16q24.3 Microdeletions Disrupting Upstream Non-Coding Region of Cause KBG Syndrome.

KBG syndrome is a multisystem developmental disorder characterized by macrodontia of the upper permanent incisors, distinctive facial features, a short stature, developmental delay, variable intellectual disability, and behavioral issues. Heterozygous chromosomal deletion encompassing the partial or entire gene, as well as the loss of function mutations, result in haploinsufficiency of the gene, leading to KBG syndrome. This indicates that precise levels of transcripts or protein are essential for human development. Here, we report three individuals who present with clinical features of KBG syndrome. These individuals carry microdeletions encompassing only the non-coding exon 1 of and its upstream region. Our molecular analysis showed that this deletion leads to reduction in the transcript and global transcriptome alterations similar to those seen in KBG syndrome patients. We concluded that microdeletions involving non-coding exon 1 of lead to KBG syndrome. Our study suggests the utility of transcriptome analysis in aiding the interpretation of novel copy number variants in the non-coding genomic region of .