Chromosomal Syndromes Flashcards
Chromosomal abnormality in Patau’s syndrome?
Trisomy 13
Features of Patau’s syndrome?
- Microcephaly
- Micropthalmia
- Cleft lip / palate
- Polydactyl
How to diagnose Patau’s syndrome?
USS analysis in 2nd trimester
Amniocentesis / cffDNA (NIPT)
Quadruple test : Low AFP, Low estriol, Low HCG, high inhibin
what chromosomal abnormality is seen in Edward’s syndrome?
Trisomy 18
Remember it is 18wards
Features seen in Edward’s syndrome?
- Rocker bottom feet
- Overlapping fingers
- Small mouth
- Low set ears
- Intellectual disability
Patau syndrome survival?
80% die in the first month of life
Quadruple test findings for Edward’s syndrome?
Low AFP
Low Oestriol
Low HCG
Normal inhibin
Chromosomal abnormality seen in Down syndrome?
Trisomy 21
Features seen in Down syndrome?
- Face
- Hypotonia + short neck
- Single palmer crease
- Sandal gap feet
- flat occiput
- heart defects
Complications of living with Down syndrome?
Autism spectrum disorder
Cardiac defects - AVSD
Alzheimer’s
Hypothyroidism
Duodenal atresia
Antenatal screening performed for down syndrome?
Combined test : US and bloods = bHCG high, PAPPA low, Nuchal translucency high
Triple test : high bHCG + low AFP, low Oestriol
Quadruple test : Same as triple test + high inhibin
If US, triple and quadruple test indicated high Down syndrome risk what is done next?
NIPT or Diagnostic CVS or amniocentesis
Chromosomal abnormality found in Turner’s syndrome?
One X chromosomes in females:
45, XO
Features seen in Turner’s syndrome?
Short, shield chest, webbed neck
Bicuspid aortic valve = ejection systolic murmur
+ Coarctation of aorta
*risk of aortic dissection due to coarctation of aorta
Elevated FSH and LH + low O2 = hypergonadotrophic hypogonadism = primary amenorrhoea
What chromosomal abnormality is seen in Klienfelters syndrome?
In boys - extra X
47XXY
Features of Klienfelters?
Normal appearance
- Infertility (high FSH, LH, low Test)
- Hypogonadism
- Gynaecomastia
- Tall
Fragile X syndrome chromosomal abnormality?
CGG trinucleotide repeat expansion mutation
FMR1 gene
Features of Fragile X?
Low IQ 20-80
Macrocephaly
Macroorchidism
Large, low set ears
Long thin face
Join laxity
Mitral valve prolapse
What other conditions have a trinuceotide repeat expansion?
Fragile X
Myotonic dystrophy
Huntington disease
What chromosomal abnormality is seen in Noonan’s syndrome?
Mutated RAS/mitogen
Activated protein kinase
Features of Noonan syndrome?
Pectus excavatum
Pulmonary stenosis
Webbed neck
Trident hairline
Which chromosomal abnormality is seen in Prader-Willi / Angelman’s?
Prader willi : lack paternal 15q
Angelman : lack materal 15q
Prader willi syndrome features?
Hypotonia
Hyperphagia
Almond shaped eyes
Obesity in childhood
Epicanthal folds
Features of Angelman syndrome?
Cognitive impairment
Ataxia
Epilepsy
Facial apperance
