The majority of NETs are sporadic, although there are well-known genetic syndromes coexisting with NETs, such as multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 4 (MEN4), von Hippel–Lindau (VHL), neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC), but they constitute merely a small percentage of all NETs. The gene discussed is VHL; the disease is multiple endocrine neoplasia type 1.