Paediatric genetics 2

Question 1

What is Turners syndrome?

What causes it?

Answer 1

Chromosomal disorder that only affects females

Caused by presence of only one X chromosome or 2 X chromosomes in which the short arm is lost on one of them

Denoted as (45,X) or (45,XO)

Question 2

What are the physical features of Turner’s syndrome?

Answer 2

Short stature

Features of lymphoedema*

Increased carrying angle (of arms)

Sandle gap

Widely spaced nipples

Webbed neck

Low hairline at back

Question 3

What are the features of lymphoedema* seen in patients with Turners syndrome?

Answer 3

Puffy hands & feet (esp neonates)

Cystic hygroma

Webbed neck (nuchal folds)

Question 4

What organ system abnormalities can be present with Turner’s syndrome?

Answer 4

Cardiac:

• bicuspid aortic valve
• coarctation of aorta
• hypertension

Reproductive

• amenorrhoea & infertility

Endocrine

• elevated gonadotrophins
• hypothyroidism

Renal

• horseshoe kidney

MSK

• skeletal abnormalities as mentioned
• osteoporosis

Question 5

Give an overview of the genetic investigations for a learning disability

What does each test show

Answer 5

Microarray (1)

Fragile X (1)

Targetted testing (2)

Trio-based Exome (3)*

*trio-based genome in england

Question 6

What is 22q11 deletion syndrome?

What is the best way to diagnose it?

Answer 6

DiGeorge syndrome (aka 22q11 deletion syndrome)

Primary immunodeficiency syndrome with T cell deficiency and dysfunction (+ other features)

Microarray - will easily identify it

Question 7

What are the clinical features of 22q11 deletion syndrome?

Answer 7

Pneumonic - ‘CATCH 22‘

Cleft palate

Abnormal facies

Thymic hypoplasia _{- causing T cell deficiency/dysfunction}

Cardiac abnormalities

Hypocalcaemia (hypoparathyroidism)

22

Often causes mild learning disabilities as well

At risk of viral & fungal infections