Inheritance and disease

Question 1

What are the different types of disease?

Answer 1

Non-traditional- mitochondrial
- imprinting
- mosaicism
Mendelian- autosomal recessive
- autosomal dominant
- X- Linked
Chromosomal

Question 2

Explain non-trad disease?

Answer 2

Mitochondrial- all mitochondrial inherited mum
Imprinting- one allele active, other inactive
Mosaicism- error cell division
- same cells have diff genetic
makeup

Question 3

Explain mendelian disease?
Dom/recc
Chance of disease/carrier
M and F?
Generational?
Example?

X linked

Answer 3

Autosomal recessive-homozygous
-require 2 defected genes
- have disease- 25%
- chance carrier- 50%
- chance affected child’s
sibling being carrier-
66.6%
- M and F equally affected
- Affect- single generation
- E.g. Cystic fibrosis

Autosomal dominant- heterozygous
- require 1 defected gene
- chance offspring- 50%
- M and F equally affected
- Multiple generations
- Both parents sometimes
both unaffected (why)
- E.g. Huntingtons

X-Linked- caused mutation X chromosome
- never male to male- sons always X
chromosome from mother
- all daughters from affected males are
carriers
- transmission through unaffected
female
- recessive or dominant
- E.g.Duchennes muscular dystrophy (r)
- Alport’s syndrome (d)

Question 4

In autosomal dominant diseases how can both parents be unaffected?

Answer 4

Gonadal mosaicism (don’t have genes)
Mother reduced penetrance
Mother has variable expression

Question 5

In X-Linked disease why is there no male-male transmission?

Answer 5

Sons always inherit X chromosome from mother

Question 6

What disease class does this show?

Answer 6

Autosomal dominant
Can’t skip

Question 7

What disease class does this show?

Answer 7

Autosomal recessive
Hidden 17

Question 8

What disease class does this show?

Answer 8

X linked recessive

Question 9

What disease class does this show?

Answer 9

X linked dominant

Question 10

Genetic tree diagram q 5x

Answer 10

5x

Question 11

Identify?

Answer 11

Question 12

Identify

Answer 12

Question 13

Identify

Answer 13

Question 14

Explain chromosomal disease?

Answer 14

Numerical or structural
Location determines behaviour during mitosis

Question 15

Define homozygous?

Answer 15

Identical alleles of gene present on both homologous chromosome

Question 16

Define heterozygous?

Answer 16

Cells contain two different alleles of gene
One wild
One mutant

Question 17

What is a wild allele?

Answer 17

Encodes phenotype most common in natural population

Question 18

What disease class is haemophilia?

Answer 18

X-linked recessive

Question 19

Punnet sq X linked dominant

Answer 19

Question 20

Punnet sq X linked recessive

Answer 20

Question 21

Draw diagram:
Affected
Dead
Male
Female
Still born sex unknown
Miscarriage
Termination
Identical twins
Twins
Sex unknown, not born yet

Answer 21

Question 22

State the disease class?

Answer 22

Autosomal dominant

Question 23

State the disease class?

Answer 23

X-Linked dominant

Question 24

State the disease class?

Answer 24

X-Linked recessive

Question 25

State the disease class?

Answer 25

Autosomal recessive

Question 26

State the disease class?

Answer 26

Mitochondrial
Men dont pass so even if affected no pass down
Female pass down

Question 27

State 3 causes of disease?

Answer 27

Genetic
Multifactorial
Environmental

Question 28

Explain genetic and examples?

Answer 28

Individually rare
E.g. Downs, CF, Huntingtons, Haemophilia

Question 29

Explain multifactorial and examples?

Answer 29

Combination genetic and environmental
Main cause disease in dev. countries
E.g. Spina bifida, cleft palate, diab, schiz

Question 30

What is the main cause of disease in developing countries?

Answer 30

Multifactorial
E.g. Spina bifida, cleft palate, diab, schiz

Question 31

Explain environmental and examples?

Answer 31

Main cause of disease in 3rd world
E.g. Poor diet, infection, drugs, accident