GTF2I and Williams syndrome: The derived alleles are located within or proximal to three genes: two TE insertions in intron 1 of Williams-Beuren Syndrome Chromosome Region 17 (WBSCR17), the lack of an insertion in intron 17 of the General Transcription Factor 2-I (GTF2I), and one insertion in intron 5 of POM121 Transmembrane Nucleoporin (POM121) [27].