the ATP-binding region). Furthermore, the consequent frame shift due to the small deletion led to a
premature stop codon 21 position downstream Q972 (at residue 993), resulting in a truncated protein
with nearly two thirds of the critical functional domains being lost, including the ATP-binding region, the
nucleotide binding region, the putative ion binding site, the phosphorylation site, and the BRK domain.
The predicted three-dimensional structure of wild type and truncated CHD7 protein (including the
chromo- and helicase domains, amino acids from 800aa–1600aa) were depicted in Fig. 5, indicating that
the mutant CHD7 induced by c.2916_2917del in the patient only maintains the chromodomains but lacks
all the other functional domains.