Fig. 2

Pedigree, clinical phenotypes and mutation analysis in family 2741. a Pedigree of family 2741 with congenital mixed hearing impairment and sensorineural hearing impairment cases (Affected subjects are denoted in black. Arrow indicates the proband. Mutation carrier are denoted with dot within a symbol); b Audiograms of both ears for the proband, who exhibited typical audiometric features of mixed hearing impairment; c Temporal bone CT images of the proband demonstrating dilation of the bottom of the IAM and a deficit in the bony plate, which separates the basal turn of the cochlea and the IAM (arrow); d Audiograms of both ears from the uncle of the proband, who shows profound sensorineural hearing impairment; e Temporal bone CT images of the uncle of the proband demonstrating dilation of the lateral end of the IAM and bone deficiency between the basal turn of the cochlea and the IAM (arrow). f Wild-type sequence of POU3F4 including position 973; g A heterozygous c.973delT mutation was found in the female carriers; h A hemizygotic c.973delT mutation was detected in the affected males; i Amino acid change caused by changes in the DNA sequence leading to a predicted frameshift mutation and truncation of the POU3F4 protein; j Panel 1 marks the position of the c.973delT (p.Trp325Glyfs*12) mutation and panel 2 marks the position of the c.927delCTC (p.Ser310del) mutation. The POU homeodomain (from Gly276 to Arg335) is highly conserved in different species