History
Pregnancy/Perinatal: Birth asphyxia, TORCH infections, maternal illnesses, teratogens.
Developmental milestones: Delay or regression?
Family history: Consanguinity, intellectual disability, neurodegenerative disorders.
Associated symptoms: Seizures, hypotonia, dysmorphic features, vision/hearing issues.
Examination
Growth Parameters:
Microcephaly/macrocephaly (indicates brain development issues).
Neurological Features:
Hypotonia, hypertonia, spasticity, hyperreflexia.
Neurocutaneous Stigmata:
Café-au-lait spots (NF1), hypopigmented macules (TSC).
Dysmorphic Features:
Suggest genetic syndromes.
Hearing and Vision:
Audiometry and ophthalmology referral if concerns.
Indication for Step 2: If developmental delay is confirmed, proceed with baseline investigations.
These tests identify common and reversible metabolic, endocrine, or genetic causes.
Test
Indication
Possible Diagnoses
Thyroid Function Tests (TSH, Free T4)
Signs of hypothyroidism, poor growth
Congenital hypothyroidism
Complete Blood Count
Anemia, pallor, fatigue
Iron-deficiency anemia
Iron Studies
Delayed milestones, pica
Iron-deficiency anemia
Serum Amino Acids
Unexplained GDD, seizures
Phenylketonuria, urea cycle defects
Urine Organic Acids
Developmental regression, metabolic acidosis
Organic acidurias
Serum Ammonia
Unexplained encephalopathy
Urea cycle disorders
Serum Lactate & Pyruvate
Lactic acidosis, metabolic crisis
Mitochondrial disorders
Indication for Step 3: Abnormalities in baseline results or persistent unexplained delay.
Targeted genetic tests are chosen based on clinical suspicion or family history.
Test
Indication
Possible Diagnoses
Chromosomal Microarray (CMA)
Dysmorphic features, structural anomalies
Chromosomal disorders (e.g., microdeletions, duplications)
Fragile X Testing (FMR1)
Male with autism, family history of ID
Fragile X syndrome
Single-Gene Testing
Suspicion of specific syndromes
Rett syndrome, TSC
Whole Exome Sequencing (WES)
No diagnosis after other tests
Rare genetic syndromes
Indication for Step 4: Abnormalities suggesting brain structure issues, seizures, or neurocutaneous findings.
MRI Brain is the imaging modality of choice for structural abnormalities.
Finding
Clinical Indication
Possible Diagnoses
Ventriculomegaly, calcifications
Seizures, developmental regression
Congenital infections (CMV, toxoplasmosis)
Hypomyelination
Delayed milestones, hypotonia
Leukodystrophies
Basal ganglia lesions
Regression, lactic acidosis
Mitochondrial disorders (e.g., Leigh syndrome)
Cortical tubers, nodules
Neurocutaneous stigmata (e.g., TSC)
Tuberous sclerosis
TORCH Panel: Suspected congenital infections (hepatosplenomegaly, calcifications).
CSF Analysis: Developmental regression with seizures or encephalopathy (e.g., neurotransmitter disorders).
Skin Biopsy: Suspicion of lysosomal storage diseases or mitochondrial disorders.
Electroencephalogram (EEG): Seizures or suspicion of epileptic encephalopathy.
Condition
Key Features
Key Test
Treatment
Congenital Hypothyroidism
Poor growth, lethargy
TSH, Free T4
Levothyroxine
Phenylketonuria
Delayed milestones, seizures
Plasma phenylalanine
Phenylalanine-restricted diet
Biotinidase Deficiency
Hypotonia, seizures, alopecia
Biotinidase activity
Biotin supplementation
Mitochondrial Disorders
Regression, lactic acidosis
Lactate, MRI
Coenzyme Q10, supportive therapy
Fragile X Syndrome
Male with autism, large head
FMR1 gene testing
Behavioral therapy, educational support
Tuberous Sclerosis
Neurocutaneous stigmata, seizures
MRI, genetic testing
Vigabatrin, mTOR inhibitors
As a parent watching your child develop , this may be both exciting and worrying at times. When your child learns a new activity e.g. walking it is an exciting time. However normal children may develop at different speeds, and when a child is seemingly slow to develop a milestone (E.g. again such as walking), it may be anxiety provoking.
That said, this Red Flags Early Identification for Developmental Delay (Birth to 5 years) lists times in a child's life, if they have not achieved a milestone that this could be considered a "red flag".
That is, if your child has a "red flag" , this could be abnormal and this should be discussed with your community nurse, or your GP, and/ or you could consider a referral to a paediatrician.
If you child has two areas of delay, your child may have global developmental delay, which should be discussed with a health professional.
Below is a list of normal milestones from American CDC list (which has excellent videos of children and their activities) and your
NSW Australian Blue Book.
Read the ages close to your child and note where you child is. It might be higher than average and lower than average in others. If you are concerned about your child's development look at where you child's development is up to, and discuss with a health professional.
Full check list of milestones with one per per age
3 years Blue book at 3 years