Easy Method for Keratin 14 Gene Amplification to Exclude Pseudogene Sequences: New Keratin 5 and 14 Mutations in Epidermolysis Bullosa Simplex

Keratin gene mutations in disorders of human skin and its appendages

“…This is analogous to the EBS phenotypes where mutations in the same location are associated with different phenotypes for mutations affecting K5 p.Iso183 [32, 62] as well as the K5 p.Val186 mutations [63, 64]. …”

“…Upon mild physical trauma, the keratin filament network is easily compromised, resulting in structural failure of the affected epithelial keratinocytes and loss of tissue integrity (reviewed in [14, 30]). The degree of severity of the clinical phenotype has been directly linked to the position of the pathogenic mutation along the keratin polypeptide backbone, although more recent reports provide some exceptions to this, whereby also milder disease phenotypes are caused by pathogenic mutations in the conserved hot spot region of the KRT genes [31, 32]. However, other additional factors may as well affect and exacerbate disease severity [33, 34].…”

“…Mutations in EBS-loc are most frequently found in four clusters lying outside of the helix boundaries of K5 or K14, including the non-helical L12 linker motif, or in the the amino-terminal homologous domain (H1) of K5, or in the 2B segment of K14 (see www.interfil.org; [8]. However, exceptions do exist and patients with mild phenotype (EBS-loc) have been identified with mutations in the conserved 1A and 2B helix hotspots [31, 32, 39]. Ultrastructural abnormalities of the cytoskeleton are far less severe than those seen in EBS-DM and some cases of gen-non-DM EBS.…”

Epidermolysis bullosa simplex due toKRT5mutations: mutation-related differences in cellular fragility and the protective effects of trimethylamineN-oxide in cultured primary keratinocytes

“…However, exceptions do exist and patients with a mild phenotype (EBS-loc) have been identified with mutations in the conserved 1A helix hotspot 5,6 as well as in the conserved 2B helix hotspot. 7 Although the position of the mutations can predict the clinical severity of EBS disease, the same does not hold true for cellular fragility in cultured cells, presumably because these cells are not under the same stress as cells within a tissue. In order to study the pathomechanisms at the subcellular level and to test new therapeutic strategies for EBS and other keratinopathies, an in vitro model exhibiting reproducible cellular phenotypes is required.…”

Keratin mutations in patients with epidermolysis bullosa simplex: correlations between phenotype severity and disturbance of intermediate filament molecular structure

“…A different mutation at this codon (KRT14-p.Leu136Gln) was reported previously in relation to the EBS-WC phenotype. 42 The duplication p.Gln374_Leu387dup (14) is localized in the highly evolutionarily conserved 2B domain of keratin 14 and the mutation p.Val143Ala in the nonhelical V1 head domain of keratin 5. Comparison of the correspond- ing amino acids at position 143 with other type II keratins shows that the valine residue is highly conserved and present in all 26 type II keratins; the substitution KRT5-p.Val143Asp was described in an EBS patient.…”