Causal Variants of the GJB6 Gene are Associated with Hearing Loss and Skin Manifestations: A Case Report from Turkey

Abstract

Introduction: The gap junction beta 6 (GJB6) gene encodes connexin 30. This protein plays critical role in tissues and is responsible for the formation of gap junctions, which have a wide variety of physiological functions. Disease-associated variants of GJB6 cause non-syndromic hearing loss (HL) and skin lesions. We herein describe a Turkish girl who was diagnosed with HL and in whom genetic analysis revealed a causal variant of GJB6. Case presentation: The 1-year-old girl patient was diagnosed with bilateral HL when she was 1 month old. Apart from this, the patient’s motor/mental development and physical examination were normal. As a result of the analysis with the multi-gene panel, the causative genomic change, c.175G>A(p.Gly59Arg) in the GJB6 gene was determined as heterozygous. Segregation analysis proved the same genotype in the patient’s mother and grandfather. The patient’s mother and grandfather had bilateral HL and palmoplantar hyperkeratosis phenotype. The patient was diagnosed with Clouston syndrome, and genetic counseling was provided to her family. Discussion: Causal variants of GJB6 cause skin manifestations and signs of HL. Molecular diagnosis of these patients is a valuable tool for clinicians in reaching their optimal treatment and clinical management. Conclusion: In syndromic cases in which many organs are affected, the determination of the causative gene is important in directing the patients to appropriate observation, screening, and treatment strategies.