MicroRNA changes in maternal serum from pregnancies complicated by twin-twin transfusion syndrome: a discovery study.

OBJECTIVE: MicroRNAs (miRNAs) are used as biomarkers in cardiovascular disease and cancer. miRNAs are involved in placental development but have not previously been investigated in twin-twin transfusion syndrome (TTTS). Our aim is to explore the miRNA profile of TTTS pregnancies.

METHOD: Initial miRNA profiling was performed using a RT-PCR panel on maternal serum samples taken from 5 women prior to fetoscopic laser ablation for TTTS, and compared to serum samples from 5 women with uncomplicated monochorionic diamniotic twin pregnancies. Validation RT-PCR was performed in an additional cohort of 8 TTTS pregnancies and 8 uncomplicated pregnancies.

RESULTS: Median GA at sampling in the TTTS and control groups was 20+0 weeks (IQR:19+4 -20+0 ) and 20+2 weeks (IQR:20+0 -20+2 ) respectively. All samples passed quality control. One control sample was excluded as a biological outlier. 31/752 miRNAs were significantly different: 17 were up-regulated and 14 down-regulated in the TTTS group, although they did not remain significant following Benjamini-Hochberg correction for multiple testing. The 6 miRNAs chosen for validation demonstrated no significant difference.

CONCLUSION: This is the first study to investigate miRNA changes in TTTS pregnancies. We did not demonstrate a statistically significant difference in miRNAs in TTTS pregnancies, but further investigation is required.