(Non-cancer) Genetic Disorders

Question 1

What is the average age of onset of Huntington’s disease?

Answer 1

30-50yrs

Question 2

What does HD cause?

Answer 2

Progressive chorea, dementia and psychiatric symptoms

Question 3

What inheritance characteristics does HD show?

Answer 3

AD with genetic anticipation

Question 4

What does myotonic dystrophy cause?

Answer 4

Progressive muscle weakness and myotonia (failure to relax) in early adulthood

Question 5

What inheritance characteristics does DM show?

Answer 5

AD with genetic anticipation

Question 6

What inheritance characteristics does cystic fibrosis show?

Answer 6

AR

Question 7

What does CF cause?

Answer 7

Increased thickness of secretions - results in recurrent lung infections and exocrine pancreatic insufficiency

Question 8

What does newborn screening for CF measure in blood?

Answer 8

Immunoreactive trypsin (IRT) level

Question 9

What is inheritance pattern of neurofibromatosis 1 (NF1)?

Answer 9

AD

Question 10

What are some minor manifestations of NF1?

Answer 10

Cafe au lait macules and neurofibromas
Short stature
Macrocephaly
Lisch nodules on sclera

Question 11

What are some serious manifestations of NF1?

Answer 11

Scoliosis
Tibial fractures
Phaeochromocytomas
Sarcomas
Optic pathway gliomas

Question 12

What is inheritance pattern of DMD/BMD?

Answer 12

X-linked recessive

Question 13

Which protein is faulty in DMD/BMD?

Answer 13

Dystrophin - normally forms link between F-actin (intracellularly) and the dystroglycan complex in muscle fibres

Question 14

What will boys with DMD have massively increased levels of in their blood from birth?

Answer 14

Serum creatinine kinase - CK leaks out of damaged muscle fibres into serum

Question 15

Which type of deletion is seen in DMD?

Answer 15

“out-of-frame” deletion - results in earlier age of onset than BMD

Question 16

Which type of deletion is seen in BMD?

Answer 16

“in-frame” deletion - results in later age of onset than DMD

Question 17

What is inheritance pattern of fragile x-syndrome?

Answer 17

X-linked recessive with genetic anticipation

Question 18

Which trisomy is Down syndrome?

Answer 18

Trisomy 21

Question 19

Which trisomy is Edwards syndrome?

Answer 19

Trisomy 18

Question 20

What are characteristics of Edwards syndrome?

Answer 20

Small chin, clenched hands with overlapping fingers
Heart/kidney malformations
Severe learning difficulties (if survive 1yr)

Question 21

What is trisomy 13?

Answer 21

Patau syndrome

Question 22

What is average percentage that survive 1yr?

Answer 22

10%