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]

SAQ 2 (10)

A seven-year-old boy is referred because he is the tallest in his class. His father is 193 cm and his mother 180 cm. He is well, his development is normal, and his height is on the 99.6th centile with a growth velocity tracking along the centile. His bone age is two years advanced. His teacher reports he is bright but socially awkward, and on examination he has a prominent forehead, a receding hairline, a long narrow face, and large hands and feet. [1] [6]

a) What is the most likely diagnosis, and which gene is responsible? Explain why the advanced bone age and the facial features redirect the child away from the familial-tall-stature label. (3 marks) [1] [8]

b) Outline the further assessment and investigation that this child needs, including the developmental and the genetic work-up. (3 marks) [6] [1]

c) Contrast this child's prognosis and management with that of a child with familial tall stature. (2 marks) [6]

d) A different tall child, aged seven, has precocious puberty. Explain the paradox by which this child is tall now but will be short at final height, and name the intervention that changes the trajectory. (2 marks) [6]