16p11.2 de novo microdeletion encompassing SRCAP gene in a patient with speech impairment, global developmental delay and behavioural problems

Abstract

We describe a patient with speech impairment, global developmental delay, behavioural problems and a 186 kb de novo microdeletion on 16p11.2. There are four OMIM Phenotypes entries partially overlapping with the deleted region and related to recurrent microdeletions/microduplications in 16p11.2. A detailed review of published data shows that microdeletions/microduplications' boundaries do not include genes that are deleted in the case here reported. The deletion encompasses 9 RefSeq genes and includes SRCAP (Snf2-related CREBBP activator protein, OMIM*611421), a disease causing gene. Recently, truncating mutations in the SRCAP gene have been shown to cause Floating-Harbor syndrome (FHS, OMIM#136140), a rare disorder characterized by peculiar facial features, short stature with delayed osseous maturation and speech impairment. The patient reported here shows few subtle phenotypic features resembling that of FHS, but she does not have sufficient signs and symptoms for the clinical diagnosis and a clinical classification based on facial gestalt is not possible. This is the first report of a 16p11.2 deletion completely removing one copy of SRCAP, suggesting that haploinsufficiency of this gene could be associated to speech impairment, global developmental delay, behavioural problems and few subtle phenotypic features resembling FHS. However, further evidence for the putative causative role of SRCAP isolated deletion is needed.