Congenital Defects and their Scientific Basis

Question 1

Define “congenital”

Answer 1

Present at birth

Question 2

Define “anomaly”

Answer 2

A structural deviation from the norm

Question 3

Define “genotype” and “phenotype”

Answer 3

The genetic constitution of an individual, and the observable manifestations / clinical features of it

Question 4

Define “malformation”

Answer 4

Primary disturbance of embryogenesis

Question 5

Define “disruption”

Answer 5

Secondary disturbance due to early influence of external factors

Question 6

Define “deformation”

Answer 6

Late changes in previously normal structures, generally mechanical effect

Question 7

What % of live-born infants of congenital anomalies?

Answer 7

3%

Question 8

State some historical beliefs regarding causation of congenital anomalies

Answer 8

Witchcraft / supernatural

Question 9

State some conditions common in Ashkenazi Jews

Answer 9

Haemophillia C

Cystic Fibrosis

Question 10

What is the aetiology of most Secondary anomalies?

Answer 10

Usually external influences i.e. teratogens

Question 11

Give examples of Congenital Infections which are teratogenic?

Answer 11

TORCH

Syphillis

Question 12

Give examples of drugs / environmental pollutants / insecticides which are teratogenic?

Answer 12

Vitamin A
Pesticides
Medication i.e. Thalidomide
Alcohol
Folate (deficiency)

Question 13

Give examples of a Metabolic Maternal Disease which is teratogenic?

Answer 13

Diabetes Mellitus

Question 14

Polytopic field defects occur at what stages of a pregnancy?

Answer 14

2-4 weeks

Question 15

Monotopic field defects occur at what stage of a pregnancy?

Answer 15

4-8 weeks

Question 16

Describe the pattern of effects in an embryo with a polytopic or monotropic field defect

Answer 16

Polytopic - scattered pattern of defects

Monotopic - localised defect

Question 17

Congenital anomalies specifically affecting organogenesis only would occur at what stage of a pregnancy?

Answer 17

9 weeks or later

Question 18

Give 3 example of a monotopic field defect

Answer 18

Cleft lip/palate
Tracheo-oesophageal fistula
Holoprosencephaly

Question 19

Give 2 examples of a polytopic field defect

Answer 19

DiGeorge syndrome

Vacterl syndrome

Question 20

What does VACTERL stand for?

Answer 20

• Vetrebral anomalies
• Anal atresia
• Cardiac anomalies
• Tracheo-eosophageal fistula
• Renal anomalies
• Limb anomalies

Question 21

Give an example of a congenital anomalies arising from Organogenesis failure

Answer 21

Neural tube defects

Question 22

Give 2 examples of conditions which is caused by a Disruption during a pregnancy

Answer 22

Amniotic band syndrome

Poland syndrome

Question 23

What is Poland syndrome and how is it caused?

Answer 23

Absence of Pectoralis muscle due to interruption of Subclavian artery

Caused by maternal cocaine use

Question 24

Give 2 examples of congenital anomalies caused by Deformations

Answer 24

Talipes (club foot)

Dislocated hip

Question 25

Give 2 examples of congenital anomalies caused by Sequence issues

Answer 25

Potters sequence / syndrome

Pierre-Robin sequence / syndrome

Question 26

State the sequence of events lead to Potters syndrome

Answer 26

Renal agenesis
Oligohydroamnios
Pulmonary hypoplasia
Atypical “squashed baby” appearance with limb defects

Question 27

Define “syndrome”

Answer 27

A set of signs / symptoms that are correlated with each other

Question 28

State 2 congenital anomaly conditions caused by Single gene defects

Answer 28

• Rubenstein-Taybi syndrome

- Holt-Oram syndrome

Question 29

Edwards syndrome is Trisomy…?

Answer 29

18

Question 30

Patau syndrome is Trisomy…?

Answer 30

13

Question 31

A pregnant women who drinks has an increased risk of their child developing Foetal Alcohol Syndrome. What effects does alcohol have on the pregnancy?

Answer 31

• IUGR
• Learning difficulties
• Dysmorphic features
• Behaviour problems

Question 32

Give examples of genetic tests which may be performed to diagnose a congenital anomaly

Answer 32

DNA analysis
Cytogenetic testing
FISH
Microdeletion analysis

Question 33

Pre-natal exposure to Diethylstilbestrol (DES) is linked to what condition?

Answer 33

Clear cell carcinoma of the vagina

Question 34

Pre-natal exposure to Phenytoin or Carbamazepine is linked to what condition?

Answer 34

Foetal Hydantoin syndrome