malformation

Malformation is a congenital anomaly resulting from abnormal development of tissues or organs during embryogenesis, leading to structural defects that are present at birth. Malformations arise during early morphogenesis and can affect nearly any organ system. They are distinguished from deformations, which result from mechanical forces altering a normally developing structure, and disruptions, which involve tissue loss due to external insults during development.

Causes are diverse and include genetic factors such as chromosomal abnormalities and single-gene mutations, as well as environmental influences such as teratogens, infections, maternal diabetes, or nutritional deficiencies. Many malformations have multifactorial etiologies, with gene–environment interactions contributing to risk.

Common examples of congenital malformations include neural tube defects (such as spina bifida and anencephaly), orofacial clefts, congenital heart defects, and limb malformations (e.g., polydactyly, syndactyly). Malformations may occur in isolation or as part of syndromes that involve multiple organ systems.

Diagnosis is usually established at birth, though prenatal screening and diagnosis (ultrasound, maternal serum screens, and diagnostic procedures such as amniocentesis or chorionic villus sampling) can detect many malformations before birth. Classification can be by affected organ system or by developmental mechanism (malformation versus deformation or disruption).

Management depends on the defect and may involve surgical correction, medical therapy, prosthetics, or multidisciplinary rehabilitation. Prognosis varies with severity, associated anomalies, and access to appropriate care. Prevention strategies include periconceptional folic acid supplementation to reduce neural tube defects, avoidance of teratogens, control of maternal health conditions, and genetic counseling where indicated.