Differential Diagnosis of Pulmonary Veno-Occlusive Disease and/or Pulmonary Capillary Hemangiomatosis after Identification of Two Novel EIF2AK4 Variants by Whole-Exome Sequencing

Background: Pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH) are rare causes of pulmonary hypertension. Pulmonary arterial hypertension (PAH) and PVOD/PCH are clinically similar, but there is a risk of drug-induced pulmonary edema when PCH patients receive the PAH therapy. Therefore, early diagnosis of PVOD/PCH is important. Objectives: We report the first case in Korea of PVOD/PCH in a patient carrying compound heterozygous pathogenic variants in the EIF2AK4 gene. Case Description and Method: A 19-year-old man who was previously diagnosed with idiopathic PAH suffered from dyspnea on exertion for 2 months. He had a reduced lung diffusion capacity for carbon monoxide (25% predicted). Chest computed tomography images showed diffusely scattered ground-glass opacity nodules in both lungs with an enlarged main pulmonary artery. For the molecular diagnosis of PVOD/PCH, whole-exome sequencing was performed for the proband. Results: Exome sequencing identified two novel EIF2AK4 variants, c.2137_2138dup (p.Ser714Leufs∗78) and c.3358-1G>A. These two variants were classified as pathogenic variants according to the 2015 American College of Medical Genetics and Genomics guidelines. Conclusions: We identified two novel pathogenic variants (c.2137_2138dup and c.3358-1G>A) in the EIF2AK4 gene. Identification of possible pathogenic gene variants by whole-exome sequencing or panel sequencing is recommended as a guide to adequate treatment of patients with pulmonary hypertension.