Dysmorphology examination — branching viva

Opening stem

You are the paediatric registrar in clinical genetics clinic. A 6-month-old is referred for an unusual face and developmental delay. Talk me through your assessment. [1]

Branch A — Candidate opens with structured examination

Examiner: Good. How do you describe the findings, and why does the vocabulary matter? [1]

Strong answer: Observe the settled, undressed child first, then examine head to toe, describing each feature in standard Elements of morphology terms and measuring against norms. Standard terminology makes findings reproducible between clinicians and over time, and avoids vague labels. I photograph with consent and examine the parents. [1]

Branch B — Classification of anomalies

Examiner: How do you classify what you find? [3]

Strong answer: Two axes — mechanism (malformation, disruption, deformation, dysplasia, with an example of each) and significance (major versus minor). A cluster of three or more minor anomalies substantially raises the probability of a syndrome and prompts a structured search. [3] [5]

Branch C — Generating the differential

Examiner: How do you narrow the differential from here? [5]

Strong answer: Group the truly abnormal findings (using measurements and parental examination to strip out familial or ethnic variants) into a pattern, then compare against databases (London Dysmorphology Database, OMIM, Human Phenotype Ontology) and a deep-learning facial-analysis tool as support. A tool match never replaces clinical judgement or genetic confirmation. [5] [12]

Branch D — First-tier testing

Examiner: What is your first genetic test, and why? [9]

Strong answer: Chromosomal microarray is first-tier for unexplained developmental delay and multiple congenital anomalies because it detects submicroscopic copy-number changes a karyotype misses, with a yield of roughly 10 to 15 percent; a karyotype is reserved for a suspected balanced rearrangement. [9]

Branch E — Negative microarray

Examiner: The microarray is negative and you still suspect a monogenic syndrome. Now what? [10]

Strong answer: Escalate to exome or genome sequencing, which adds a substantial diagnostic increment; I also organise the organ-targeted work-up the pattern demands and arrange genetic counselling and a clear review point for the family. [7] [10]

Closing marks map

• Structured, terminology-driven examination with measurements and parental examination. [1]
• Correct two-axis classification and the three-or-more-minor-anomalies rule. [3] [5]
• CMA as first-tier, then exome or genome, with honest counselling and a safety-net review. [9] [10]