X Linked Diseases

Question 1

Describe Hypophosphatemic Rickets

Answer 1

X dominant
Mutation in the PHEX gene (P=phosphate X-Xlinked)
Short
Bone Deformity 
Kidneys cant reabsorb phosphate

Question 2

Describe Fragile X

Answer 2

X-Dominant
Trinucleotide repeat (+200rpts=disease)
Exhibits anticipation
Exhibits Maternal transmission bias

Machroorchidism (big balls)
Large face
Autism

Question 3

You tell your friend you are learning about DMD. Excited, because he’s a dweeb, he says he loves dungeons n dragons. You give yourself a facepalm and then explain to him that DMD is a disease that:

Answer 3

You tell him that he’s 21 and needs to grow up (chromosome 21)

Due to frameshift DELETIONS.

You tell him its like a spell that causes progressive muscle weakness, yet LARGE Calves.

DMD Dudes (x-recessive) use upper extremities to help them stand.

Die from DIALATED cardiomyopathy

Question 4

Explain to your friend how to remember BMD vs DMD

Answer 4

BMD=bad you might die (later onset)
DMD=Damn you Dead (early onset)

B also means you have Bad copy of dystrophin, but not a Dead copy.