A novel pathogenic frameshift variant of KAT6B identified by clinical exome sequencing in a newborn with the Say-Barber-Biesecker-Young-Simpson syndrome

Abstract

Say-Barber-Biesecker-Young-Simpson Syndrome (SBBYSS; OMIM 603736), which overlaps with the originally described Ohdo syndrome (Verloes, 2006), is an autosomal dominant disorder, clinically recognizable at birth. Classical features are blepharophimosis with ptosis, epicanthus inversus, long thumbs/great toes, cryptorchidism, congenital heart defects, and variably cleft palate and thyroid dysfunction (Clayton-Smith, 2011; Campeau, 2012). SBBYSS has been shown to be due to heterozygous KAT6B mutations. KAT6B [OMIM 605880] is located on chromosome 10q22.2 and encodes a highly conserved histone acetyltransferase involved in chromatin modification (Clayton-Smith, 2011). Overlap with the Genito-patellar syndrome (GPS) is possibly due to different mutations of the KAT6B gene (Campeau, 2012). Most reported SBBYSS cases were sporadic, however, at least one family with affected individuals in three generations has been described (Kim, 2012).The purpose of this work was to report a so far novel KAT6B mutation in a further patient with the SBBYS syndrome.