Tricuspid valve calcification in familial pulmonary alveolar microlithiasis: A case report

Pulmonary Alveolar Microlithiasis (PAM) is an uncommon, gradually progressive and eventually fatal hereditary disease that affects young population. Familial cases account for up to 50% of reported cases. There are few described cases of extrapulmonary manifestations of PAM and rare reports of cardiac involvement.

A 45-year-old male patient presented to our center with progressive shortness of breath and dry cough. On physical examination, he was tachypneic and chest examination revealed diminished breath sounds with bilateral early inspiratory crackles. Further workup revealed the diagnosis of PAM. Echocardiography revealed calcifications covering the tricuspid valve with elevated right ventricular systolic pressure. He reported having two sisters with similar illnesses and chest radiographic abnormalities, one died at the age of 38 years from respiratory failure and the other is 42-year-old and still alive and was diagnosed with PAM. Another 35 member of his family were diagnosed with PAM. Unfortunately, few days after discharge, he arrested at home.

Recently, type-II sodium/phosphate co-transporter has been identified in a human aortic valve. Studies have suggested penetrance of mutations of SLC34A2 gene might explain such variability of pulmonary and extrapulmonary involvement. Our case reports a familial cluster of PAM, and the first case of concomitant tricuspid calcification. This finding might be a useful in the investigation for a future genetic targeted therapy.