9th May 2025

A 30-year-old female from a remote village in a developing country presents to her local emergency department, brought in by her father.

A 30-year-old female from a remote village in a developing country presents to her local emergency department, brought in by her father. He explains that she has progressively become bluer around the lips, toes and fingers, which is more marked during exertion. He is also concerned that she has increased lethargy and fatigue but no fever. He states that recently she has been coughing up blood.

On examination, she looks unwell. She is cyanosed, pale, lethargic and has digital clubbing. Her JVP is raised, and she looks oedematous. There is a mid-systolic crescendo-decrescendo murmur on auscultation and crackles to both lung bases. 

Her investigation results are as follows

Based on the above clinical picture, which underlying uncorrected congenital defect has most likely contributed to her clinical picture?

Select the SINGLE most appropriate option from the list below. Select ONE option only.