Congenital Defects and their Scientific Basis Flashcards
Define “congenital”
Present at birth
Define “anomaly”
A structural deviation from the norm
Define “genotype” and “phenotype”
The genetic constitution of an individual, and the observable manifestations / clinical features of it
Define “malformation”
Primary disturbance of embryogenesis
Define “disruption”
Secondary disturbance due to early influence of external factors
Define “deformation”
Late changes in previously normal structures, generally mechanical effect
What % of live-born infants of congenital anomalies?
3%
State some historical beliefs regarding causation of congenital anomalies
Witchcraft / supernatural
State some conditions common in Ashkenazi Jews
Haemophillia C
Cystic Fibrosis
What is the aetiology of most Secondary anomalies?
Usually external influences i.e. teratogens
Give examples of Congenital Infections which are teratogenic?
TORCH
Syphillis
Give examples of drugs / environmental pollutants / insecticides which are teratogenic?
Vitamin A Pesticides Medication i.e. Thalidomide Alcohol Folate (deficiency)
Give examples of a Metabolic Maternal Disease which is teratogenic?
Diabetes Mellitus
Polytopic field defects occur at what stages of a pregnancy?
2-4 weeks
Monotopic field defects occur at what stage of a pregnancy?
4-8 weeks
Describe the pattern of effects in an embryo with a polytopic or monotropic field defect
Polytopic - scattered pattern of defects
Monotopic - localised defect
Congenital anomalies specifically affecting organogenesis only would occur at what stage of a pregnancy?
9 weeks or later
Give 3 example of a monotopic field defect
Cleft lip/palate
Tracheo-oesophageal fistula
Holoprosencephaly
Give 2 examples of a polytopic field defect
DiGeorge syndrome
Vacterl syndrome
What does VACTERL stand for?
- Vetrebral anomalies
- Anal atresia
- Cardiac anomalies
- Tracheo-eosophageal fistula
- Renal anomalies
- Limb anomalies
Give an example of a congenital anomalies arising from Organogenesis failure
Neural tube defects
Give 2 examples of conditions which is caused by a Disruption during a pregnancy
Amniotic band syndrome
Poland syndrome
What is Poland syndrome and how is it caused?
Absence of Pectoralis muscle due to interruption of Subclavian artery
Caused by maternal cocaine use
Give 2 examples of congenital anomalies caused by Deformations
Talipes (club foot)
Dislocated hip
Give 2 examples of congenital anomalies caused by Sequence issues
Potters sequence / syndrome
Pierre-Robin sequence / syndrome
State the sequence of events lead to Potters syndrome
Renal agenesis
Oligohydroamnios
Pulmonary hypoplasia
Atypical “squashed baby” appearance with limb defects
Define “syndrome”
A set of signs / symptoms that are correlated with each other
State 2 congenital anomaly conditions caused by Single gene defects
- Rubenstein-Taybi syndrome
- Holt-Oram syndrome
Edwards syndrome is Trisomy…?
18
Patau syndrome is Trisomy…?
13
A pregnant women who drinks has an increased risk of their child developing Foetal Alcohol Syndrome. What effects does alcohol have on the pregnancy?
- IUGR
- Learning difficulties
- Dysmorphic features
- Behaviour problems
Give examples of genetic tests which may be performed to diagnose a congenital anomaly
DNA analysis
Cytogenetic testing
FISH
Microdeletion analysis
Pre-natal exposure to Diethylstilbestrol (DES) is linked to what condition?
Clear cell carcinoma of the vagina
Pre-natal exposure to Phenytoin or Carbamazepine is linked to what condition?
Foetal Hydantoin syndrome
