Diagnostic yield of chromosomal microarray to examine the genetic factors associated with fetal aberrant right subclavian artery

The primary objective was to find the risk factors that increase the probability of chromosomal abnormalities in fetal aberrant right subclavian artery (ARSA). Secondary objectives were to assess the factors which impact the adverse pregnancy outcomes in ARSA fetuses.

This retrospective study included a total of 104 pregnant women whose fetuses were diagnosed with ARSA from January 2020 to July 2024, with subsequent chromosomal microarray analysis (CMA) performed.

Among the 104 cases of ARSA in this study, 46 (44.2%) were classified as isolated ARSA and 58 (55.8%) as non-isolated ARSA. Classification of non-isolated ARSA based on ultrasound soft marker abnormalities and structural abnormalities showed that an increase in the number of combined ultrasound soft marker abnormalities was associated with increased fetal chromosomal abnormalities and pathogenicity. In fetuses with structural abnormalities and ultrasonographic soft markers, they have more microarray abnormalities and higher pathogenicity compared to ARSA with only a single soft marker. The chromosomal abnormalities in ARSA fetuses predominantly manifest as trisomy 21, partial segmental microduplications, and microdeletions. Logistic regression analysis indicated that the presence of ultrasonographic soft marker abnormalities alongside ARSA serves as a risk factor for adverse pregnancy outcomes in ARSA fetuses.

In contrast to isolated ARSA, chromosomal disorders indicate a significant risk in ARSA accompanied by ultrasound abnormalities, and the risk is closely related to the number of ultrasonographic soft marker abnormalities. In addition, the combination of ultrasonographic soft marker abnormalities was a risk factor for adverse pregnancy outcomes in ARSA, while maternal age, structural abnormalities, polyhydramnios, and intrauterine growth restriction were not associated with it.