Teratology Definitions

Question 1

What is a malformation?

Answer 1

Disturbed formation of a structure resulting in its complete or partial absence or abnormal configuration

Question 2

Give some examples of a malformation

Answer 2

Trachea-oesophageal fistula (w/ or w/out oesophageal atresia)
CLP
Limb defects (complete or partial absence of limb)
VSD, ASD…etc

Question 3

What is a disruption?

Answer 3

Structural alteration, due to a destructive process, of a structure that is already formed (secondary destruction)

Question 4

Give an example of a disruption

Answer 4

Amniotic bands

Question 5

What is a deformation?

Answer 5

Abnormal moulding of part of the fetus by mechanical forces

Question 6

Give some examples of a deformation

Answer 6

Small for gestational age (due to multiple pregnancy or oligohydramnios)

Club foot (oligohydramnios)

Question 7

What is a syndrome?

Answer 7

A group of anomalies that occur together with a common cause

Question 8

Give some examples of syndromes

Answer 8

Downs, turners, Pataus, leader Willi, fragile X, FAS…etc

Question 9

What is an association?

Answer 9

Non-random occurrence of 2 or more anomalies together, but cause is UNKNOWN

Question 10

Give an example of an association

Answer 10

VACTERL

• vertebral defects
• anal atresia
• cardiac defects
• tracheo-esophageal fistula
• renal abnormalities
• limb defects

Question 11

What are the principles of teratology? List the 5

Answer 11

The factors affecting how easily a given agent can cause a congenital defect

1) stage of pregnancy/development (timing)
2) genetics (predisposition of mother/fetus)
3) dose and duration of exposure
4) mechanism of action of the causative teratogen
5 manifestation of the abnormality that has been caused

Question 12

What symptoms and signs and abnormalities is FAS associated with?

Answer 12

• Facial: smooth filtrum, thin upper lip, flattened nasal bridge, epicanthal folds
• Growth restriction
• CHD (VSD!!!)
• Brain/CNS: microcephalic
• behavioural problems (ADHD and autism)
• intellectual disability

Question 13

What author/year wrote the FAS paper?

What does the paper say about how alcohol acts as a teratogen?

Answer 13

Gupta et al (2016)

1. ROS production (by-product of CYP2E1)
2. decreased endogenous antioxidant levels
3. lipid peroxidation
4. disrupted neuronal cell-cell adhesions
5. placental vasoconstriction (hypoxia)
6. Inhibition of co-factors required for fetal growth/division

–> these lead to cellular damage / apoptosis of fetal brain tissue during development