inheritance of human disease

Question 1

autosomal inheritance dominant

Answer 1

Only one copy required to cause disease, disease seen in all generations

Question 2

what is the chance of a person affected by an autosomal dominant disorder of passing the mutated gene to each child

Answer 2

50%

Question 3

autosomal inheritance recessive

Answer 3

2 copies of faulty gene required to cause disease, often only 1 generation affected

Question 4

what is the risk of a child being affected by a recessive autosomal inheritance if the parents are carriers

Answer 4

1in 4

Question 5

what is x linked inheritance

Answer 5

Gene fault lies on X chromosome

Question 6

describe an example of x linked inheritance

Answer 6

a female with one pathogenic allele and one normal allele does not show major clinical features of the disease, but a male with a single faulty allele will be fully affected

Question 7

describe mitochondrial inheritance

Answer 7

The mitochondria in the cell have their own genome (single loop)

Question 8

when is a mutation in the mitochondrial genome only present

Answer 8

in a proportion of the mitochondria, and the proportion varies between cells within an individual

Question 9

how is mitochondria DNA transmitted

Answer 9

maternally, in the ovum

Question 10

Haploinsufficiency:

Answer 10

only one copy of working gene, reduced protein production

Question 11

Dominant negative:

Answer 11

expression of abnormal protein interferes with normal protein

Question 12

Gain of function:

Answer 12

mutant protein gains a new function, affecting cell processes

Question 13

Complete loss of function:

Answer 13

autosomal recessive, 2 copies of faulty gene produces no protein

Question 14

what is precision medicine

Answer 14

• Use some form of testing (genetic testing, understanding molecular pathways) to identify a subgroup of patients who respond to treatment
• Most effective for rare diseases and high penetrance mutations