T2 L24:Congenital Abnormality & Teratology Flashcards
what is the field of teratology
Teratology: study of causes and biological processes leading to abnormal development at fundamental and clinical level, and appropriate measures for prevention
what are the most common congenital abnormalities
heart defects,
neural tube defects
Down syndrome
what are the risk factors for congenital abnormalities
Genetic – inherited vs sporadic mutation. NB consanguinuity
Infectious – Rubella, Syphilis, Zika
Teratogens
Socio-economic / demographics - nutritional (eg folatic acid) or environmental factors, age
how can congenital abnormalities be avoided
- Vaccination (Rubella)
- Adequate intake of folic acid or iodine through fortification of staple foods or supplementation
- Appropriate Antenatal care.
what is the importance of consanguinity
-increases the prevalence of rare genetic congenital anomalies and nearly doubles the risk for neonatal and childhood death, intellectual disability and other anomalies.
what is prevalent in some ethnic communities
-Some ethnic communities (such as Ashkenazi Jews or Finns) have a comparatively high prevalence of rare genetic mutations such as Cystic Fibrosis and Haemophilia C.
how do you classify structural abnormalities
Malformation: flawed development of a structure or organ (eg. transposition of the great arteries)
Disruption: alteration of an already formed organ (vascular event eg bowel atresia)
Deformation: alteration in structure caused by extrinsic pressures (mechanical eg talipes due to reduced liquor)
Dysplasia: abnormal organisation of cells
or tissues
what is the difference between a syndrome and a sequence
SYNDROME
Multiple congenital abnormalities
Group of abnormalities due a single aetiology
eg single chromosomal/gene problem
SEQUENCE
Multiple congenital abnormalities but as a consequence of one abnormality
Potters sequence:
renal agenesis leading to
oligohydramnios
leading to skeletal deformities
facial features of downs syndrome
small nose and flat nasal bridge/ flat face
large tongue that may stick outof mouth
eyes that slant upwards and outwards
a flat back of the head / thickened skin
features of Edwards syndrome T18
Facial abnormalities: small, abnormally shaped head, small jaw and mouth, low-set ears, cleft lip/palate
Skeletal abnormalities: long fingers that overlap, with underdeveloped thumbs and clenched fists,
Congenital heart defects: >90%
Gastrointestinal abnormalities: omphalocele, oesophageal atresia ± tracheo-oesophageal fistula, umbilical or inguinal hernia, pyloric stenosis
usually dies within first year of life
features of Pataus syndrome T13
Facial abnormalities: cleft lip / palate abnormally small eye or eyes (microphthalmia) or absence of 1 or both eyes (anophthalmia
Gastrointestinal abnormalities: eg, omphalocele, exomphalos
CNS disorder- holoprosencephaly – single brain
usually dies within days of birth
what are teratogenic agents
an agent, such as a virus, a drug, or radiation, that causes malformation of an embryo or fetus.
look at slide 14 for drug teratogens
How was it
what is FAS
Fetal alcohol syndrome :
- Epicanthal folds
- Flat nasal bridge
- Upturned nose
Thalidomide
– The drug was created in Germany by the Grunenthal Group.
1958 – Licensed for use in the UK – morning sickness
1961 – Australian doctor William McBride wrote to the Lancet, after noticing an increase in deformed babies being born at his hospital to mothers who had taken thalidomide. The drug was withdrawn later that year worldwide
1968 – UK manufacturers Distillers Biochemicals Limited (now Diageo) reach a compensation settlement following a legal battle by the families of those affected
1972 – The Sunday Times publishes a front page lead under the banner Our Thalidomide Children, A Cause for National Shame, part of a long-running campaign for further compensation. Eventually, a total of £28 million is paid out by Diageo during the 1970s
2004 – Thalidomide is made available on a named patient basis
2008 – The drug is approved for the treatment of multiple myeloma by the European Medicines Agency.
2010 – Health Minister Mike O’Brien makes a formal apology to Thalidomide victims, expressing “sincere regret and deep sympathy” on behalf of the Government. But the apology was greeted with mixed response from victims, some describing it as “too little, too late”.
2012 – The inventor of Thalidomide, the Grunenthal Group, releases a statement saying it “regrets” the consequences of the drug.
