Prior to 2000, three different familial and syndromic diseases were known to result in PGL and/or PH: MEN-2 induced by germline inactivating mutations in the RET proto-oncogene; VHL disease due to mutations in the tumor suppressor gene VHL; and NF1 caused by mutations in the NF1 gene. This evidence concerns the gene NF1 and multiple endocrine neoplasia type 2.