We propose that, despite not being encompassed by small CNVs we used in comparative genomic mapping, the expression levels of the two ID candidate genes DENND5B, and ETFBKMT could be altered due to position effect125,126, providing a likely explanation for NDD phenotypes such as dystonia, global developmental delay, growth delay, motor delay, etc., observed in one DECIPHER proband DCP288321 (Fig. 2A and Table 3). Here, DENND5B is linked to Neurodevelopmental delay.