The etiology of congenital abnormalities is multifactorial, involving genetic, environmental, and unknown factors. Genetic causes include chromosomal abnormalities like Down syndrome and single-gene mutations. Environmental factors include maternal infections (e.g., rubella), exposure to teratogens (e.g., alcohol, certain medications), and nutritional deficiencies (e.g., folic acid). In many cases, the precise cause remains unknown.
