Hereditary
palmoplantar keratoderma is a rare heterogenous group of genodermatoses characterised by hyperkeratosis of the palms and soles. Genetic alterations affecting
proteins of the
keratin cytoskeleton, cornified cell envelope, desmosomes and
gap junction proteins have been implicated in the pathogenesis of inherited
palmoplantar keratoderma. Reports of
palmoplantar keratoderma in the African population are scarce. Herein, we report a case of a 29-year-old HIV-infected African female, who presented to a tertiary hospital with complaints of a painful left fourth toe, secondary to a constriction band. Her background history is significant for prior constriction bands involving her toes, some of which progressed to auto-
amputations and childhood-onset thickening of the palmoplantar skin. Examination revealed diffuse transgrediens
palmoplantar keratoderma with associated clinical findings of pseudo-
ainhum and knuckle pads. A systemic workup was non-contributory. Next-generation sequencing genetic testing detected two variants of undetermined significance in
gap junction protein beta 4, a
connexin-encoding gene, and in the rhomboid 5 homolog 2 gene. Her phenotype remains discordant with our genetic findings. Her clinical features are instead consistent with overlapping phenotypes of
gap junction protein beta 2-related
connexin disorders:
Vohwinkel syndrome and
Bart-Pumphrey syndrome. Our case underlines the genetic heterogeneity of
palmoplantar keratoderma and the diagnostic challenges it presents. Our patient required
surgical amputation of the affected toe and is receiving ongoing dermatological management. Early recognition, appropriate referral and management are required to avert the debilitating consequences of
mutilating keratoderma and improve the quality of life.