Which of the following is an example of a disruption anomaly in fetal development?

• A. Congenital amputations caused by amniotic bands
• B. Neural tube defects from folate deficiency
• C. Chromosomal abnormalities such as Down syndrome
• D. Cleft palate due to inherited facial structure

Answer: (A)

Disruption anomalies occur when an external factor interrupts a structure that has already begun to develop, causing irregular outcomes or loss of tissue. Amniotic bands can entangle a developing limb and constrict growth, blood flow, or tissue formation, leading to congenital amputations. This external disruption interrupts what was already forming, rather than starting from a faulty formation itself. In contrast, neural tube defects from folate deficiency reflect problems in the formation process, chromosomal abnormalities like Down syndrome arise from genetic material issues, and cleft palate results from failed fusion during normal development. Thus, amniotic-band–related limb disruption is the clearest example of a disruption anomaly.