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?

p

p

Female

Male

Sex Unkown

Deceased Male

Miscarriage (Male Foetus)male

femaleMiscarriage(Female Foetus)

Unborn FemaleFoetus

Unborn Male Foetus

Family Trees – Relationships?

Marriage/Partnership

Divorce/Separation

Consanguineous

Children/Siblings

Non-identical Twins

Identical Twins

Family Trees - Example …

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

Drawing a Family Tree – Simple Tips

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

Mutation / Mutant

Defective / Damaged

Disease / Problem

Sufferer

Risk

Neutral

Variation / Variant

Changed / Altered

Condition

Person with a condition

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

Single

Chromosomal MultifactoralAutosomalDominant

AutosomalRecessive

X linked

One copy enough Both copies needed Male disease

Female carriers

Inheritance

PCKDNF 1 & 2

Huntington’s Myotonic Dystrophy

Osteogenesis ImperfectaTuberous SclerosisFamilial Hyperchol

Familial Breast /Ovarian CaColorectal – HNPCC

HHTHereditary Spherocytosis

Von Willebrand’s

Cystic Fibrosis Sickle Cell disease

ß-thalassaemia Haemochromatosis

CAHCongenital deafness

Alpha-1-antitrypsin defTay-Sachs DiseaseGaucher’s DieaseWilson’s Disease

PKU

Red/Green ColourblindHaemophiliaDuchenne MDBecker’s MD

SchizophreniaType 2 DM

Down’s - Trisomy 21Edwards – Trisomy 18Patau – Trisomy 13Turners XOKlinefelters XXY

Let’s see how awake you were!!!

Single

Chromosomal MultifactoralAutosomalDominant

AutosomalRecessive

X linked

Inheritance

Mode of inheritance

Down’s Syndrome – Trisomy 21

Risk increases with maternal age and if previous pregnancies have been affected

Age of mother Risk20 years 1:150030 years 1:80035 years 1:27040 years 1:100

45 years and over 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 DiagnosisAntenatal Risk EstimationPredictive TestingFacilitate Ongoing ManagementPatient InformationEducation of Healthcare Professionals

Local genetic services

http://www.bshg.org.uk/genetic_centres/uk_genetic_centres.htm

http://www.oxfordradcliffe.nhs.uk/forpatients/departments/genetics/home.aspx

Useful Websites

www.geneticseducation.nhs.uk www.library.nhs.uk/geneticconditions