Down syndrome explanation

Question 1

What is Down’s syndrome?

Answer 1

• Down’s syndrome is a condition that involves a person’s genes
• Genes contain information that determines everything about a person, from their gender to their hair colour. So you might like to think of a gene as a recipe
• Genes are grouped together into chromosomes. So if a gene is a recipe, then a chromosome is a recipe book.
• Each person has a specific number of chromosomes. In Down’s syndrome however, the child has an extra chromosome. This extra genetic information changes the way their body develops.
• This gives them a unique appearance on the outside, and also a unique appearance on the inside.

Question 2

What problems might a child with Down syndrome have?

Answer 2

• Changes to their development on the inside can lead to certain medical problems
  
  • They may have problems with their heart
  • They may have problems with their digestive system
  • They may have some degree of learning difficulties
• Every child with Down’s syndrome is unique - Some may have very minimal limitations and go on to live independent, healthy lives, while others might require slightly more input from medical staff.
• The important thing to remember is that you will have plenty of support from a range of different health professionals, tailored to suit the needs of your child.

Question 3

Risk factors for Down’s

Answer 3

• Increased maternal age
• Previous child with Down’s

Question 4

Prenatal screening for Down’s

Answer 4

• Screening (NOT diagnostic)
  
  • Blood sample ~11 weeks
    
    • Hormones which may be raised in Down’s
  • Ultrasound ~11 weeks
    
    • Nuchal translucency
• Results are used to calculate the chance of the foetus having Down’s, taking into account maternal factors (age, weight, origin, gestation)
  
  • If >1 in 150 chance, diagnostic testing offered

Question 5

Diagnostic tests for Down’s

Answer 5

*Indications - high risk screening results/maternal age >37*

• Amniocentesis
  
  • ~15 weeks
  • Procedure
    
    • Procedure involves inserting a needle through the abdomen and into the amniotic (pregnancy) sac
    • Needle inserted under ultrasound guidance by expert
    • Mild, short-lived discomfort on insertion
    • 15-20 mls amniotic fluid withdrawn
    • Cells from fluid analysed for chromosomes
    • Ultrasound check of foetal heart afterwards
  • Complications
    
    • Miscarriage 0.5-1%
    • Infection
    • Reassure complications are rare
  • Results
    
    • 2 weeks for full result (cell analysis)
    • 24-48h for preliminary results
    • >99% correct
• Chorionic villous sampling
  
  • 11-13 weeks
  • Procedure
    
    • Fine needle passed through the abdomen and into the womb to take a small sample of the placenta (transabdominal)
    • Sometimes because of the posiiton of the uterus or the placenta, the needle may be passed through the cervix in order to get a sample (transcervical)
    • Ultrasound guidance by expert
    • Minimal discomfort (a bit like period pain/smear), local anaesthetic may be used
    • Ultrasound of foetal heart afterwards
  • Complications
    
    • Miscarriage 1%
    • Infection
    • Reassure complications are rare
  • Results
    
    • 2 weeks for full result (cell analysis)
    • 24-48h for preliminary results
      >99% correct