G4- Genetic diseases Flashcards Preview

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Flashcards in G4- Genetic diseases Deck (19)
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1

what is the human genome project?

-The blueprint for the human body and all it’s biological, biochemical and psychological functions
- The sequence of the chemical bases (A, T, C and G) in the DNA on the 24 different human chromosomes

2

what are Qualitative traits?

ABO blood antigens

3

what are quantitative traits?

height, weight or tooth size

4

Describe the modes of inheritance.

-Paired chromosomes (22) plus sex chromosomes
- Gene pairs at same locus (alleles)

5

Describe autosomal dominant.

-When disease mutations are passed down , anyone who inherits these gene will be affected
-Disease seen in all generations
-50% risk of affected child if parent is affected
-Disease severity can be variable
(individuals with a mutation may not show disease) Males and females equally likely to be affected

6

what is crouton syndrome?

skull bones fuse prematurely and restrict brain

7

what is Van Der wood syndrome?

-cleft lip or palate
-lower lip pits

8

what is penetrance?

probability that presence of disease genotype will cause disease

9

what is expressivity?

Variation in the severity of expression of a particular gene

10

Describe autosomal recessive.

-if one copy is transmitted- it will not tramit the disease iself,
-it needs two faulty copies of gene to cause disease
- Often only one generation affected
-1 in 4 risk of an affected child if parents carriers
-Increased likelihood in consanguineous families

11

what increases risk of recessive conditions?

consanguinity (incest)- same gene pool so increases risk

12

Name an example of a recessive condition.

cystic fibrosis

13

Describe X linked recessive inheritance.

-Gene fault lies on the X chromosome
-A female carries a mutation but will not show major features of disease
• For a female carrier
– Half of the male children of a carrier will be affected – Half of the female children will be carriers
• If an affected male has children
– All of male children will be normal (no male to male transmission)
– All of female children will be carriers

14

describe X inactivation.

In Female Cells only One X chromosome is active

15

Describe X-linked phenotype.

-Heterozygous female may show features of the condition
• X-chromosome with mutant allele remains active in some cells (disease)
• In those with normal allele - no disease manifestation

16

Describe multifactoral disorders.

-Spectrum of genetic disease
• Relative genetic and environmental contribution
• Multifactorial threshold model

17

Is there any association between socio-economic status and prevalence of disease?

in deprived areas there is more environmental factors: smoking, drinking , illness that increase risk of disease

18

what is a way of preventing disease?

dietary supplementation

19

Describe pharmacogenetics.

-Individual variation in the capacity to metabolise and use effectively particular compounds
• Characterisation of patients before therapy - improved response rate
• Targeted therapy - improved cost- effectiveness