Transcript Genetics in Primary care

Genetics in Primary Care
By
Chris and Amit
Ethical Dilemmas
Imagine …
 You are recently married with no children.
 Your Dad died 10 years ago from Huntington’s Disease. Your Mum was his
main carer but his condition dominated your childhood.
 During his illness he became profoundly depressed at an early stage. Two
unsuccessful suicide attempts and a slow slip into alcoholism came before
the dementia characteristic of the disease set in.
 Your partner has suggested that you get Genetic Testing to see if you have
inherited the dominant gene.
 Your Mum has tried to encourage you not to go ahead. She is afraid of how
the answer would affect you.
 Would you be tested?
Spotting a Genetic Condition
 The condition is known to be genetic
 Multiple family members affected
 Early age of onset
 Recurrent miscarriage
 A cluster of different disorders
 An unusual combination of physical features
Family Trees
Family Trees – Who’s Who?
Female
male
Male
Sex Unkown
Deceased Male
Miscarriage
(Male Foetus)
female
Miscarriage
(Female Foetus)
p
Unborn Female
Foetus
p
Unborn Male Foetus
Family Trees – Relationships?
Marriage/Partnership
Divorce/Separation
Consanguineous
Children/Siblings
Non-identical Twins
Identical Twins
Family Trees - Example …
Drawing a Family Tree – Simple Tips
 Start with the patient and immediate family and work out
 Systematically cover each branch fully before moving on
 Always date and sign a completed family tree
 It can be scanned into notes or attached to a referral
Mind your Language with Genetics
Mind your Language
 Other Partners
 Do all your children have the same Mum/Dad?
 Do all your brothers and sisters have the same parents?
 Consanguinity
 Is your partner a blood relative?
 Were you related to your partner before you married?
 Pregnancy Losses
 Have you had any other pregnancies?
 Was there a medical reason to terminate the pregnancy?
Mind your Language
 Negative
 Neutral
Mutation / Mutant
Variation / Variant
Defective / Damaged
Changed / Altered
Disease / Problem
Condition
Sufferer
Person with a condition
Risk
Chance / Likelihood
Mind your Language
Watch out for …
Parental Guilt
Cultural and Religious Influences
Your own Prejudices as a doctor
Your own Assumptions as a doctor
Imagine …
 One of your patients comes to see you
 He recently married and is thinking of having
children
 His wife’s sister has Cystic Fibrosis
 He wants to know if his children would be
affected and what he can do
CSA Roleplay
Types of Inheritance
Inheritance
Single
Autosomal
Dominant
Autosomal
Recessive
X linked
One copy enough
Both copies needed
Male disease
Female carriers
Cystic Fibrosis
PCKD
Sickle
Cell disease
NF 1 & 2
ß-thalassaemia
Huntington’s
Haemochromatosis
Myotonic Dystrophy
CAH
Osteogenesis Imperfecta
Congenital deafness
Tuberous Sclerosis
Alpha-1-antitrypsin def
Familial Hyperchol
Tay-Sachs Disease
Familial Breast /Ovarian Ca
Gaucher’s Diease
Colorectal – HNPCC
Wilson’s Disease
PKU
HHT
Hereditary Spherocytosis
Von Willebrand’s
Red/Green Colourblind
Haemophilia
Duchenne MD
Becker’s MD
Chromosomal
Down’s - Trisomy 21
Edwards – Trisomy 18
Patau – Trisomy 13
Turners XO
Klinefelters XXY
Multifactoral
Schizophrenia
Type 2 DM
Let’s see how awake you were!!!
Inheritance
Single
Autosomal
Dominant
Autosomal
Recessive
X linked
Chromosomal
Multifactoral
Mode of inheritance
Down’s Syndrome – Trisomy 21
 Risk increases with maternal age and if previous
pregnancies have been affected
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


Age of mother
20 years
30 years
35 years
40 years
 45 years and over
Risk
1:1500
1:800
1:270
1:100
1:50 and greater
Down’s Screening – Initial Screening
 This info is from CKS and Patient.co.uk and may vary – please
check the details
 First Trimester Combined Test
 From 11+2 to 14+1 weeks
 Nuchal Translucency Scan/Crown-Rump Length on USS and
Bloods (bHCG + PAPP-A)
 90% sensitivity
 Quadruple Test
 From 14+2 to 20 weeks
 Bloods (bHCG, AFP, uE3 + inhibin A)
 Not as good as First Trimester Combined Test
Down’s Screening – Test to Confirm
 This info is from CKS and Patient.co.uk and may vary – please
check the details
 If Screening Risk > 1/150 then offer further assessment to confirm
 Pre 13 wks gestation
 Chorionic Villous Sampling
 Usually transabdominal needle (sometimes trans-cervical)
 Local anaesthetic and USS guidance
 0.5 – 1% risk miscarriage
 Post 15 wks gestation
 Amniocentesis
 Transabdominal needle, Local Anaethetic and USS Guidance
 1 – 2% risk miscarriage
Role of Clinical Genetics Department
Facilitate Pre-Natal Diagnosis
Antenatal Risk Estimation
Predictive Testing
Facilitate Ongoing Management
Patient Information
Education of Healthcare Professionals
Local genetic services
http://www.bshg.org.uk/genetic_centres/uk
_genetic_centres.htm
http://www.oxfordradcliffe.nhs.uk/forpatient
s/departments/genetics/home.aspx
Useful Websites
www.geneticseducation.nhs.uk
www.library.nhs.uk/geneticconditions