A congenital disorder is any medical condition that is present at birth. The term congenital does not imply or exclude a genetic cause. A congenital disorder can be recognized before birth (prenatally), at birth, or many years later. Congenital disorders can be a result of genetic abnormalities, the intrauterine environment, a mixture of both, or unknown factors.
Congenital conditions can be referred to as diseases, defects, disorders, anomalies, or simply genetic differences. The usage overlaps, but also involves a value judgement as to the harmfulness of the condition. In particular, people may disagree as to whether a specific physical anomaly should be considered a birth defect or a minor congenital anomaly. See human variability and disease for more on the occasional difficulties of drawing these distinctions.
A congenital disorder can have trivial or grave consequences. The most severe, such as anencephaly, are incompatible with life. Others, such as teratoma, vary from causing stillbirth to requiring fetal intervention or special delivery procedures such as the EXIT procedure, to needing surgery in the neonatal period. Congenital physical anomalies (birth defects) are a leading cause of death in early infancy, accounting for the deaths of nearly 2 out every 1000 infants in the United States.