Fig. 2

a The chromatogram and schematic representation of wild-type and mutated sequences illustrate the disrupted acceptor splice site at position − 1 of intron 26, which lead to a frameshift in the cDNA sample. b A comparative sequence alignment produced by ClustalO of the CHD7 protein across seven evolutionarily distant species. Frameshift of 23 new amino acids and therefore a truncated 1869 amino acid sequence is highlighted in red. Below the protein sequences is a key denoting conserved sequence (*), conservative variants (:), semi-conservative variants (.), and non-conservative variants (). c 3D model of the BRK domain, which is absent in the patient. Picture produced by the LiteMol program [33]. d A schematic representation of the CHD7 protein, which is 2,997 amino acids in length, with the arrangement of the main domains: two chromodomains (green), SNF2 domain (red), helicase domain (blue), and two BRK domains (yellow). A schematic view was adopted from the Pfam protein domain database