Developmental delay: global diagnostic approach — viva

Opening (must-hit)

“I will confirm multi-domain delay with corrected age if preterm, gate threats and regression, check hearing and vision, start early intervention today, then plan phenotype-driven or agnostic genetic testing with selective metabolic imaging or EEG only for red flags.” [1] [2] [5]

Branch A — Definition

Examiner: What is GDD?
Candidate: Significant delay in two or more domains in a young child — a clinical pattern, not a final molecular diagnosis. It is related to later intellectual developmental disorder but is not the same label at toddler age. [1]

Branch B — Threats

Examiner: What would make you leave the routine pathway?
Candidate: Regression, seizures or encephalopathy, progressive course, severe abnormal neurology, or safeguarding danger. Those need urgent senior review. [1]

Branch C — Genetics eras

Examiner: Karyotype first?
Candidate: Not for unexplained GDD as default. CMA improved CNV yield over karyotype in the Miller consensus era. Current ACMG/AAP guidance supports exome or genome sequencing as first-tier in most unexplained ID/GDD, with copy-number detection and phenotype exceptions. Local access varies. [2] [3] [4]

Branch D — Consent

Examiner: How do you consent for genomic testing?
Candidate: Plain language on possible pathogenic findings, uncertain variants, implications for relatives, and that therapy still proceeds. Paediatric consent/assent principles apply. [6]

Branch E — Communication barrier

Examiner: Parents have limited English.
Candidate: Professional interpreter for history, consent and safety-netting; do not use the child as interpreter. [7]

Closing synthesis

“Supports today, sensory checks, modern genetics in parallel, selective extra tests for red flags, clear review and safety-net.” [1] [2] [5]