L22-23: GENETICS, GENOMES & DISEASE

Question 1

Acrocentric chromosomes include

Answer 1

chromosome 13, 14, 15, 21, 22

Question 2

Robertsonian translocation

Answer 2

Translocation between two acrocentric chromosomes

Question 3

Methods of sampling of fetal cells/DNA/RNA

Answer 3

Chorionic villus sampling (CVS) - inserting needle into the placenta (in the region of the trophoblast) and Amniocentesis - taking sample of amniotic fluid

Question 4

Duchenne muscular dystrophy

Answer 4

Increasing proximal limb muscle weakness due to progressive muscle degeneration.
Caused by mutation(s)/variants in a gene encoding a muscle protein called dystrophin, found in all muscle and brain. Dystrophin forms link between actin (cytoskeleton) and extracellular matrix.

Question 5

Dystrophin function

Answer 5

Acts both as a physical link between the cytoskeleton and the myofibrils, but also involved in some intracellular signalling.

Question 6

Dystrophin-associated protein complex (DAPC) function

Answer 6

1. Stabilises sarcolemma during cycles of contraction and relaxation
2. Transmits force generated in muscles to ECM
3. Involved in cell signalling

Question 7

How are DMD and BMD diagnosed?

Answer 7

1. Creatine kinase (blood) screening test
2. Muscle biopsy
3. DNA tests - direct testing, primarily for deletion; sequencing