AUTHOR=Yoh Yuri , Shiohama Tadashi , Uchida Tomoko , Ebata Ryota , Kobayashi Hironobu , Okunushi Kentaro , Kato Mitsuhiro , Watanabe Kazuki , Nakashima Mitsuko , Saitsu Hirotomo , Hamada Hiromichi 

TITLE=Case report: Progressive pulmonary artery hypertension in a case of megalencephaly-capillary malformation syndrome

JOURNAL=Frontiers in Genetics

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2023.1221745

DOI=10.3389/fgene.2023.1221745

ISSN=1664-8021

ABSTRACT=<p>Megalencephaly-capillary malformation syndrome (MCAP, OMIM # 602501) is caused by hyperactivity of the thephosphoinositide-3-kinase (PI3K)–Vakt murine thymoma viral oncogene homolog (AKT)–mammalian target of rapamycin (mTOR) pathway, which results in megalencephaly, capillary malformations, asymmetrical overgrowth, and connective tissue dysplasia. Herein, we report the case of a 7-month-old girl with MCAP due to a <italic>PIK3CA</italic> somatic mosaic variant who presented with atrial tachycardia, finally diagnosed as pulmonary arterial hypertension (PAH). Oxygen therapy and sildenafil decreased pulmonary blood pressure and improved atrial tachycardia. Previous studies reported an association between the PI3K/AKT/mTOR pathway and abnormal pulmonary arterial smooth muscle cell proliferation, which may be associated with PAH. PAH should be considered a potentially lethal complication in MCAP patients, even when no structural cardiac abnormalities are identified in the neonatal period.</p>