FFinalistSouthampton · 2027
Child health
AKT · Child health/Genetic syndromes

Down syndrome

Trisomy 21

Overview

The commonest autosomal trisomy (trisomy 21), usually from meiotic non-disjunction (risk rises with maternal age). Characteristic facies, hypotonia, learning disability and multisystem associations.

Recognise

  • Facies: epicanthic folds, upslanting palpebral fissures, flat nasal bridge, protruding tongue, single palmar crease, Brushfield spots
  • Hypotonia; learning disability; short stature
  • Sandal gap, brachycephaly

Red flags

  • Congenital heart disease (~50% — AVSD), duodenal atresia, Hirschsprung; later — leukaemia, hypothyroidism, atlantoaxial instability, early Alzheimer

Differentials & how to tell them apart

Other trisomies (Edwards 18, Patau 13)more severe, different features; karyotype
Congenital hypothyroidismcoarse features but normal karyotype, TFTs
Zellweger/other dysmorphic syndromesdistinct features, genetics

Investigations

Antenatal: combined test (nuchal translucency + βhCG↑ + PAPP-A↓) → NIPT/karyotype. Postnatal karyotype confirms. Echo, TFTs, regular surveillance.

Management

  1. 1MDT care: confirm karyotype, echocardiogram (AVSD), screen TFTs, hearing, vision; developmental support.
  2. 2Lifelong surveillance: thyroid, vision/hearing, atlantoaxial, haematological (transient leukaemia/ALL/AML), early dementia.
No drug treats the syndrome — MDT surveillance; treat associations (e.g. levothyroxine for hypothyroidism)

Key points

Associations are the high-yield part: AVSD, duodenal atresia ("double bubble"), Hirschsprung, hypothyroidism, leukaemia, atlantoaxial instability, early Alzheimer.

Monitor & prognosis

Cardiac, thyroid, vision/hearing, growth, development across life.

Improving life expectancy; depends on cardiac and other associations.

Source: NICE; clinical genetics