Late presentation of Noonan syndrome as atrial flutter in an adult

Abstract

Noonan syndrome is a rare genetic disease with multisystemic manifestations, typically diagnosed in infancy and childhood. This case report presents a 53-year-old woman with no significant medical history who presented with shortness of breath and was subsequently diagnosed with Noonan syndrome. The patient exhibited characteristic facial dysmorphology, including a narrow face, low set ears, and pectus excavatum. Physical examination revealed a crescendo-decrescendo ejection murmur and bilateral lower limb edema. Atrial flutter with rapid ventricular response was detected, and further investigations revealed a large secundum atrial septal defect (ASD) and other cardiac abnormalities consistent with Noonan syndrome. The patient was transferred to a tertiary center for evaluation and management by adult congenital disease specialists. This case highlights the atypical presentation of Noonan syndrome in adulthood and emphasizes the importance of recognizing this condition in patients with cardiac anomalies, as it can impact perioperative management and necessitates genetic counseling. Keywords: Noonan syndrome, genetic disease, multisystemic manifestations, atrial septal defect, adult presentation