A familial case of Bothnian palmoplantar keratoderma caused by the c.103T>G substitution in the AQP5 gene

Palmoplantar keratoderma is a clinically polymorphic disease with heterogenous etiology characterized by pronounced hyperkeratotic changes on the surface of the palms and soles. Hereditary forms of palmoplantar keratoderma are predominantly described by various variants in genes belonging to keratin family with autosomal dominant inheritance. A familial case of palmoplantar keratoderma is described. The analysis of family tree suggested autosomal dominant inheritance. Clinical manifestations included hyperkeratosis, xeroderma especially on the skin of the palms and feet: skin thickening with peeling and cracks, smoothed skin pattern. A previously undescribed and probably pathogenic c.103T>G variant of the AQP5 gene in heterozygous state in the proband, her mother and maternal grandfather was revealed as a result of whole genome sequencing. The presented clinical case is of interest for dermatologists due to the occasional incidence of palmoplantar keratoderma caused by variants in the AQP5 gene in clinical practice. Thus, the following diagnosis was established depending on the anamnestic data, clinical picture and examination results in the family: Bothnian palmoplantar keratoderma caused by a probably pathogenic variant in the AQP5 gene.