A: Schematic representation of the 29-exon OTOA gene. The first exon is non-coding. Italic bold exons (2, 5, 16, 17): locations of OTOA MLPA probes. Dashed grey rectangle: segmentally duplicated region of OTOA sharing high level of sequence identity with OTOAP1. The especially high level of identity between exons 23 to 29 of OTOA and exons 3 to 9 of OTOAP1 make the CNVs detection unreliable.