Nagashima-Type Palmoplantar Keratosis with Compound Heterozygous Mutations in SERPINB7

Nagashima-type palmoplantar keratosis (NPPK) is a diffuse, non-syndromic (isolated), autosomal recessive palmoplantar keratoderma (PPK) with transgredients. It is characterized by non-progressive mild to moderate transgredient PPK. The mutation in SERPINB7 is reported to underlie the condition. Though many case reports/series have demonstrated various mutations in SERPINB7 , the genotype-phenotype correlation in this disorder is still lacking. We herein report two brothers with NPPK. Both patients were found to be compound heterozygous for c.796C>T and c.650_653delCTGT in the SERPINB7 gene. We then summarize the previously reported cases of different mutations in SERPINB7 along with their clinical phenotypes in an attempt to shed some light on this correlation. Further investigations and systematic data collection are still needed to clarify this issue.