Prenatal Diagnosis of Arboleda-Tham Syndrome Associated With KAT6A Variants Presented With Interrupted Inferior Vena Cava and Fetal Growth Restriction.

Arboleda-Tham syndrome (ARTHS) is an autosomal dominant disorder characterized by core features of developmental delay and intellectual disability. While ARTHS has been documented in numerous postnatal patients, only a limited number of prenatal cases have been reported to date. We present three prenatal cases of KAT6A-related ARTHS. One case exhibited an interrupted inferior vena cava with azygos continuation to the superior vena cava at 24 weeks gestation. Two cases demonstrated retarded fetal growth during the third trimester. All three cases underwent invasive genetic investigations during pregnancy, and trio exome sequencing identified a de novo pathogenic variant in the KAT6A gene in the fetuses. The pregnancies were subsequently terminated. Our report contributes to the expansion of both the genotypic and phenotypic spectrum of ARTHS by detailing previously unreported prenatal clinical features and novel genetic variants. Furthermore, our study emphasizes that even nonspecific findings on prenatal ultrasound may warrant exome sequencing, as it provides significant benefits for families by facilitating timely diagnosis and enhancing clinical management.