Chromosomal Anomalies

Question 0

Chromosome

Answer 0

Centromere: connecting part
Short arm/ P: top
Long arm/ Q: bottom

Question 1

Mosaicism

Answer 1

normal and abnl set of chromosomes

Could be in fetus or in placental cells.

Question 2

Translocation

Answer 2

Balanced: rearranged but no info lost
Unbalanced: loss of genetic info

Question 3

subtle findings

Answer 3

Nuchal Lucency > or = 3 mm
Absent nasal bone
Echogenic intracardiac foci 
Echogenic bowel
Pyelectasis > 4mm

Question 4

Trisomy 21 / Downs Syndrome

Answer 4

Moderately retarded. 20% die in 1st yr bc of ❤️anomalies.

*Inc NF
*NB absent
*Duodenal Atresia (double bubble sign)
*CHD 50%
*AV canal defect
*Absent middle 5th phalanx
*Sandal gap appearance
Hydrops
Short upper extremities
VSD, ASD
Widely spaced toes
*Tetralogy of Fallot: (overriding aorta, vsd, pulmonary artery atresia, right vent Hypertrophy)

EIF
Clinodactyly
Echogenic Bowel
Pyelectasis 
Small ears
Bradycephaly round head

Question 5

Trisomy 13 / Patau Syndrome

Answer 5

Profoundly retarded, 85% die 1st yr

• CHD 90%: (EIF, ASD, VSD, dextrocardia)
• CNS 70%

**holoprosencephaly: forebrain fails to develop into 2 hemispheres
ACC, DWM

Craniofacial anomalies: micrognathia, sloping forehead, clefts, microthalmia,
Cleft lip/palate

Renal abnl: PCK, horseshoe kidney, hydro

GI abnl: omphalocele

Extremities abnl: talipes/club foot (foot turned inward), polydactyly, rocker bottom feet (arched), camptodactyly (bent fingers), overlapping digits

IUGR, polyhydramnios, hypotonia,

Question 6

Trisomy 18 / Edwards Syndrome

Answer 6

Severe retard
Lethal, 90% die within a year
CHD 90% (hypo plastic heart, VSD, ASD)
CDH (st above diaphragm)
*persistently clenched hands
*choroid plexus cysts

Renal: hydronephrosis 
GI: omphalocele, cdh, 
Limb: *overlapping digits, talipes, rocker bottom, absent radius/ulna
Facial: dolichocephaly, micrognathia
CNS: strawberry skull, DWM
SUA, IUGR, poly, hypotonia

Question 7

Turners syndrome

Answer 7

45 XO females only, ID gender
* webbed neck
* cystic hygromas 
*coarctation of aorta
Usually miscarry 
Hydrops
Renal
❤️
Nuchal edema

Question 8

Triploidy

Answer 8

Complete extra set of chromosomes
Severe growth retard. Lethal.
*syndactyly fused 3rd/4th digit

IUGR,
Renal: MCDK, hydronephrosis, ambiguous genetalia, oligo, poly
❤️: CHD, cardiomegaly, VSD
CNS: DWM
GI: omphalocele
Facial: cleft lip/palate, hypertelorism, micropthalmia, low set ears, pointed nose,
SUA

Partial mole with triploidy fetus: enlg molar placenta with cystic spaces

Question 9

VACTERL association

Answer 9

Vertebral 
Anal atresia 
Cardiac
Tracheal Esophageal fistula
Renal
Limb