Down's syndrome

• What is Down's syndrome?


  Genetic disorder

  3 copies of chromosome 21 (trisomy 21)

  Characteristic dysmorphic features
• What are the dysmorphic features of Down's syndrome?


  Hypotonia

  Brachycephaly (small head with flat back)

  Short neck

  Short stature

  Flattened face & nose

  Prominent epicanthic folds (folds of skin covering the medial portion of the eye & eyelid)

  Upward sloping palpebral fissures (gaps between lower & upper eyelid)

  Single palmar crease
• What are the complications of Down's syndrome?


  Learning disability

  Recurrent otitis media

  Deafness

  Eustachian tube abnormalities (can lead to glue ear & conductive hearing loss)

  Visual problems (myopia, strabismus, cataracts)

  Hypothyroidism

  Cardiac defects (esp. ASD, VSD, patent ductus arteriosus & tetralogy of Fallot)

  Atlantoaxial instability

  Leukaemia

  Dementia
• What are the RFs of Down's syndrome?


  Increasing maternal age

  Previous child with Down's syndrome

  Parental karyotype with a translocation
• What are the DDx of Down's syndrome?


  Isolated hypotonia

  Zellweger's syndrome

  Congenital hypothyroidism
• What is the management of Down's syndrome?


  Supportive care from MDT

  • Occupational therapy
  • Speech and language therapy
  • Physiotherapy
  • Dietician
  • Paediatrician
  • GP
  • Health visitors
  • Cardiologist for congenital heart disease
  • ENT specialist for ear problems
  • Audiologist for hearing aids
  • Optician for glasses
  • Social services for social care and benefits
  • Additional support with educational needs
  • Charities such as the Down’s Syndrome Association

  Regular follow ups
• What is involved in the regular follow ups for Down's syndrome?


  Regular thyroid checks (every 2 yrs)

  Echo (to diagnose cardiac defects)

  Regular audiometry

  Regular eye checks
• What is the average life expectancy of a person with Down's syndrome?


  60 yrs
• What is the antenatal screening for Down's syndrome?


  Combined test (1st line)

  Triple test

  Quadruple test
• What is the combined test?


  Performed 11-14 wks gestation

  Combines results from USS & maternal blood tests

  USS

  • measures nuchal translucency
  • over 6 mm -> indicative of Down's syndrome

  Maternal blood tests

  • beta-HCG -> higher result indicates greater risk
  • pregnancy-associated plasma protein-A (PAPPA) -> lower result indicates greater risk
• What is the triple test?


  Performed 14-20 wks gestation

  Maternal blood tests only

  • beta-HCG -> higher indicates greater risk
  • alpha-fetoprotein (AFP) -> lower indicates greater risk
  • serum oestriol -> lower indicates greater risk
• What is the quadruple test?


  Performed 14-20 wks gestation

  Identical to triple test BUT also includes maternal inhibin-A (higher indicates greater risk)
• What happens if there is a positive screening test for Down's syndrome?


  Offered prenatal diagnostic test (risk of miscarriage < 0.5%)

  • Chorionic villus sampling
  • 10-14 wks gestation
  • US guided biopsy of placental tissue
  • Amniocentesis
  • after 15 wks gestation
  • US guided aspiration of amniotic fluid
• What can be done post birth to test for Down's syndrome?


  Genetic testing
• Newborns with Down's syndrome often require screening for complications. What does this include?


  Echo

  Radiographic swallowing assessment (to detect feeding difficulties)

  Red reflex test (detect congenital cataracts)

  TSH & free T4 (screen for thyroid disease)

  FBC (detect transient myeloproliferative disorder or polycythaemia)

  Screening for coeliac disease

  Hearing tests
• What are the signs & symptoms of Down's syndrome?


  Hypotonia & hyperreflexia

  Characteristic facial features

  Single palmar crease

  Short stature

  Learning difficulties

  ENT -> increased susceptibility to otitis media, OSA, hearing loss

  Cardiac -> VSDs, isolated secundum ASDs, Tetralogy of Fallot

  Ophthalmology -> cataracts, refractive errors, strabismus

  Endocrine -> thyroid disease

  GI -> hirschsprung's disease, congenital duodenal or oesophageal atresia, meckel's diverticulum, GORD, coeliac

  Ortho -> scoliosis, hyperflexibility

  Early onset Alzheimers

  Haemotology -> AML, ALL