POM GENETICS WORKSHOP Flashcards
What mutation is associated with Marfan syndrome and how does this affect the clinical presentation
Mutation in fibrillin 1 protein prevents microfibrils being assembled correctly which in turns effects the strength of elastic fibres in the ECM of connective tissues . This is dominant negative effect because presence of normal allele doesn’t undo the incorrect assembly of mutant allele.
Clinical presentation is also affected by haploinsufficiency and affect on growth factor TGF-b.
What tissues does Marfan syndrome affect and what is likely cause of death
Occular, Skeletal, skin and cardiac systems.
COD: progression of dilated aorta to disecting aortic aneurism, aortic or mitral valve problems, spontaneous pneumothorax.
What mutation is associated with Phenylketonuria and how does this affect the clinical presentation
Mutation is in gene for phenylalanine hydroxylase enzyme- rendering non functional which leads to a build up of phenylalanine substrate
(musty odour, and a reduction of product tyrosine in people with two mutant alleles.
How is phenylketonuria treated
Requires early diagnosis through newborn screening followed by dietary management with low phenylalanine otherwise irreversible damage.
What is a compound heterozygote
Someone who carries two different mutations that cause phenylketonuria which may have differing severities
How does chromosomal defect in trisomy 21 affect clinical presentation
There is over expression of RNA and proteins, including a critical band area on chromosome 21 which may upset the balance between these proteins needed for normal developmental programmes.
Why does advancing age of parents a risk factor for down syndrome. What is the other risk
Older gametes have greater risk of meiotic division: Reduced molecules of cohesin used to form spindle in meiosis more likely for non disjunction. Having previous child with down syndrome.
In the first and second trimester what are the screens done for down syndrome
1st trimester:
Through nuchal translucency screening at 11-14 weeks for increased collected of fluid behind the neck which indicates increased risk for Downs syndrome combined with blood test
2nd trimester:
Maternal serum screening for hormones and factors for embryonic growth- increased conc = chromosomal risk
What are the characteristics of a a good test for diagnosing sars cov 2. What is this test
Sensitive - to identify the infection as early as possible
Specific - reduce false positive by making specific to sars cov2
Throughput - have to be automated and time efficient to have clinical application.
RT-PCR uses primers that match unique non mutating regions of viral DNA to diagnose disease in patient samples
other helpful tests:
Rapid point of testing tests.
Serology tests for antibody response
Viral carbohydrate tests
Why is sequencing of Sars cov 2 important
- Identifying host animal as a potential reservoir for reinfection
- Confirming travel links by specifying where it has come from
- Identifying transmission patterns
- Estimating affected population size
- Monitoring mutations in primer sites and vaccine targets
