IDC10= Q80.3 (Congenital bullous ichthyosiform erythroderma).
Genomic coordinate (human 12:52,644,558 KRT2).
Cytoband (human 12q13.13 KRT2).
Intraband %= KRT2 @45.4%
OMIM’ genes @12q13.13 = 31 genes.
Polymorphs = 243 KRT2 variants in ClinVar.
Hyperbolic Umbilic Chromosome-12 is 1,200 genes.
Here I 🎁 present: “Siemens Ichthyosis Bullosa”, Victor McKusick, Mendelian Inheritance in Man’, 1966.
INTRODUCTION.
Siemens Ichthyosis Bullosa (IBS), an autosomal dominant disorder of keratinization caused by pathogenic variants in the KRT2 gene.
Pathophysiology and Biomechanics.
Genetic Defect: Mutations occur in the KRT2 (Keratin-2) gene cluster on cytoband 12q13.13.
Structural Impact: The defect disrupts the K2/K10 keratin filament network specifically in the upper epidermis (stratum granulosum and upper spinous layers).
Mechanical Instability: Minor mechanical stress or shear/friction easily pushes the tissue past its Instability Threshold (Cusp Region). This leads to superficial cleavage and subcorneal blister formation.
Diagnostic Hallmark.
The Mauserung Phenomenon: Also known as “molting,” this characteristic clinical feature involves the spontaneous or trauma-induced peeling of superficial epidermal sheets, leaving behind localized, shallowly denuded paths of healthy-looking skin bordered by dark gray hyperkeratoses.
