Introduction
In 2011, mutation of the NT5E gene, that encodes cluster of differentiation (CD) 73, was found to result in specific calcifications in patients with aneurysmal dilatation of arteries as well as joint calcifications. These symptoms were termed calcification of joints and arteries (CALJA).1 Since then, only 14 patients from 7 families have been reported as having CALJA.2-5Patients with CALJA often experience ischemic symptoms in the lower extremities secondary to severely calcified and occluded arteries. CD73 is also known to play a protective role against aortic valve calcification by hydrolyzation of adenosine monophosphate (AMP) to adenosine.6 Although the deletion of the CD73 gene has been reported to cause aortic valve calcification leading to valvular stenosis in animal models,7 there are no reports of patients with CALJA requiring an aortic valve replacement (AVR) for aortic stenosis (AS). We present two extremely rare cases of sisters with identical NT5E gene mutation patterns, both of whom underwent AVR for AS.