Precapillary pulmonary arterial hypertension in a patient with Proteus syndrome

Proteus syndrome is a rare progressive multisystem disorder characterized by asymmetric, disproportionate overgrowth of bone, skin, and other tissue types. Molecular pathogenesis has been identified as somatic activating mutations of the AKT1 gene. The presentation of Proteus syndrome is exceptionally variable. Respiratory complications include emphysematous lung disease and predisposition to pulmonary emboli, the latter of which is a significant source of mortality. Pulmonary hypertension due to longstanding hypoxic lung disease as well as chronic thromboembolic events has been observed in this population. In contrast, precapillary pulmonary arterial hypertension in the absence of chronic pulmonary emboli and parenchymal lung disease has not been described in the literature on patients with Proteus syndrome. We report such a case in a young patient with Proteus syndrome, reviewing subsequent management and emphasizing the need for a detailed investigation of dyspnea.