Coinheritance of generalized pustular psoriasis and familial Behçet-like autoinflammatory syndrome with variants in IL36RN and TNFAIP3 in the heterozygous state.

Generalized pustular psoriasis (GPP) is now known to be caused by biallelic variants in IL36RN and monoallelic variants in CARD14 and AP1S3. The presence of a modifier locus or oligogenic inheritance have been hypothesized. We report on a patient with a unique coinheritance of pathogenic variants in IL36RN (c.115+6T>C) and TNFAIP3 (c.547C>T, p.R183*) causing the genetic entities GPP and familial Behçet-like autoinflammatory syndrome (AISBL). The heterozygous variant in IL36RN identified by Sanger sequencing was inherited from his unaffected father, while the heterozygous variant in TNFAIP3 was detected by whole-exome sequencing and was also identified in the patient's AISBL-affected maternal relatives. Further functional studies are required to research whether the variant of TNFAIP3 plays a part in the development of GPP or simply causes the Behçet's disease phenotype. However, our data suggest that whole-exome sequencing for the heterozygous carrier of the IL36RN gene in GPP be used to find the potential second genetic locus.