Marfan syndrome and heritable connective-tissue disorders — formative SAQs

SAQ 1 (10)

A 14-year-old boy presents with tall stature, a pectus carinatum, a positive wrist-and-thumb sign, and an echocardiogram showing aortic-root dilation at the sinuses of Valsalva. Slit-lamp examination shows superotemporal lens subluxation. There is no relevant family history. ^{[2] [1]}

a) State the diagnosis and the cardinal features that confirm it under the revised Ghent nosology. Explain why a karyotype is not the confirmatory test. (3 marks) ^[2]

b) Explain the two-arm pathophysiology (structural and signalling) and name the molecular discovery that reframed the disease. (3 marks) ^{[3] [1]}

c) Outline the lifelong management plan, naming the medical therapy and the result of the Pediatric Heart Network atenolol-versus-losartan trial. (3 marks) ^{[4] [1]}

d) Both parents are clinically unaffected. State the recurrence risk for the next child and explain the reasoning, including the role of cascade testing. (1 mark) ^{[1] [2]}