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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.
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Genetics in Primary Care By Chris and Amit
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 – Who’s Who? Miscarriage (Male Foetus) Female male Male Miscarriage (Female Foetus) female Unborn Female Foetus Sex Unkown p Deceased Male p Unborn Male Foetus
Family Trees – Relationships? Marriage/Partnership Divorce/Separation Consanguineous Children/Siblings Non-identical Twins Identical Twins
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 • 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
Single Autosomal Dominant Autosomal Recessive X linked Chromosomal Multifactoral One copy enough Both copies needed Male disease Female carriers Types of Inheritance Inheritance Schizophrenia Type 2 DM Down’s - Trisomy 21 Edwards – Trisomy 18 Patau – Trisomy 13 Turners XO Klinefelters XXY PCKD NF 1 & 2 Huntington’s Myotonic Dystrophy Osteogenesis Imperfecta Tuberous Sclerosis Familial Hyperchol Familial Breast /Ovarian Ca Colorectal – HNPCC HHT Hereditary Spherocytosis Von Willebrand’s Cystic Fibrosis Sickle Cell disease ß-thalassaemia Haemochromatosis CAH Congenital deafness Alpha-1-antitrypsin def Tay-Sachs Disease Gaucher’s Diease Wilson’s Disease PKU Red/Green Colourblind Haemophilia Duchenne MD Becker’s MD
Single Autosomal Dominant Autosomal Recessive X linked Chromosomal Multifactoral Let’s see how awake you were!!! Inheritance
Down’s Syndrome – Trisomy 21 • Risk increases with maternal age and if previous pregnancies have been affected • Age of mother Risk • 20 years 1:1500 • 30 years 1:800 • 35 years 1:270 • 40 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 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/forpatients/departments/genetics/home.aspx
Useful Websites • www.geneticseducation.nhs.uk • www.library.nhs.uk/geneticconditions