Dysmorphia

Question 1

How many live births are T21 babies?

Answer 1

1 in 650

Question 2

How is Down syndrome screened for in the antenatal period?

Answer 2

COMBINED SCREENING: Nuchal translucency and bloods at the 12 week scan
Is given a ‘high-risk’ or ‘low risk’ result. If high risk is offered amniocentesis or CVS

Question 3

What are some characteristic features of Down Syndrome?

Answer 3

Round face and flat nasal bridge 
Upslanted palpebral fissures 
Epicanthic folds 
Brushfield spots in the eye 
Small mouth and protruding tongue 
Small ears 
Flat occiput and third fontanelle 
Short neck 
Single palmar crease 
Sandal gap 
Hypotonia 
Congenital heart defects (AVSD)
Hirschsprung's disease

Question 4

What sorts of things should you cover when counselling a parent with a child with T21?

Answer 4

• 85% children make it past 1st year of life, 505 now live to 50 years and beyond
• Down syndrome is on a spectrum, some are more severely affected than others. We will have to wait and see how affected your child is
• In the first instance it is important to rule our cardiac abnormalities - key life-threatening abnormality
• Forewarn about later medical problems

Question 5

What are some of the later medical problems associated with T21?

Answer 5

Delayed motor milestones due to hypotonia
Moderate to severe learning difficulties
Small stature
Increased susceptibility to infection
Hearing and visual impairment (secretory otitis media, cataracts)
Increased risk of malignancy
Risk of atlanta-axial instability
Increased risk of hypothyroid and coeliac
Epilepsy
Alzheimer’s disease

Question 6

What is the risk of recurrence of Down Syndrome?

Answer 6

1 in 200 if <35yo
Mother of 40 has 1 in 100 chance
Mother of 45 has 1 in 50 chance

Question 7

What genetic abnormality causes CF what are some early features?

Answer 7

Fdelta508 mutation on chromosome 7
Tested for in the Guthrie card test - immunoreactive trypsinogen
Failure to pass meconium can occur
Sweat test can be done to confirm
Also problems with absorption might lead to failure to thrive
RESP FEATURES: dyspnoea, recurrent infections, hyperinflation, coarse inspiratory crackles, expiratory wheeze

Question 8

What chloride concentration in the sweat test is diagnostic of CF?

Answer 8

60-125mmol/L

Question 9

How will CF be managed once detected?

Answer 9

Referral to MDT for discussion
Prophylactic abs - fluclox - usually given via PICC line
Physiotherapy given twice a day
Nebulised DNAase and hypertonic saline
Nutritional management - 150% intake of normal - high in fats (NGT feed over night) - feeding via gastrostomy

Question 10

What is the typical picture of a child with William’s syndrome?

Answer 10

A boy with learning difficulties who is extremely friendly and extroverted and comfortable in the company of adults
Also has supra-ventricular aortic stenosis

Question 11

What are some examples of sex-linked conditions?

Answer 11

Fragile X
DMD
Haemophilias

Question 12

What are some examples of autosomal recessive conditions?

Answer 12

Tend to me METABOLIC CONDITIONS
PKU
Haemochromatosis 
Cystic fibrosis 
Exception - inherited ataxias - dominant

Question 13

What are some examples of autosomal dominants conditions?

Answer 13

Tends to be STRUCUTAL conditions

• Familial adenomatous polyposis
• Achondraplasia
• Marfan’s
• Huntington’s disease
• Ehlers-Danlos
• Exception: Gilbert’s and hyperlipidaemia