[Prenatal ultrasound and genetic characteristics of fetuses with Kabuki syndrome: A report of six cases and literature review].

Objective: To explore the clinical and genetic characteristics of fetuses with Kabuki syndrome (KS) and their genotype-phenotype correlation.

Methods: A retrospective analysis was carried out on the prenatal manifestations and results of genetic testing of six KS fetuses diagnosed by whole-exome sequencing (WES). The findings were compared with 28 prenatally diagnosed KS cases reported in the literature to summarize the prenatal features of KS. This study has been approved by the Ethics Committee of Maternal and Child Health Care Hospital of Hubei Province (Ethics No.: 2025-141-01).

Results: Prenatal ultrasound findings in KS fetuses showed high heterogeneity. The most common abnormalities were cardiac (23/35, 65.7%) and renal (20/35, 57.1%), which are often accompanied by amniotic fluid abnormalities (5/35, 14.3%), single umbilical artery (5/35, 14.3%), and fetal hydrops (4/35, 11.4%). Among the six fetuses from our center, all were identified by WES to harbor pathogenic variants of the KMT2D gene, and all of which were de novo. These included 3 frameshift variants, 2 nonsense variant, and 1 missense variant, among which 4 were unreported previously.

Conclusion: This study has expanded the mutational spectrum of the KMT2D gene. Prenatal ultrasound findings of KS lack specificity, though multi-system anomalies or specific soft markers may indicate KS. WES is an effective tool for the diagnosis, and KS should be included in the differential diagnosis list for prenatal cardiac and renal abnormalities.