T2 L24 Congenital abnormalities and teratology Flashcards
What is a congenital anomaly?
Abnormality of structure, function or disorder of metabolism that is present at birth and results in a physical or mental disability
What is congenital anomaly also known as?
Birth defects
Clinical dysmorphologies
Congenital malformation
What is teratology?
Study of causes and biological processes leading to abnormal development at fundamental and clinical level and appropriate measures for prevention.
What is incidence?
Number of new cases in a given population over a specific time period
What is birth prevalence?
Fetal loss, stillbirth, TOPs and births per 10,000 births
What is a syndrome?
Multiple congenital abnormalities due to a single aetiology
Example is Down’s syndrome
What is a sequence?
Multiple congenital abnormalities but as a consequence of one abnormality
Example is Potters sequence where you get renal agenesis leading to oligohydramnios leading to skeletal deformities.
How many newborns die from congenital anomalies within 4 weeks of birth every year?
303,000
What are the most common types of congenital anomalies?
Heart defects
Neural tube defects
Down’s syndrome
What are some risk factors for congenital anomalies?
Genetic - inherited vs sporadic mutation
Infectious
Teratogens
Socio-economic / demographics
What are some infectious causes of congenital anomalies?
Rubella
Syphilis
Zika
What is consanguinity and its effect on congenital anomalies?
Creating babies within the family
Increases the rare genetic congenital anomalies and nearly doubles the risk for neonatal and childhood death, intellectual disability and other anomalies.
How can we prevent some congenital anomalies?
Vaccination
Adequate intake of folic acid or iodine through fortification of staple foods or supplementation
Appropriate antenatal care
How can genes play a role in congenital anomalies?
Inherited genetic anomaly
Mutations during development
Describe the link between ethnicity and chromosomal abnormalities
Some ethnic communities have a comparatively high prevalence of rare genetic mutations such as cystic fibrosis and haemophilia C
Who should we screen for genetic disorders?
In high risk patients (those with previous recurrent pregnancy loss or family history for a particular problem)
In all patients through UK AN screening programme
What is the rate and chromosomal anomaly for Down’s syndrome?
25.6 per 10,000 chromosomal abnormalities
Trisomy 21
What is the rate and chromosomal anomaly for Edward’s?
7.6 per 10,000 chromosomal abnormalities
Trisomy 18
What is the rate and chromosomal anomaly for Patau’s?
2.2 per 10,000 chromosomal abnormalities
Trisomy 13
What is the rate and chromosomal anomaly for Turner’s?
3.2 per 10,000 chromosomal abnormalities
XO
What is the rate and chromosomal anomaly for Klinefelter’s?
0.4 per 10,000 chromosomal abnormalities
XXY
How can structural abnormalities be classified?
Malformation
Disruption
Deformation
Dysplasia
What is malformation?
Flawed development of a structure or organ
What is disruption?
Alteration of an already formed organ
What is deformation?
Alteration in structure caused by extrinsic pressures
What is dysplasia?
Abnormal organisation of cells or tissues
What are the features for Down’s syndrome?
Facial features Other external features Cardiac defects Duodenal atresia Mild to moderate learning disability
What are the facial features for Down’s syndrome?
Small nose and flat nasal bridge / flat face
Large tongue that may stick out of mouth
Eyes that slant upwards and outwards
Flat back of the head / thickened skin
What are some external features for Down’s syndrome?
Broad hands with short fingers
Single palmar crease
Below-average weight and length at birth
What are the general features in Edwards syndrome?
Facial abnormalities Skeletal abnormalities Congenital heart defects GI abnormalities Urogenital abnormalities Neurological problems Pulmonary hypoplasia
What is the life expectancy in Edwards syndrome?
Usually die within 1st year of life
What are the facial features of Edwards syndrome?
Small, abnormally shaped head
Small jaw and mouth
Low set ears
Cleft lip / palate
What are the skeletal features of Edwards syndrome?
Long fingers that overlap
Underdeveloped thumbs
Clenched fists
What are the GI features of Edwards syndrome?
Omphalocele Oesophageal atresia Trachea-oesophageal fistula Umbilical or inguinal hernia Pyloric stenosis
What are the urogenital abnormalities of Edwards syndrome?
Gonadal dysgenesis Horseshoe kidney Hydronephrosis Cystic kidneys Renal agenesis
What are the neurological problems in Edwards syndrome?
Anencephaly Hydrocephaly Other brain malformations Severe learning disability Seizures
What are the general features of Patau’s syndrome?
Congenital heart defects Facial abnormalities GI abnormalities CNS disorder = holoprosencephaly Abnormally small penis or enlarged clitoris Skeletal abnormalities
What is the life expectancy of those with Patau’s syndrome?
Usually die within days of birth
What are the facial features in Patau’s syndrome?
Cleft lip / palate Abnormally small eye or eyes Absence of 1 or both eyes Reduced distance between the eyes Microcephaly
What are the GI abnormalities in Patau’s syndrome?
Omphalocele
Exomphalos
What are the skeletal abnormalities in Patau’s syndrome?
Extra fingers or toes
Rounded bottom to feet (rocker-bottom feet)
What are teratogens?
An agent such as a virus, drug or radiation that causes malformation of an embryo or foetus
Give examples of teratogens
Warfarin Thalidomide Rubella Pesticides Hyperthermia Radiation Alcohol Androgens
What is the type and effect of warfarin?
Drug
Chondrodysplasia microcephaly
What is the type and effect of thalidomide?
Drug
Limb defects / heart defectss
What is the type and effect of rubella?
Virus
Rubella (deafness)
What is the type and effect of pesticides?
Chemical
Neural tube defects
What is the type and effect of hyperthermia?
Physical agent
Fetal death, neural tube defects
What is the type and effect of radiation?
Chemical
Microcephaly, spina bifida
What is the type and effect of alcohol?
Chemical
FAS (maxillary hypoplasia mental retardation)
What is the type and effect of androgens?
Hormone
Masculinisation of external genitalia
What are the classic facial deformities in fetal alcohol syndrome?
Epicanthal folds Flat nasal bridge Small palpebral fissures Railroad track ears Upturned nose Smooth philtrum Thin upper lip
When are congenital abnormalities detected?
61% detected antenatally 8% detected at birth 6% at 2-4 weeks 18% after first month Some not until adult life
How can congenital abnormalities be detected?
Pre-implantation genetic testing in IVF
Diagnostic in utero tests
AN screening program
Ultrasound scans
What diagnostic tests are done in utero?
Amniocentesis
CVS
When are ultrasound scans done?
11+ weeks
20 weeks
Third trimester
What is the 11+ week scan looking for?
Anencephaly
Major limb defects
What is the combined screening?
Done at 11+ week scan
Nuchal translucency combined with maternal biochemistry
What is the 20 week scan looking for?
Anomaly scan looking at: heart, brain/spine, skeletal, cleft lip, bowel, kidneys, movements
What are scans in the third trimester looking for?
Growth
Organs
Liquor volume
Movements
What is the benefit of detecting congenital abnormalities?
Termination
Treatment - in utero, maternal or post delivery
Time of delivery
Preparation for parents
