Dysmorphology examination and syndrome recognition — formative SAQs

SAQ 1 (10 marks)

A term newborn is referred for a detailed assessment after the midwife notes an unusual face and a heart murmur. [1]

1. Outline your structured dysmorphology examination and documentation. (4) [1] [3]
2. Define a major versus a minor anomaly, and explain the significance of finding three or more minor anomalies. (3) [3] [5]
3. State your first-tier genetic investigation and your next step if it is negative. (3) [7] [9] [10]

Model answer

Observe the undressed, settled child first, then examine systematically head to toe — skull and face, neck and chest, abdomen and genitalia, spine, limbs, skin and neurology — describing each finding in standard Elements of morphology terms and avoiding vague language. [1] [3] Measure occipitofrontal circumference and the facial distances against norms, take standardised photographs with consent, and examine the parents. [1] A major anomaly has a structural, medical or surgical consequence; a minor anomaly does not on its own; three or more minor anomalies meaningfully raises the probability of an underlying syndrome and demands a search. [3] [5] First-tier testing is chromosomal microarray; if it is negative and a monogenic syndrome is likely, escalate to exome or genome sequencing, while organising the organ-targeted work-up (for example echocardiography) the pattern demands. [7] [9] [10]

SAQ 2 (10 marks)

Compare the Elements of morphology mechanism categories and outline how they change counselling. [3]

1. Define malformation, disruption, deformation and dysplasia with one example of each. (6) [3]
2. Explain how mechanism and timing alter prognosis, recurrence-risk discussion and what else you examine for. (4) [3] [5]

Model answer

A malformation is intrinsic poor tissue formation during organogenesis (e.g. cleft palate, congenital heart defect); a disruption is extrinsic destruction of normally formed tissue (e.g. amniotic-band limb defect); a deformation is mechanical moulding of normal tissue, often late and often reversible (e.g. positional clubfoot from oligohydramnios); a dysplasia is abnormal organisation of cells in a tissue (e.g. achondroplasia). [3] Mechanism and timing matter because a deformation may resolve once the cause is removed (better prognosis, lower recurrence risk), whereas a malformation is fixed and a dysplasia may progress; a disruption or deformation in one region should still prompt a search for malformations elsewhere, and the recurrence-risk discussion differs for a multifactorial malformation versus a monogenic cause. [3] [5]