Genetics

Question 1

Explain Down syndrome

Answer 1

Trisomy 21
Mothers express low AFP and high bHCG
Fetal US shows nuchal translucency
Patients characterized by:
Epicanthal folds, simian crease, common AV canal defects, ASD, VSD
ALL, duodenal atresia, celiac disease, Alzheimer’s

Question 2

Explain Edward syndrome

Answer 2

Trisomy 18
Fatal < 1 year of age
MR
Low set ears, short neck, micrognathia, overlapping/clenched fingers, rocker-bottom feet, large occiput
CHDs, renal malformations, limited hip abduction

Question 3

Explain Patau syndrome

Answer 3

Trisomy 13
Fatal < 1 year of age
MR
Microcephaly, microphthalmia, polydactyly, cleft lip/palate
Cardiac defects, renal defects, umbilical hernia

Question 4

Explain Prader-Willi Syndrome

Answer 4

Portion of paternal chromosome 15 is deleted in fetus
Neonatal hypotonia, FTT
Later childhood hyperphagia => obesity
Mild MR, aggressive/psychotic behavior
Short stature, small hands/feet/gonads

Question 5

Explain Angelman Syndrome

Answer 5

Portion of maternal chromosome 15 is deleted in fetus
Inappropriate laughter => happy puppet syndrome
Jerky, flexed movements
Microcephaly, minimal speech
Severe MR and seizures
Sleep disturbances