ERU-30 Chromosomal Abnormalities Flashcards
Haploid Diploid Monosomy Mosaic Triploid Trisomy
Haploid: A cell having only 1 of each chromosome (23)
Diploid: Having 1 pair of each chromosome (46, normal)
Monosomy: Having only 1 of a specific chromosome (XO)
Triploid: Having 3 times the normal number of chromosomes (69)
Trisomy: Having 3 copies of 1 chromosome (Down)
Anomaly vs syndrome
Anomaly is a structural feature that differs from the norm (agenesis of the corpus callosum).
A syndrome is a group of findings that exist together. (Down syndrome: flat face, transverse palmar crease)
What is included in a triple genetic screen?
hcg
AFP
estriol
What is PUBS?
Percutaneous umbilical cord sampling (aka cordocentesis): Needle placed through maternal abdomen and into umbilical vein to sample fetal blood
What is the most common chromosomal abnormality?
Down Syndrome (Trisomy 21)
Quad screen testing results indicative of Down syndrome:
Elevated hcg and inhibin A.
Decreased afp, estriol, PAPP-A
Sonographic findings of Down syndrome
Absent nasal bone Brachycephaly (round skull shape) clinodactyly (bending of 5th finger toward 4th) duodenal atresia EIF echogenic bowel macroglossia nuchal thickening pericardial effusion sandal gap shortened limbs VSD
Maternal serum screening results suggestive of Edward syndrome (Trisomy 18)
Low everything (afp, estriol, hcg, inhibin A, PAPP-A)
Sonographic findings of Edward Syndrome
Strawberry-shaped skull Agenesis of the corpus callosum choroid plexus cyst hypoplastic cerebellum hydrocephalus micrognathia esophageal atresia spina bifida cardiac defects diaphragmatic hernia clenched fists
Ultrasonographic findings of Patau Syndrome (Trisomy 13)
Microcephaly Holoprosencephaly polydactyly facial anomalies (cleft lip/palate) Cardiac defects, hypoplastic left heart hydronephrosis
Sonographic findings consistent with triploidy (69 chromosomes)
Syndactyly IUGR Renal hypoplasia Dandy-walker malformation (enlarged cisterna magna, dilation of 4th vent) Holoprosencephaly
What maternal serum screen results are consistent with triploidy?
elevated hcg
What condition is often associated with a triploid fetus?
Molar pregnancy
What maternal serum screen results suggest Turner Syndrome
Low everything (afp, estriol, hcg, PAPP-A, inhibin A
What ultrasonographic findings suggest Turner Syndrome?
Cystic hygroma
increased nuchal translucency
renal anomalies (horseshoe kidney, agenesis)
cardiac anomalies (coarctation of the aorta)
hydrops
