Von Hippel-Lindau syndrome (VHL) is characterized by hemangioblastomas of the brain, spinal cord, and retina; renal cysts and clear cell renal cell carcinoma; pheochromocytoma and paraganglioma; pancreatic cysts and neuroendocrine tumors; endolymphatic sac tumors; and epididymal and broad ligament cystadenomas. Retinal hemangioblastomas may be the initial manifestation of VHL and can cause vision loss. Cerebellar hemangioblastomas may be associated with headache, vomiting, gait disturbances, or ataxia. Spinal hemangioblastomas and related syrinx usually present with pain. Sensory and motor loss may develop with cord compression. Renal cell carcinoma occurs in about 70% of individuals with VHL and is the leading cause of mortality. Pheochromocytomas can be asymptomatic but may cause sustained or episodic hypertension. Pancreatic lesions often remain asymptomatic and rarely cause endocrine or exocrine insufficiency. Endolymphatic sac tumors can cause hearing loss of varying severity, which can be a presenting symptom. Cystadenomas of the epididymis are relatively common. They rarely cause problems, unless bilateral, in which case they may result in infertility.

Pulmonary venoocclusive disease-2 is an autosomal recessive subtype of primary pulmonary hypertension (PPH; see 178600). It is characterized histologically by widespread fibrous intimal proliferation of septal veins and preseptal venules, and is frequently associated with pulmonary capillary dilatation and proliferation. The disorder can cause occult alveolar hemorrhage. High-resolution CT imaging of the chest shows patchy centrilobular ground-glass opacities, septal lines, and lymph node enlargement (summary by Eyries et al., 2014). For a discussion of genetic heterogeneity of pulmonary venoocclusive disease, see PVOD1 (265450).

Primary pulmonary hypertension-6 (PPH6) is characterized by markedly elevated pulmonary arterial hypertension, associated with reduced oxygen saturation and diffuse ground-glass opacities on chest x-ray. Lung biopsy shows thickening of the alveolar septae and abnormally proliferating capillaries (Postma et al., 2023). For a general phenotypic description and a discussion of genetic heterogeneity of primary pulmonary hypertension, see PPH1 (178600).