Tall stature and overgrowth syndromes — formative SAQs

SAQ 1 (10)

A large-for-gestational-age term infant is reviewed at six weeks of age. The mother notes the baby's tongue seems large and protrudes, and the umbilicus has not healed well. On examination the baby is on the 99.6th centile for weight and length, has a markedly enlarged tongue, a soft umbilical hernia, and the left leg is measurably longer and thicker than the right. ^{[2] [9]}

a) What is the most likely diagnosis, and which molecular test confirms it and defines the tumour-risk subgroup? Give the reasoning. (3 marks) ^[2]

b) Outline the tumour surveillance plan this child must now enter, including the imaging modality, the frequency, the age horizon, and the tumours targeted. (3 marks) ^[9]

c) Describe the neonatal complications that may have required management in the first days of life, naming at least three. (2 marks) ^[2]

d) The parents ask whether their next child will be affected. Outline the principles of the recurrence-risk counselling for this condition. (2 marks) ^[2]