Down's Syndrome

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Down's Syndrome

• Dr Katie Benner
• VTS 1 in paediatrics

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Definition

• In 1887 Landon-Down described a syndrome of
  physical anomalies and mental handicap
• Was previously known as Mongolism, now known as
  Down's syndrome or trisomy 21
• Commonest of the chromosomal disorders and major
  cause of mental retardation
• Incidence increases with maternal age

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Clinical Features

• Brachcephaly

maximal breadth of the skull in the coronal
plain is more than 80 of the length in the
sagittal plain
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• Short neck
• Epicanthic folds

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• Inward down - mongoloid - slant to the eyes
• Brushfield spots on the iris

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• almond shaped eyes
• small simple ears, which may be low set
• flat nasal bridge

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• protruding tongue, mouth hanging open
• narrow high arched palate

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Associations

• duodenal atresia (10)
• Hirschsprung's disease (3)
• other intestinal atresias
• Up to 40 have congenital heart disease
• atrioventricular canal - the most common
• ventricular septal defect
• patent ductus arteriosus
• atrial septal defect - ostium primum (40)
• tetralogy of Fallot

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Management

• Support for family
• Referral to MDT
• Referral to relevant specialists if complications
  arise

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Prognosis

• 90 live to 5 years
• Remainder die of congenital heart disease,
  Hirschprung's and infection

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Antenatal issues

• All pregnant women should be offered screening
  (but it is their choice to decline)
• From 100 to 200 weeks
• 2 different tests depending on when woman
  presents
• If up to 141 gets triple test hCG, PAPP-A and
  nuchal translucency
• If 142 to 200 gets hCG, AFP, uE3, inhibin A

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Maternal risk
Woman's age (years) Risk as a ratio Risk Below
20 11600 0.067 20 11500 0.066 30 1800 0.125
35 1270 0.37 40 1100 1.0 45 and over 1.50
and greater 2.0