Fetal hepatic calcification in severe KAT6A (Arboleda-Tham) syndrome

: Arboleda-Tham syndrome (ARTHS, MIM 616268) is a rare genetic disease, due to a pathogenic variant of Lysine (K) Acetyltransferase 6A (KAT6A) with autosomal dominant inheritance. Firstly described in 2015, ARTHS is one of the more common causes of undiagnosed syndromic intellectual disability. Due to extreme phenotypic variability, ARTHS clinical diagnosis is challenging, mostly at early stage of the disease. Moreover, because of the wide and unspecific spectrum of ARTHS, identification of the syndrome during prenatal life rarely occurs. Therefore, reported cases of KAT6A syndrome have been identified primarily through clinical or research exome sequencing in a gene-centric approach. In order to expands the genotypic and phenotypic spectrum of ARTHS, we describe prenatal and postnatal findings in a patient with a novel frameshift KAT6A pathogenic variant, displaying a severe phenotype with previously unreported clinical features.