Erythrokeratoderma variabilis caused by a recessive mutation in GJB3

Area of Science:

• Genetics
• Dermatology
• Molecular Biology

Background:

• Erythrokeratoderma variabilis (EKV) is a rare disorder of cornification.
• It is typically linked to dominant mutations in GJB3 and GJB4 genes, encoding connexins (Cx)31 and Cx30.3.
• These connexins are crucial for epidermal gap junction formation.

Observation:

• A consanguineous family of Middle Eastern origin presented with recessive EKV.
• Genetic analysis identified a novel missense mutation (c.G88A) in the GJB3 gene.
• This mutation leads to an isoleucine to valine substitution at position 30 (p.V30I) in the connexin 31 protein.

Findings:

• The identified p.V30I mutation in GJB3 was found to be the molecular basis of recessive EKV in this family.
• In vitro studies demonstrated that the p.V30I mutation impairs the ability of connexin 31 to reach the cell membrane.
• This impairment prevents the formation of functional gap junctions.

Implications:

• Autosomal recessive inheritance is a possible mode of EKV transmission, particularly in consanguineous populations.
• Genetic counseling for families at risk of EKV should consider recessive inheritance patterns.
• Understanding the molecular basis of EKV expands knowledge of connexin function and epidermal biology.