Congenital abnormalities and teratology

Question 1

What are the most common, severe congenital anomalies and what are they caused by?

Answer 1

Heart defects, neural tube defects and Downs syndrome.
about 50% has no known cause, but may be:
genetic - inherited or sporadic mutation
infectious - rubella, syphilis, zika
teratogens - external agents e.g. alcohol
demographics - nutritional or environmental

Question 2

What are the types of chromosomal abnormalities?

Answer 2

Inherited genetic anomaly: consanguinity increases prevalence of rare genetic congenital anomalies, some ethnic communities have a comparatively high prevalence of rare genetic mutations.
Mutations during development: primary chromosomal abnormality.

Question 3

What are the chromosomal anomalies that correspond to the following syndromes:

1. Down’s
2. Edward’s
3. Patau’s
4. Turner’s
5. Klinefelter’s

Answer 3

1. Trisomy 21
2. Trisomy 18
3. Trisomy 13
4. XO
5. XXY

Question 4

What are the features of someone with Down’s syndrome?

Answer 4

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
broad hands with short fingers
single palmar crease
below-average weight and length at birth

Question 5

What are the problems associated with Down’s syndrome?

Answer 5

Cardiac defects, duodenal atresia, mild to moderate learning disability.

Question 6

What are some of the abnormalities associated with Edward’s syndrome?

Answer 6

Facial abnormalities: small, abnormally shaped head, small jaw and mouth, low-set ears, cleft lip/palate.
Skeletal: long fingers that overlap, with underdeveloped thumbs and clenched fists.
Congenital heart defects.
Gastrointestinal: omphalocele, oesophageal atresia, umbilical or inguinal hernia, pyloric stenosis.
Urogenital: gonadal dysgenesis, horseshoe kidney, hydronephrosis, cystic kidneys, renal agenesis.
Neurological problems: anencephaly, hydrocephaly, severe learning disability, seizures.
Pulmonary hypoplasia.
Usually die within first year of life.

Question 7

What are some of the abnormalities associated with Patau’s syndrome?

Answer 7

Congenital heart defects: >80%
Facial abnormalities: cleft lip / palate abnormally small eye/s (microphthalmia) or absence of 1 or both eyes (anophthalmia), reduced distance between eyes (hypotelorism), microcephaly.
Gastrointestinal: omphalocele, exomphalos.
CNS disorder: holoprosencephaly.
Abnormally small penis in boys, enlarged clitoris in girls
Skeletal: extra fingers or toes (polydactyly), ‘rocker-bottom’ feet.
Usually die within days of birth.

Question 8

Give some examples of common types of teratogens and their effects.

Answer 8

Thalidomide - drug - limb defects/heart defects.
Radiation - chemical - microcephaly, spina bifida.
Alcohol - chemical - FAS (maxillary hypoplasia, mental retardation).

Question 9

What are the signs of foetal alcohol syndrome?

Answer 9

epicanthal folds, flat nasal bridge, small palpebral fissures, ‘railroad track’ ears, upturned nose, smooth philtrum, thin upper lip.

Question 10

How are congenital abnormalities detected?

Answer 10

Pre-implantation genetic testing – IVF
Antenatal screening program offered to ALL women - ultrasound scans
Diagnostic in utero tests – amniocentesis, CVS

Question 11

Outline the medical and surgical process of termination of pregnancy

Answer 11

Mifepristone orally stops pregnancy, followed by misoprostol which starts uterine contractions.
Tissue evacuated through cervix using suction curette.