Genetics Flashcards
What chromosome is affected in Down syndrome →
chromosome 21
What chromosome is affected in Edwards syndrome →
Chromosome 18
What chromosome is affected in Patau syndrome →
Chromosome 13
What physical finding is associated with Down syndrome (hand) →
Single palmar crease
What are the 5A’s of Down syndrome →
Advanced maternal age, Atresia (duodenal), AV septal defect, Alzheimer disease, AML
What screening markers are ↑ in Down syndrome (2nd trimester) →
hCG, Inhibin A
What screening markers are ↓ in Down syndrome (2nd trimester) →
AFP, Estriol
What GI and cardiac defects are seen in Down syndrome →
Duodenal atresia, atrioventricular septal defect
What genetic mechanisms cause Down syndrome →
Meiotic nondisjunction, Robertsonian translocation, postfertilization mitotic error
What is the common heart defect in Edwards syndrome →
VSD (ventricular septal defect)
What hand and foot findings are seen in Edwards syndrome →
Clenched fists with overlapping fingers, rocker-bottom feet
What facial findings are seen in Patau syndrome →
Cleft lip/palate, microphthalmia, microcephaly
What CNS and limb findings are seen in Patau syndrome →
Polydactyly, cutis aplasia
What is the classic physical finding in Patau syndrome scalp →
Cutis aplasia
What is the typical survival for Edwards and Patau syndromes →
Usually death by age 1
What is the first trimester screen result for Down syndrome →
↓ PAPP-A, ↑ hCG
What is the quad screen result for Down syndrome →
↓ AFP, ↓ Estriol, ↑ hCG, ↑ Inhibin A
