Abstract
BACKGROUND: In patients with Noonan syndrome (NS), cardiac disorders such as pulmonary valve stenosis (PS) or hypertrophic cardiomyopathy (HCM) are common. While some patients can develop heart failure associated with HCM, the long-term outcome of adult patients with NS is reported to be good. Fatal outcomes of heart failure in patients with NS but without HCM are rare. CASE PRESENTATION: We report a 25-year-old Japanese woman diagnosed with NS in adulthood. She exhibited short stature and minor facial dysmorphism and was diagnosed with PS at 1 year of age. After surgical valvuloplasty for PS at 6 years of age, her general condition became stable without specific medical treatment. She discontinued regular medical follow-up for PS. At 21 years of age, she developed acute decompensated heart failure, which was mainly right-sided heart failure due to severe pulmonary regurgitation (PR) and tricuspid regurgitation (TR). There was no evidence of HCM or PS recurrence. On the basis of the history of PS and characteristic physical features including short stature, webbed neck, and hypertelorism, she was clinically diagnosed with NS. At 25 years of age, she developed heart failure of both sides due to PR, TR and late-onset severe mitral stenosis (MS). The etiology of MS was uncertain. Owing to the patient's condition, surgical options were considered to be extremely high risk. She was treated with optimal medical treatment as well as the occasional abdominal cavity drainage for recurrent ascites; however, she died of decompensated heart failure at 27 years of age. CONCLUSIONS: We describe an adult patient with NS without HCM who died of heart failure caused by severe PR, TR and MS. Clinicians should recognize that ongoing or late-onset cardiac disorders can develop in patients with NS, and lead to fatal heart failure. Optimal medical follow-up to monitor cardiac function and early identification of heart failure are important.