Paeds genetics

Question 1

Down’s Syndrome is caused by

Answer 1

three copies of chromosome 21. It is also called trisomy 21

Question 2

Dysmorphic features of down syndrome

Answer 2

Question 3

Complications of down syndrome

Answer 3

Question 4

Explain antenatal screening of down syndrome

Answer 4

The quadruple test is performed between 14 and 20 weeks gestation. It is identical to the triple test but also includes maternal blood for inhibin-A. A higher inhibin-A indicates a greater risk.

Question 5

Antenatal testing of down syndrome

Answer 5

Question 6

Management of down syndrome

Answer 6

Question 7

Average life expectancy for down syndrome is

Answer 7

The average life expectancy is 60 years

Question 8

There are some routine follow up investigations that are important for children with Down’s syndrome:

Answer 8

Regular thyroid checks (2 yearly)
Echocardiogram to diagnose cardiac defects
Regular audiometry for hearing impairment
Regular eye checks

Question 9

Cystic fibrosis (CF) is an… genetic condition affecting which body parts?

Answer 9

Cystic fibrosis (CF) is an autosomal recessive genetic condition affecting mucus glands

Question 10

CF is caused by…most common mutation is…this gene codes for…

Answer 10

• It is caused by a genetic mutation of the cystic fibrosis transmembrane conductance regulatory gene on chromosome 7.
• many variants of this mutation, most common delta-F508 mutation
• This gene codes for cellular channels, particularly a type of chloride channel.

Question 11

The key consequences of the cystic fibrosis mutation are:

Answer 11

Question 12

both parents are healthy, one sibling has cystic fibrosis and a second child does not have the disease, what is the likelihood of the second child being a carrier?

Answer 12

We know the child doesn’t have the condition, so the answer is two in three.

Question 13

first sign of cystic fibrosis

Answer 13

Question 14

Cystic fibrosis is screened for at birth with the

Answer 14

newborn bloodspot test.

Question 15

If cystic fibrosis is not diagnosed shortly after birth it can present later in childhood with typical signs and symptoms…

Answer 15

recurrent lower respiratory tract infections
failure to thrive or
pancreatitis.

Question 16

symptoms of CF

Answer 16

Question 17

signs of CF

Answer 17

Question 18

Causes of clubbing in children

Answer 18

Question 19

There are three key methods for establishing a CF diagnosis that you should remember for your exams:

Answer 19

Question 20

gold standard for confirming the CF diagnosis

Answer 20

sweat test

Question 21

what does the sweat test test for in CF

Answer 21

chloride concentration

Question 22

The diagnostic chloride concentration for cystic fibrosis is more than

Answer 22

more than 60mmol/l

Question 23

common microbial colonisers in CF: which 2 most important to remember

Answer 23

Question 24

Colonisation with…leads to a significant increase in morbidity and mortality in patients with CF

Answer 24

pseudomonas

Question 25

Pseudomonas colonisation can be treated with

Answer 25

Pseudomonas colonisation can be treated with long term **nebulised antibiotics** such as tobramycin. Oral ciprofloxacin is also used.

Question 26

Patients with cystic fibrosis take long term prophylactic…to prevent…infection

Answer 26

Patients with cystic fibrosis take long term prophylactic flucloxacillin to prevent staph aureus infection

Question 27

management of CF

Answer 27

Question 28

monitoring in CF

Answer 28

Question 29

CF prognosis including potential consequences of CF in the long term

Answer 29

Question 30

An increased risk...are the most serious long-term health problems for women with Turner's syndrome

Answer 30

An increased risk of aortic dilatation and dissection are the most serious long-term health problems for women with Turner's syndrome

Question 31

Turner syndrome definition

Answer 31

Turner syndrome occurs when a female has a single X chromosome, making them 45 XO. The O referrs to an empty space where the other X chromosome should be. Life expectancy is close to normal.

Question 32

Turner syndrome features

Answer 32

Question 33

Turner syndrome associated conditions

Answer 33

Question 34

Turner syndrome management

Answer 34

Question 35

Which cardiac defects are associated with turner syndrome?

Answer 35

- Bicuspid valve - aortic root dilatation and dissection - coarctation of the aorta

Question 36

Patau syndrome key features

Answer 36

Microcephalic, small eyes Cleft lip/palate Polydactyly Scalp lesions extra:rocker bottom feet

Question 37

Patau syndrome definition

Answer 37

trisomy 13

Question 38

Edward syndrome key features

Answer 38

Micrognathia Low-set ears Rocker bottom feet Overlapping of fingers

Question 39

Edward syndrome definition

Answer 39

Trisomy 18

Question 40

Fragile X key features in males and females

Answer 40

black and white picture of asian kid

Question 41

Fragile X definition

Answer 41

Question 42

Fragile X diagnosis

Answer 42

* can be made antenatally by chorionic villus sampling or amniocentesis * analysis of the number of CGG repeats using restriction endonuclease digestion and Southern blot analysis

Question 43

Noonan syndrome definition

Answer 43

* male Turner's', Noonan syndrome is an autosomal dominant condition associated with a normal karyotype. * defect in a gene on chromosome 12

Question 44

Noonan syndrome features

Answer 44

Question 45

Pierre robin syndrome features

Answer 45

* Micrognathia * Posterior displacement of the tongue (may result in upper airway obstruction) * Cleft palate

Question 46

Prader Willi syndrome definition

Answer 46

genetic condition caused by the loss of functional genes on the proximal arm of the **chromosome 15** inherited from the father. This can be due to a deletion of this portion of the chromosome, or when both copies of chromosome 15 are inherited from the mother.

Question 47

Prader Willi syndrome features

Answer 47

Question 48

Prader Willi syndrome management

Answer 48

Question 49

William syndrome features

Answer 49

Starburst eyes (a star-like pattern on the iris) Wide mouth with big smile **Friendly, extrovert personality** Short stature Learning difficulties Transient neonatal hypercalcaemia Supravalvular aortic stenosis

Question 50

William syndrome definition

Answer 50

William syndrome is caused by a **deletion of genetic material on one copy of chromosome 7,** resulting in the person only having a single copy of the genes on this deleted region (on the other chromosome 7). It usually the result of a random deletion around conception, rather than being inherited from an affected parent.

Question 51

Cri du chat syndrome definition

Answer 51

chromosome 5p deletion syndrome

Question 52

Cri du chat syndrome features

Answer 52

* Characteristic cry (hence the name) due to larynx and neurological problems * Feeding difficulties and poor weight gain * Learning difficulties * Microcephaly and micrognathism * Hypertelorism