Clinical Genetics in Heart Function Services

Transcription

1 Clinical Genetics in Heart Function Services Dhavendra Kumar Consultant/ Hon. Professor Clinical Geneticist & Lead- Cardiovascular Genetics Institute of Medical Genetics University Hospital of Wales Cardiff

2 Burden of genetic heart disease Congenital heart disease (isolated/ syndrome) Marfan syndrome Familial hypercholestrolaemia Inherited cardiomyopathies Inherited arrhythmias Coronary heart disease Hypertension Secondary to other genetic conditions- metabolic/ muscle 1 in in 5,000 1 in in 300 Not known -Long QT+ others= 1 in 2,000 Common polygenic Common polygenic TRUE PREVALENCE OF GENETIC HEART DISEASE UNKNOWN LIKELY TO BE ~30%, PROBABLY MORE THAN CANCER??

3 Spectrum of Inherited Cardiovascular Conditions CHROMOSOMAL MENDELIAN SINGLE GENE POLYGENIC/ MULTIFACTORIAL MITOCHONDRIAL

4 Heart Diseases in Clinical Genetics Primary Cardiomyopathies Arrhythmias Vascular conditions- Ehlers Danlos type IV Multi system-marfan syndrome Secondary Familial hypercholesterolemia Connective tissue diseases Adult manifestations of congenital heart (GUCH) Uncommon metabolic diseases, e.g. Fabry s

5 Presentation Asymptomatic Non-specific symptoms Syncopal episodes Chest pain and breathlessness Abnormal ECG changes Chronic heart failure Sudden unexplained/ cardiac death Family history

6 Referral Guidelines for Individuals with a History of Inherited Cardiovascular Condition We recommend you consider a referral if one or more of the following criteria are met Sudden Unexplained/Cardiac Death Marfan Syndrome and/or Aortic Dilatation/Rupture Congenital Heart Disease Cardiomyopathies Arrhythmias Other Cardiovascular Conditions Referral Criteria with examples Exclusions Recent diagnosis or a First degree relative (parent, siblings, child) affected with an inherited cardiovascular condition (for example Marfan syndrome, Long QT syndrome, Brugada syndrome, hypertrophic cardidiomyopathy) Family history of sudden unexplained/ cardiac death in a close relative Sudden unexplained death in the family leading to a coroner s postmortem/inquest Family history of an inherited cardiovascular condition Individuals identified with an inherited cardiovascular condition through cascade testing in the extended family Age related heart disease Symptomatic patients requiring cardiac assessment, refer direct to Cardiology

7 ACCESSING GENETIC SERVICES FOR INHERITED CARDIOVASCULAR CONDITIONS (ICCs) PATIENT REFERRAL Please see referral criteria NOTE: symptomatic patients who have not had a cardiology assessment will require a referral to their local Cardiology services DISTRICT INSTITUTE OF MEDICAL GENETICS WORK UP WITH FAMILY District genetics clinic +/- testing Specialist Cardiac genetics clinic +/- testing No further action Cardiology assessment No further action RESULTS, OUTCOMES AND LETTERS PATIENT REFERRER G.P. OTHERS

8 Role of Clinical Genetics in ICC Genetic heterogeneity Clinical variation Low or late penetrance? Molecular genetic testing: - many genes - many mutations/ variants - specificity & sensitivity - pathogenic or polymorphic - technical/cost Other genes or genetic factors? relevance Dealing with at-risk family members Risk assessment Reproductive options Life style choices

9 Genetic Counselling

10 Heterogeneity of CHF Genetic HCM DCM VNC Toxic- Alcohol Ischaemia CAD Chemotherapy Heart Failure Hypertension Post myocarditis Post Rheumatic Metabolic T2DM Congenital Ht

11 Genetic Factors in Inherited Cardiomyopathies Modifier genes Epistasis Causal mutation Cardiomyopathy Phenotype Epigenetics Environment Post translational Transcriptional modifications

12 Genetics and Heart Failure INHERITED CARDIOMYOPATHIES MONOGENIC OLIGOGENIC POLYGENIC SYSTOLIC AND DIASTOLIC HEART FAILURE

13 GENETICS and Cardiomyopathies MORE THAN 60 KNOWN DISEASE GENES > 30 DCM >15 HCM >7 ARVC/D >5 NONCOMPACTION VD >5 AMYLOID CM

14 GENETIC HETEROGENEITY IN FAMILIAL HCM

15 Molecular Pathology-HCM Sarcomeric/cytoskeletal proteins Thick and thin filaments ~15 sarcomere genes Various mutations- missense; point etc. >400 Several polymorphisms? pathogenic No unifying sarcomeric hypothesis of pathogenesis

16 Genotype-Phenotype correlation In most cases no correlation Weak correlation with SCD (TnT) Age related penetrance- MYBPC3 Penetrance(% ) yrs MHC TnT MyBPC

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18 Ventricular Non-Compaction Developmental Heterogeneous May be part of congenital heart disease May be part of chromosomal disorder May complicate familial DCM Characteristic pathology Several genes/proteins Sarcomere genes most common

19 Ventricular Non-compaction Hypertrophic Cardiomyopathy Dilated Cardiomyopathy

20 Molecular Genetic Testing Specific genetic label to the clinical diagnosis Specific disease-causing mutation in the family Accurate genetic counselling to the index case Option for prenatal/pre-implantation diagnosis Predictive genetic testing in close relative Reproductive choices to the mutation positive person Supporting the cardiology team for planning/ offering effective/ efficient long-term clinical surveillance Option for preventive measures- medication/ devices

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22 Limitations of molecular genetic testing Genetic heterogeneity- gene selection Mutation heterogeneity Variants of unknown significance Poor genotype-phenotype correlation- limited prognostic information/ clinical outcome prediction Testing protocols-conventional Cardiomyopathy genes chip New generation testing methods Cost/ Funding/ commissioning

23 FAMILY 1 71 yrs; CHF HCM; MYBPC3 64 yrs, known HCM Ch. Heart failure MYBPC3 variant 70 yrs 74 yrs 3 CALs?NF1 SPRED1 N-CVS MYBPC3 9 yrs CALs Breathless 32yrs 24 yrs-n-echo Abn ECG?HCM Sudden Histopathology? MYBPC3 mutation or variant? 15 yrs N-CVS 33 yrs N-ECHO

24 MYBPC3 in two families c1457 c1624 Exon16 Exon17 +5G>C +4A>T Family 1 Family2

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26 When should molecular genetic testing be considered? In all cases of sudden unexplained death under 45 years- bank DNA from spleen Index case with family history of proven ICC Index case with family history of unexplained heart disease and/or sudden death Index case with unclear clinical diagnosis Request for prenatal diagnosis/ pre-implantation diagnosis- confirm pathogenic mutation in the index case Predictive/ presymptomatic testing in a close relative if known pathogenic mutation/variant in the index case- follow relevant protocol/ guidelines LOW THRESHOLD FOR BANKING DNA

27 How does AWMGS support Heart Functions Services? Dealing with the family in the tragic event of sudden cardiac death in the family Clarification of clinical variation in the family history Several genes may manifest with the same clinical, radiological and pathological phenotypes Genetic counselling offers wide-ranging support to close relatives and the extended family Identification of the disease-causing gene in the index patient- crucial for accurate risk assessment/ genetic counselling for other family members* Targeted genetic testing in the unaffected at-risk relative offers opportunity for effective and efficient multi-disciplinary clinical surveillance* Reproductive / life style options for the affected/mutation positive persons

28 Cardiomyopathy care pathway Primary care Hospital specialist Family/ Community Referral Clinical Genetics Cardiology team Cardiac genetic counsellor Cardiomyopathy Nurse Clinical geneticist Cardiologist Cardiogenetic MDT Structural Heart Genetic care Clinical care

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