Genetics Tutorial

Husband brings along 55year old lady, tripped on several paving stones in last month, depressed, irritable, twitchy. Not herself. Patient seems guarded and reluctant to accept anything may be wrong. Husband says he’s worried for their 27 year old son, who’s wife is expecting.

Case Study 2:

19 year old girl, blackout 4 times in last 3 months, also gets palpitations. Uncle used to have lots of faints as a child and died playing rugby. Very worried because she likes dancing.

Case Study 3:

27 year old lady sees you clutching a pile of papers, saying 'I've decided to go ahead and have a bilateral mastectomy - can you refer me to a surgeon, but not the one that operated on my sister'

2 Family history - one in ten?

Study in 2004 suggested at least one in ten patients seen in primary care have a disorder with a genetic component.

Single gene disorders - individually rare but many of them - affect up to 5% population.

(Familial hypercholesterolaemia, Marfan's Syndrome, inherited cardiomyopathies and arrhythmias)

25-35% of common cancers (breast, bowel, prostate) have a heritable component.

Identifiable genes related to breast, ovarian and colon Ca increase the workload of clinical genetics departments, 40% of referrals come from GPs.

BRCA1 and BRCA2 (Breast cancer genes 50-80% lifetime risk)

Common conditions where family history relevant? - Cancer, Cardiovascular Disease, Diabetes

How does a positive family history affect the consultation for these patients?

3 Genogram

4 Draw Genogram

Billy’s uncle Teddy is the youngest of 4 children, his older sister is married to Mark. Billy’s grandparents married in 1947 and are both alive and well. Billys brother has red hair (but neither of his parents did). His mother died in 1997. His father remarried in 2005.

Draw a genogram indicating the genetic anomaly ‘redhead’.

If Billy also has cousins named James and Louise, what caused his mothers death?

10 points for correct answer - minus one for every extra clue I draw on your genogram.

Another Genogram

5 Why General Practice?

Skills in counselling

Opportunity for 'staged counselling' (multiple consultations to give information, check response and answer questions)

Requires multi agency Liason (therefore someone to coordinate)

Pitfalls?

Confidentiality

Over-simplification

6 Genetic Testing

a Diagnostic

b Predictive

c Carrier Testing

What is the risk? At what level should we 'reassure' ?

'Can you screen my baby to see if it will be a redhead, my uncle was a redhead and he was teased terribly at school and work so I wouldn't want any of my children to go through that' - discuss.

Resources

Where do we refer?

http://www.ich.ucl.ac.uk/gosh/clinicalservices/Clinical_genetics/InformationforHealthProfessionals

Video on Huntington's

Video on Duchenne's

Links

OMIM:

http://www.ncbi.nlm.nih.gov/sites/entrez?db=omim

Family History:

http://www.aafp.org/afp/20050801/441.html

Genetic Testing:

http://www.ukgtn.nhs.uk/gtn/Home