Genetics
Most of our DNA is identical [99%}:
- Small number of genes are responsible for our differences.
- Some genes cause disease.- particularly important
- But more commonly genes are one of many factors that interact to cause disease.
- Genetic testing is predictive rather than diagnostic
- Lori B Andrews
o The acquisition and disclosure of genetic info raises new and profound questions about the moral obligations
owed to relatives
o Genetic info influences people's relationships with third parties such as insurers and employers
o People may be afraid to get tested for the disorder because their insurer may drop them entirely or an employer
may refuse to hire them based on their test results
Single gene disorders: - most dramatic form of gene causing disease
1. Dominant autosomal gene: e.g. Huntington’s
o Degenerative
o Incurable
o Will get it if you have the gene- if inherited
o Unusual though- most done work like that
2. Recessive gene e.g. cystic fibrosis- more common
o Need a double RR
o Sickle cell= blood disease
o People don’t know RR- until one carrier has a baby with another
X-linked conditions:- conditions that exist on X chromosome
- X-linked recessive disorder e.g.
o red/green colour blindness
o Haemophilia
o Duchenne muscular dystrophy
→ only affect boys, women can be carriers
- Women have 2 X’s - so if they have it, the other X compensates for it
- Men are XY- won’t have the other X to compensate for the genetic disorder
Susceptibility genes:
- More common
- Increases susceptibility to some conditions
- We all have genes that slightly increase our risk or slightly decreases
- Some rare genes massively increase
o e.g. BRCA1 and BRCA2- increasing risk of breast or ovarian cancer
- If diagnosed?
o Earlier screening programme
o Preventative medication (eg tamoxifen)- to reduce the risk
o Preventative double mastectomy- removing both breasts to remove risk of cancer
What else can be done if diagnosed?
- Most diseases caused by genes - don’t know how to cure most of them. Which is why the info is important.
- Different from diagnoses- predictive- not telling you how to fix, but how to prepare.
- If you find out you have the gene?
- Very sensitive information
- Prevent passing on genes to next generation? [LT]
- Make informed choices about the future?
- Preparing for earlier death?
Who else might be interested in results?
1. Insurers? Probability of serious illness by age 60:
o Average = 15 % [chance of getting sick]
o Adult poly-cystic kidney disease = 75%
o Huntington’s = 100%
In ideal world- insurance companies would want all this information.
But not a good idea; could result in discrimination.
Some people would be uninsurable- means they can’t even get a mortgage.
o HM Government and ABI Code on Genetic Testing and Insurance (2018)
How it works in practice.
Joint code- self denying code that insurance companies won’t require disclosure of tests
Important that you’re truthful to an insurance company- this is one exception to the duty of disclosure
o ‘Insurance industry and government agreement that insurers will not require disclosure of predisposition genetic
tests where the sums insured are: [don’t have to disclose]
UNLESS- Huntingons if you want bigger than those sums:
Less than £500,000 for life insurance
Less than £300,000 for critical illness insurance
Most of our DNA is identical [99%}:
- Small number of genes are responsible for our differences.
- Some genes cause disease.- particularly important
- But more commonly genes are one of many factors that interact to cause disease.
- Genetic testing is predictive rather than diagnostic
- Lori B Andrews
o The acquisition and disclosure of genetic info raises new and profound questions about the moral obligations
owed to relatives
o Genetic info influences people's relationships with third parties such as insurers and employers
o People may be afraid to get tested for the disorder because their insurer may drop them entirely or an employer
may refuse to hire them based on their test results
Single gene disorders: - most dramatic form of gene causing disease
1. Dominant autosomal gene: e.g. Huntington’s
o Degenerative
o Incurable
o Will get it if you have the gene- if inherited
o Unusual though- most done work like that
2. Recessive gene e.g. cystic fibrosis- more common
o Need a double RR
o Sickle cell= blood disease
o People don’t know RR- until one carrier has a baby with another
X-linked conditions:- conditions that exist on X chromosome
- X-linked recessive disorder e.g.
o red/green colour blindness
o Haemophilia
o Duchenne muscular dystrophy
→ only affect boys, women can be carriers
- Women have 2 X’s - so if they have it, the other X compensates for it
- Men are XY- won’t have the other X to compensate for the genetic disorder
Susceptibility genes:
- More common
- Increases susceptibility to some conditions
- We all have genes that slightly increase our risk or slightly decreases
- Some rare genes massively increase
o e.g. BRCA1 and BRCA2- increasing risk of breast or ovarian cancer
- If diagnosed?
o Earlier screening programme
o Preventative medication (eg tamoxifen)- to reduce the risk
o Preventative double mastectomy- removing both breasts to remove risk of cancer
What else can be done if diagnosed?
- Most diseases caused by genes - don’t know how to cure most of them. Which is why the info is important.
- Different from diagnoses- predictive- not telling you how to fix, but how to prepare.
- If you find out you have the gene?
- Very sensitive information
- Prevent passing on genes to next generation? [LT]
- Make informed choices about the future?
- Preparing for earlier death?
Who else might be interested in results?
1. Insurers? Probability of serious illness by age 60:
o Average = 15 % [chance of getting sick]
o Adult poly-cystic kidney disease = 75%
o Huntington’s = 100%
In ideal world- insurance companies would want all this information.
But not a good idea; could result in discrimination.
Some people would be uninsurable- means they can’t even get a mortgage.
o HM Government and ABI Code on Genetic Testing and Insurance (2018)
How it works in practice.
Joint code- self denying code that insurance companies won’t require disclosure of tests
Important that you’re truthful to an insurance company- this is one exception to the duty of disclosure
o ‘Insurance industry and government agreement that insurers will not require disclosure of predisposition genetic
tests where the sums insured are: [don’t have to disclose]
UNLESS- Huntingons if you want bigger than those sums:
Less than £500,000 for life insurance
Less than £300,000 for critical illness insurance
