Abnormal Child Development + normal/ abnormal growth Flashcards
A 2-year-old child has delays in speech, motor skills, and social interaction. What is the most appropriate term for this pattern of development?
Global developmental delay
A baby is not reaching for objects by 6 months. What is this considered?
Red flag
A child with previously normal development begins losing speech and purposeful hand use. What’s the most likely cause?
Rett syndrome
= Characteristic developmental regression, especially in girls
Which of the following is a prenatal cause of global developmental delay?
A) Hypoxic-ischaemic encephalopathy
B) PKU
C) Meningitis
D) Prematurity
PKU
= It’s a metabolic prenatal cause; A and D are perinatal, C is postnatal
A 4-year-old boy has delayed walking but normal language and social development. What’s this pattern?
Specific delay
Only motor domain affected → think of causes like Duchenne or CP
A child is diagnosed with developmental delay. What’s the first-line genetic investigation?
Oligoarray CGH
Gold standard test for Autism Spectrum Disorder
Autism Diagnostic Observation Schedule
What’s a key feature that distinguishes developmental delay from developmental deviation?
Delay = slower but typical pattern; Deviation = abnormal pattern (e.g. autism)
What measurement should always be plotted in developmental assessment?
Height, weight, and head circumference
A child has motor delay and calf pseudohypertrophy. What test do you order?
Creatine kinase — to screen for Duchenne muscular dystrophy
What is specific Developmental Delay?
Only one domain is affected
(eg) only motor, or only speech/language
Example: A child who has normal play, learning and behaviour but isn’t talking by age 2
Think: Isolated problem, rest of development normal
What is Global Developmental Delay (GDD)?
Two or more domains delayed before age five
(eg) speech + motor, or cognition + social
Example: A child who isn’t walking at 20 months and isn’t speaking at all
Think: Widespread delay in skills
What is Developmental Regression?
Loss of previously acquired skills
Example: A child who used to talk and play normally but stops talking and loses interest in people
Think: They had the skill, but now it’s gone
What is Developmental Deviation?
Atypical development, not just slow
Example: A child who shows repetitive behaviours and doesn’t engage socially (eg, autism)
Think: Unusual pathway, not just behind
If development odd or uneven?
Deviation
When to use oligoarray CGH (comparative genomic hybridisation)?
🧪 First-line test for unexplained developmental delay, intellectual disability, congenital anomalies
Detects microdeletions and duplications (much smaller than karyotyping)
Can’t detect balanced translocations or single-gene disorders
✅ Use when
= child has global delay, dysmorphic features, or unexplained birth defects
When to use Karyotyping?
🧬 Low-resolution chromosome analysis
Detects large chromosomal abnormalities (eg, trisomy 21, Turner’s, translocations)
Slower and less sensitive than CGH
✅ Use when
= you suspect known syndromes with visible changes (e.g. Down’s, balanced translocations in the family)
When to use Whole genome sequencing (WGS)?
📚 Sequences all DNA, including coding and non-coding regions
Can detect single-gene mutations, CNVs, and more
Still used more in research or specialist genetics settings
✅ Use when
= CGH, karyotype, and other tests are normal, but clinical suspicion remains high
When to use FISH (fluorescence in situ hybridisation)?
🔍 Targeted test for a specific microdeletion or rearrangement
Fast and used when you already have a clinical suspicion (eg, DiGeorge, Williams)
✅ Use when
= looking for a known condition, not a screening test
What are the prenatal causes of global developmental delay?
- Down’s syndrome
- PKU, hypothyroidism
- neuronal migration disorders
- TORCH infections
- TOXINS
At what age is pubertal delay diagnosed in boys?
14
What is used as the first-line investigation for a girl with short stature and delayed puberty?
Karyotyping - always rule out Turner’s syndrome
A 6-year-old girl develops breast buds and pubic hair. What is this?
true central precocious puberty if <8 in girls
Which measurement tool is used to assess length in a 1-year-old?
children under 2 should be measured lying down
