Monitoring for these AESIs was informed by the clinical presentation of a rare, autosomal recessive condition, Papillon‐Lefèvre syndrome, in which the genetic absence of DPP1 results in diffuse palmoplantar keratoderma and severe periodontitis with premature tooth loss of both deciduous and permanent teeth.15 Here, CTSC is linked to diffuse palmoplantar keratoderma.