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palmoplantar keratoderma, Bothnian type (PPKB) - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

palmoplantar keratoderma, Bothnian type

MONDO:0010849

Also known as:PPKB

Overview

GeneticsAutosomal dominant · AQP5 (chr 12)

Clinical Presentation

Features include: Diffuse palmoplantar hyperkeratosis.

Organ System	Phenotype Count	Example Features
Skin	1	Diffuse palmoplantar hyperkeratosis

Explore clinical features

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

AQP5 encodes aquaporin 5 (265 aa). Aquaporins form homotetrameric transmembrane channels, with each monomer independently mediating water transport across the plasma membrane along its osmotic gradient. Highest expression in Testis (538.2 TPM) and Minor Salivary Gland (252.8 TPM).

Palmoplantar keratoderma, Bothnian type is associated with mutations in the AQP5 gene on chromosome 12.

The AQP5 protein participates in RHAG transports CO2 from extracellular region to cytosol, RHAG transports CO2 from cytosol to extracellular region, and AQP1 tetramer transports CO2 from extracellular region to cytosol pathways.

AQP5 is classified as a druggable target (Ion Channel and Transporter categories) with score 1.7.

Diagnosis

Genetic testing for AQP5 is available. Testing is considered confirmatory for diagnosis.

Prognosis

Estimated prevalence: 1-9 in 100,000 (Uncommon).

Data assembled from 5 of 12 sources · Last updated Sep 20, 2026, 9:38 AM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:600231

Orphanet

European rare disease database

Orphanet:2337

GARD

Genetic and Rare Diseases Info Center

GARD:1862

Questions for Your Care Team

→Should I pursue genetic testing for AQP5, and what would the results mean for my family?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

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palmoplantar keratoderma, Bothnian type

Overview

Clinical Presentation

Explore clinical features

Genetic Landscape

Diagnosis

Prognosis

Medical References

External Resources

OMIM

Orphanet

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team