Isolated familial pheochromocytoma as a variant of von Hippel-Lindau disease.

Inherited pheochromocytomas are often part of familial syndromes,
especially multiple endocrine neoplasia type 2 (MEN 2), retinal
cerebellar hemangioblastomatosis [von Hippel-Lindau (vHL) disease]
or neurofibromatosis type 1. It is not clear whether isolated
familial pheochromocytoma exists as a separate clinical entity. In
a family with pheochromocytomas in three generations and with at
least seven affected members, we investigated by clinical and
genetic analyses the presence or absence of associated conditions.
The clinical investigations included ophthalmological and
radiological studies for von Hippel-Lindau disease (magnetic
resonance imaging of the brain, computed tomography of the abdomen,
and direct ophthalmoscopy after mydriasis) and annual calcitonin
stimulation tests for C cell disease in five members who agreed to
regular follow-up. Besides the pheochromocytomas (so far, these
have been multiple in five of seven individuals) no definite second
associated condition was found. Genetic analysis did not identify
any MEN 2-specific RET protooncogene point mutations (which are
present in 97% of MEN 2a families). However, despite the complete
absence of other clinical manifestations of the vHL disease
(besides pheochromocytomas), a previously undescribed germline
missense mutation in the vHL tumor suppressor gene was found (C775G
transversion with a predicted substitution of a leucine by a valine
at codon 259 in the putative vHL protein). We conclude that in this
family the sole occurrence of pheochromocytoma is a variant of vHL
disease.