Pulmonary arterial hypertension in familial hemiplegic migraine with ATP1A2 channelopathy

Abstract

To the Editor: Pulmonary arterial hypertension (PAH) has been the focus of major research in recent years [1]. Involvement of mutations in genes encoding for members of the transforming growth factor-β signalling pathway ( BMPR2 , ACVRL1 , ENG and SMAD8 ) has been demonstrated in the development of heritable PAH, allowing novel experimental and clinical approaches [2–4]. However, ∼30% of familial forms of PAH remain without any identification of genetic mutations. Recently, mutations of the KCNK3 gene (encoding K+ channel subfamily K member 3) have been reported in patients with familial and sporadic PAH [5]. KCNK3 belongs to a family of mammalian K+ channels, and are involved in the regulation of resting membrane potential, pulmonary vascular tone and in vascular remodelling. This result paves the way to the involvement of novel signalling pathways in the development of heritable PAH. Herein, we describe a novel association of PAH and a channelopathy due to mutation in ATP1A2 (encoding the α2-subunit of the Na+/K+-ATPase), a mutation known to cause familial hemiplegic migraine (FHM), a rare autosomal dominant disease [6]. A 24-year-old male was referred with a 1-year history of progressive exertional dyspnoea. Since the age of 8 years, he has reported recurrent episodes of hemiplegic migraine associated with muscle weakness and pain. The proband’s mother (II4) (fig. 1) and two of his brothers (III6 and III7) had recurrent hemiplegic migraine with aura. There was no familial history of PAH. On admission, the patient was in New York Heart Association (NYHA) functional class III. His 6-min …