Generalized pustular psoriasis with a novel mutation of interleukin-36 receptor antagonist, responding to methotrexate.

GPP: generalized pustular psoriasis IL-36RN: interleukin-36 receptor antagonist PV: psoriasis vulgaris INTRODUCTION Generalized pustular psoriasis (GPP) is a rare but serious inflammatory skin disease that may be caused by deficiency of interleukin-36 receptor antagonist in which there is presence of homozygous or compound heterozygous mutations of the IL-36RN gene. Most GPP cases are sporadic, although some may be autosomal recessive. A significant proportion of GPP without psoriasis vulgaris (PV) had homozygous or compound heterozygous mutations in IL-36RN. GPP alone is a distinct subtype and is etiologically distinguished from GPP with PV. Most GPP alone is caused by deficiency of the IL-36RN caused by IL-36RN mutations, in contrast to GPP associated with PV, in which this mutation is usually absent.