A congenital disease, also known as a birth defect, is an abnormal condition that's present at birth. These conditions can be structural or functional anomalies that occur during pregnancy and can be identified before or at birth, or later in life. They can be inherited or caused by environmental factors.
Congenital diseases can range from mild to severe and can result in physical, intellectual, or developmental disabilities. Some common congenital diseases include:
- Cleft lip and palate
- Congenital heart disease
- Cerebral palsy
- Fragile X syndrome
- Down syndrome
- Spina bifida
- Cystic fibrosis
Causes
Genetic
A minority of congenital disorders are caused by genetic abnormalities i.e. chromosomal abnormalities (for example Down syndrome or trisomy 21) or single gene defects (for example cystic fibrosis).
Consanguinity (when parents are related by blood) also increases the prevalence of rare genetic congenital disorders and nearly doubles the risk for neonatal and childhood death, intellectual disability and other anomalies.
Socioeconomic and demographic factors
Low-income may be an indirect determinant of congenital disorders, with a higher frequency among resource-constrained families and countries. It is estimated that about 94% of severe congenital disorders occur in low- and middle-income countries. An indirect determinant, this higher risk relates to a possible lack of access to sufficient nutritious foods by pregnant women, an increased exposure to agents or factors such as infection and alcohol, or poorer access to health care and screening.
Maternal age is also a risk factor for abnormal intrauterine fetal development. Advanced maternal age increases the risk of chromosomal abnormalities, including Down syndrome.
Environmental factors including infections
Others occur because of environmental factors like maternal infections (syphilis, rubella, Zika), exposure to radiation, certain pollutants, maternal nutritional deficiencies (e.g., iodine, folate deficiency), illness (maternal diabetes) or certain drugs (alcohol, phenytoin).
Prevention
Preventive public health measures work to decrease the frequency of certain congenital disorders through the removal of risk factors or the reinforcement of protective factors. Important interventions and efforts include:
- Healthy diet including a wide variety of vegetables and fruit, and maintain a healthy weight
- Ensuring an adequate dietary intake of vitamins and minerals, particularly folic acid in adolescent girls and mothers
- Ensuring mothers avoid harmful substances, particularly alcohol and tobacco
- Avoidance of travel by pregnant women
- vaccination, especially against the rubella virus, for children and women