22q11.2 deletion syndrome — formative SAQs

SAQ 1 (10)

A term neonate is transferred to the neonatal unit at twenty-four hours of age with respiratory distress and a mottled appearance. Examination reveals a systolic murmur, weak femoral pulses, a bulbous nasal tip and small ears, and a cleft of the soft palate. A corrected calcium returns at 1.5 mmol per litre. A standard karyotype has been reported as normal. [1] [2]

a) What is the most likely unifying diagnosis, and which investigation — that has not yet been performed — will confirm it? Explain why the test already done was inadequate. (3 marks) [1]

b) Outline the full systems-staging work-up that should be performed at diagnosis, naming at least six components and the specific harm each prevents. (3 marks) [2] [3]

c) State the immediate management of the hypocalcaemia, including the acute and the maintenance approach. (2 marks) [8]

d) The family asks about the rotavirus and BCG vaccines due on the schedule. State the principle that governs live vaccines in this child, and how the schedule is cleared. (2 marks) [9]

SAQ 2 (10)

A fifteen-year-old girl with a repaired tetralogy of Fallot and a previously unexplained history of nasal speech and recurrent otitis media in early childhood presents with declining school performance, new anxiety, and fatigue. Her thyroid function has not been checked in five years. She was diagnosed clinically in infancy; no molecular confirmation is recorded. [1] [12]

a) What is the most likely underlying diagnosis, and what is the appropriate confirmatory test? Give the reasoning. (3 marks) [1] [2]

b) Outline the adolescent surveillance that this girl should now receive, naming at least five systems including the psychiatric and endocrine surveillance. (3 marks) [3] [12]

c) Explain the significance of the schizophrenia-spectrum risk in this condition, quantifying it, and describe the surveillance and early-intervention approach. (2 marks) [12]

d) The girl's mother is found to carry the same deletion, having been unaware of it. State the recurrence risk for future pregnancies and the implications for the wider family. (2 marks) [1]