Medicine & USMLE


Chromosomal Abnormalities
  1. Down Syndrome (Trisomy 21)
  2. Edwards Syndrome (Trisomy 18)
  3. Patau Syndrome (Trisomy 13)
  4. Klinefelter Syndrome
  5. Turner Syndrome
  6. Williams Syndrome
  7. Cri du Chat Syndrome
  8. Imprinting

Imprinting Disorders include Prader-Willi Syndrome and Angelman Syndrome, congenital diseases affecting expression of genes on chromosome 15.

Prader-Willi Syndrome occurs when the maternal gene is imprinted (and hence silent) and the paternal gene is mutated/deleted. Prader-Willi Syndrome classically presents with hyperphagia and hypoplastic/undescended testicles.

Angelman Syndrome occurs when the paternal gene is imprinted and the maternal gene is mutated/deleted, and presents with inappropriate laughter ("happy puppet syndrome") and severe cognitive disability.

Find Prader-Willi, Angelman Syndrome, and more Chromosomal Abnormalities among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.