require. These services should provide the ‘best possible patient care’ in the prevailing circumstances for those affected or at risk of CDs.
In SA, genetic services are in a state of decline due to other competing health priorities, including HIV/AIDS, which have redirected political will and funding. Genetic services, medical expertise and capacity need to be built up at all levels so that the needs of the growing population can be met with the best available care.
Raising awareness about congenital disorders is also necessary at all levels, including among policy makers – since without the required political will and accompanying funding the necessary genetic services will continue to dwindle.
What will happen if we do nothing?
Today in developed countries around the world, e.g. UK and USA, CDs are the leading cause of death and disability in children. SA is following this pattern and CDs are already causing a greater proportion of death and disability in children. With infectious diseases becoming better controlled it is essential that CDs are prioritised as a health care concern and that the shortfalls in genetic services are rectified.