Turner syndrome — formative SAQs

SAQ 1 (10 marks)

A 13-year-old girl is referred for short stature and absent breast development. She is on the first centile for height, with a low posterior hairline, neck webbing, cubitus valgus, and a soft left infraclavicular murmur. Her bone age is delayed. FSH is markedly elevated and oestradiol is low. A peripheral blood karyotype returns 45,X. ^{[2] [1]}

a) Explain the pathophysiology underlying her short stature and skeletal features, naming the specific gene responsible and its chromosomal location. (2 marks) ^[2]

b) Outline the baseline investigations you will arrange now that the karyotype is confirmed, naming the cardiovascular imaging that defines the aortic risk and two further organ systems requiring screening. (3 marks) ^{[1] [8]}

c) Describe the growth-hormone and oestrogen-replacement plan, including the rationale for the timing of each and the approximate adult-height gain expected from growth hormone. (3 marks) ^{[3] [1]}

d) Explain why the aortic dissection surveillance thresholds are lower in Turner syndrome than in the general population, and name two clinical features that heighten the dissection risk. (2 marks) ^{[1] [8]}