[Prenatal diagnosis of a fetus with Rubinstein-Taybi syndrome].

Objective: To explore the clinical characteristics and variant of CREBBP gene in a fetus with Rubinstein-Taybi syndrome (RSTS).

Methods: A fetus with RSTS diagnosed at the Third Affiliated Hospital of Zhengzhou University in August 2022 was selected as the study subject. Clinical data, amniotic fluid sample of the fetus and peripheral blood samples of its parents were collected for whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing.

Results: Foot malformation, cerebellar vermis agenesis, brain agenesis, polysyndactyly of the big toes and other phenotypes were found by prenatal ultrasound. WES revealed that the fetus has harbored a heterozygous c.4684G>T (p.E1562*) variant in exon 28 of the CREBBP gene (NM_004380.3), which was de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was predicted to be pathogenic (PVS1+PS2_Moderate+PM2_Supporting). After genetic counseling, the couple had opted to terminate the pregnancy and refused autopsy of the fetus.

Conclusion: The c.4684G>T (p.E1562*) variant of the CREBBP gene probably underlay the RSTS in this fetus. The newly discovered variant has enriched the mutational spectrum of the CREBBP gene and illustrated that WES is an efficient tool for the prenatal diagnosis of RSTS.