3. CONCLUSION
This case of TOF-type APVS with was diagnosed at 14 weeks of gestation with an obvious PDA. 15 days later, the PDA narrowed down together with ectasia of PA. This progress indicated that the absent of PDA is not necessary for the survival of TOF-type APVS in utero, in contrast, the absent or restriction of PDA may be nothing less than adaptation to the disease. 20p12 deletion was found in this fetus. Prenatal diagnosis in early stage is conducive to reasonable clinical decision-making.