Paeds SAQs · genetics-dysmorphology-and-metabolism
22q11.2 deletion syndrome — formative SAQs
Formative SAQs on 22q11.2 deletion syndrome: recognising the multisystem fingerprint that earns a chromosomal microarray, staging every system at diagnosis, deferring live vaccines until T-cell deficiency is excluded, and running an age-based surveillance plan through to adult transition.
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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]
References6ShowHide
- [1]McDonald-McGinn DM, Sullivan KE, Marino B, et al. 22q11.2 deletion syndrome. Nat Rev Dis Primers, 2015.PMID 27189754
- [2]Bassett AS, McDonald-McGinn DM, Devriendt K, et al. Practical guidelines for managing patients with 22q11.2 deletion syndrome. J Pediatr, 2011.PMID 21570089
- [3]Óskarsdóttir S, Boot E, Crowley TB, et al. Updated clinical practice recommendations for managing children with 22q11.2 deletion syndrome. Genet Med, 2023.PMID 36729053
- [8]Cheung EN, George SR, Andrade DM, et al. Neonatal hypocalcemia, neonatal seizures, and intellectual disability in 22q11.2 deletion syndrome. Genet Med, 2014.PMID 23765047
- [9]Crowley B, Ruffner M, McDonald McGinn DM, Sullivan KE. Variable immune deficiency related to deletion size in chromosome 22q11.2 deletion syndrome. Am J Med Genet A, 2018.PMID 29341423
- [12]Cleynen I, Engchuan W, Hestand MS, et al. Genetic contributors to risk of schizophrenia in the presence of a 22q11.2 deletion. Mol Psychiatry, 2021.PMID 32015465