De novo variants of dominant monogenic disorders in Vietnam detected by a noninvasive prenatal test: a case series

Background: Noninvasive prenatal tests for monogenic diseases (NIPT-SGG) have recently been reported as helpful in early-stage antenatal screening. Our study describes the clinical and genetic features of cases identified by NIPT-SGG. Materials & methods: In a cohort pregnancy with abnormal sonograms, affected cases were confirmed by invasive diagnostic tests concurrently, with NIPT-SGG targeting 25 common dominant single-gene diseases. Results: A total of 13 single-gene fetuses were confirmed, including Noonan and Costello syndromes, thanatophoric dysplasia, achondroplasia, osteogenesis imperfecta and Apert syndrome. Two novel variants seen were tuberous sclerosis complex (TSC2 c.4154G>A) and Alagille syndrome (JAG1 c.3452del). Conclusion: NIPT-SGG and standard tests agree on the results for 13 fetuses with monogenic disorders. This panel method of screening can benefit high-risk Vietnamese pregnancies, but further research is encouraged to expand on the causative gene panel.