Although metastatic PPGLs showed more loss of SDHB staining than non-metastatic PPGLs in the present study, 6.3% of WD PPGLs also showed negative SDHB staining, and 6 of 11 (54.5%) PPGLs with a loss of SDHB staining were non-metastatic. The gene discussed is SDHB; the disease is Wilson disease.