Identifying the Mutation via Diagnostic Exome Sequencing to Diagnose Say-Barber-Biesecker-Young-Simpson Syndrome in Three Generations of a Family.

Diagnostic exome sequencing (DES) is a powerful tool to analyze the pathogenic variants leading to development delay (DD) and intellectual disability (ID). Recently, heterozygous mutation of the histone acetyltransferase encoding gene has been recognized as causing a syndrome with congenital anomalies and intellectual disability, namely Say-Barber-Biesecker-Young-Simpson (SBBYS) syndrome. Here we report a case of SBBYS syndrome in a third generation Korean family affected with a missense mutation in , c.2292C>T p.(His767Tyr) identified by DES. This is the first confirmed familial inherited mutation of the reported worldwide. Our case emphasizes again the importance of basic physical examination and taking a family history. Furthermore, advances in genetic diagnostic tools are becoming key to identifying the etiology of DD and ID. This allows a physiatrist to predict the disease's clinical evolution with relative certainty, and offer an appropriate rehabilitation plan for patients.