Whole-exome sequencing applications in prenatal diagnosis of fetal bowel dilatation

Abstract

This study introduced whole-exome sequencing (WES) in prenatal diagnosis of fetal bowel dilatation to improve the detection outcome when karyotype analysis and copy number variation sequencing (CNV-seq) were uninformative in detecting pathogenic variants. The work reviewed 28 cases diagnosed with fetal bowel dilatation and analyzed the results of karyotype analysis, CNV-seq, and WES. Among the 28 cases, the detection rate in cases with low risk of aneuploidy was 11.54% (3/26), which is lower than 100% (2/2) in cases with high risk of aneuploidy. Ten low-risk aneuploidy cases with isolated fetal bowel dilatation had normal genetic testing results, while the remaining 16 cases with other ultrasound abnormalities were detected for genetic variants at a rate of 18.75% (3/16). The detection rate of gene variation was 3.85% (1/26) by CNV-seq and 7.69% (2/26) by WES. This study suggested that WES could reveal more genetic risk in prenatal diagnosis of fetal bowel dilatation and has value in prenatal diagnosis to reduce birth defects.

Sonographic findings of transient marked proximal bowel dilatation in a growth-restricted fetus at 35 weeks’ gestation

“…The differential diagnosis of etiologies underlying the relatively infrequent third-trimester sonographic depiction of dilated fetal bowel includes (functional or mechanical) bowel obstruction, intestinal atresia, volvulus, annular pancreas, intestinal malrotation, intussusception, gastrointestinal duplications, cystic fibrosis-associated meconium ileus, congenital chloride diarrhea, microvillus inclusion disease, intestinal neuronal dysplasia, and meconium plug syndrome [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] . Fetal bowel obstruction may be associated with aneuploidy (mostly Trisomy 21 in association with esophageal or duodenal atresia), and rarely select microduplications or deletions, with a detection rate in cases of low risk of aneuploidy of 3.85% by copy number variation sequencing (CNV-seq) in contrast to 7.69% by whole exome sequencing (WES) [12] , [13] , [14] , [15] . In addition, conditions associated with dilated loops of fetal bowel include a small subset of conditions in which this finding may be transient, which although prominent when seen, may dissipate with spontaneous resolution [ 16 , 17 ].…”