SPOTTERS MEDICINE
DOWN’S SYNDROME
🔹 Definition:
Down’s
Syndrome (Trisomy 21) is a genetic disorder caused by the presence of an
extra copy of chromosome 21, leading to intellectual disability,
dysmorphic features, and multiple organ involvement.
🔹 Genetic Basis:
- Trisomy 21 (95%) – nondisjunction during
meiosis
- Translocation (4%) – extra chromosome 21
attached to another chromosome
- Mosaicism (1%) – some cells normal,
others with trisomy 21
🔹 Risk Factors:
- Advanced maternal age (>35 years)
- Family history of chromosomal
abnormalities
- Previous child with Down’s
syndrome
🔹 Clinical Features:
🔸 Physical Features:
- Flat facial profile
- Upward slanting palpebral
fissures
- Epicanthal folds
- Small nose with flat nasal
bridge
- Protruding tongue
- Single transverse palmar crease
(Simian crease)
- Short neck, hypotonia
- Brushfield spots in iris
- Short stature, wide gap between
1st and 2nd toe
🔸 Neurological/Developmental:
- Global developmental delay
- Intellectual disability (mild to
moderate)
- Speech and motor skill delay
🔹 Associated Conditions:
- Congenital heart defects (e.g., AV septal defect)
- Gastrointestinal anomalies (duodenal atresia,
Hirschsprung’s disease)
- Hypothyroidism
- Hearing and vision impairment
- Increased risk of leukemia
- Early-onset Alzheimer’s
disease
🔹 Diagnosis:
🔸 Prenatal:
- Screening tests:
- First trimester: nuchal
translucency + serum markers
- Second trimester: triple or
quadruple screen
- Confirmatory tests:
- Chorionic villus sampling
- Amniocentesis (karyotyping)
🔸 Postnatal:
- Clinical features + karyotyping of peripheral blood
🔹 Management:
- No cure; multidisciplinary approach
- Early intervention:
physiotherapy, occupational & speech therapy
- Cardiac surgery if needed
- Treat associated conditions
(thyroid, hearing, vision)
- Regular developmental monitoring
- Genetic counseling for family
🔹 Prognosis:
- Life expectancy: ~60 years (with
medical care)
- Functional outcome depends on early
therapy and support
- Risk of social and cognitive
impairment can be minimized with early stimulation
DR.C.GANESAN M.D.
PROFESSOR OF MEDICINE
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