PMC5109563_01
Chronic cutaneous symptoms before (a) and after (b) cholecystectomy. (a) Blisters, erosions, crusts and milia on the back of the hands are observed. (b) The cutaneous symptoms improved except for pigmentation at 3 years after cholecystectomy.
1349-7235-55-2965-g001.jpg
PMC5109563_01_1349-7235-55-2965-g001.jpg
g001
He presented with a 3-year history of chronic blistering on the backs of his hands due to photosensitivity, and he had developed skin fragility, blisters and scarring (Fig. 1a). Chronic blistering on the backs of his hands due to photosensitivity had also completely improved at this time (Fig. 1b).
Analyses of the p.G14R mutation of the PPOX gene. (a) Missense mutation of a heterozygous G C transition in exon 2 of the PPOX gene. (b) Sequence alignment of the PPOX enzyme from Homo sapiens (HS), mouse (MM), Rattusnorvegicus (RN), Xenopuslaevis (XL), Drosophila melanogaster (DM) and Nicotiana tabacum (NT). Residue numbers and secondary structures are based on human PPOX. Conserved residues are highlighted in red. The arrow indicates the amino-acid change found in our patient. (c) Predicted three-dimensional (3D) structures of the wild-type (blue) and p.G14R mutated (green) type of PPOX at the N-terminal betaalphabeta domain and their superimposition. Predicted amino-acid sequences were modelled to the 3D structure using I-TASSER software (17), and figure drawings were carried out using Swiss-PdbViewer (18). The region of amino acid 14 is shown in red. Hydrogen bonds are shown as yellow dashed lines. In the merge image, side chains of amino acids are represented by the same colors with their structures. This model shows that a p.G14R mutation would loosen an alpha1-helix and warp beta1-sheet, which thus causes an extension of the loop between them (black dashed line). The side chain of mutational amino acid arginine is sticking out over alpha1 helix of the PPOX (arrow), while the side chain of wild type amino acid glycine has no projection.
1349-7235-55-2965-g002.jpg
PMC5109563_01_1349-7235-55-2965-g002.jpg
g002
Sequencing analyses using polymerase chain reaction primers, identified a heterogeneous novel c.40G>C mutation in exon 2 of the PPOX gene (Fig. 2a).