SERPINB7 and palmoplantar keratoderma, Nagashima type: Nagashima-type palmoplantar keratoderma (NPPK) is an autosomal recessive disorder caused by biallelic loss-of-function variants in the <i>SERPINB7</i> gene, whereas Hashimoto's thyroiditis (HT) is a common autoimmune endocrine disease.