Role of clinical genetics in medicine

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Role of clinical genetics in medicine
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Who provides this service

• Varies depending on structure and funding of
  service but is in reality provided by many
  different individuals
• Medical genetic staff
• Physicians and surgeons with a special interest
• Nurses with a special interest
• Obstetricians
• General practitioners

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Clinical Genetic Service

• Cytogenetic laboratory
• Molecular genetic laboratory
• Clinical genetics

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Clinical Genetics

• Diagnosis of genetic disorders
• Provide information to individuals and families
  about the genetic disease affecting their family
• Clinical surveillance of individuals at risk of
  genetic disease
• Coordination of screening of at risk individuals
• Laboratory liaison
• Education

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Clinical genetics

• Mainly an outpatient speciality
• Patients seen
• In clinic
• At home
• On the ward

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Diagnosis

• May be known prior to the appointment and
  inheritance of condition in the family known
• May be made in clinic from history and
  examination
• May be unknown but pedigree analysis may help in
  establishing risks

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Diagnosis

• Clinical geneticists are specifically trained to
  recognise genetic disease through
• Pedigree analysis
• Phenotypic and pattern recognition
• Individual patient research

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Appropriate investigation

• Appropriate investigation of complex disorders as
  a result of phenotypic and pattern recognition of
  the individual and family
• Use of medical genetic databases
• Knowledge on available genetic testing

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Diagnosis of genetic disease

• Each genetic disease is rare and genetic
  practitioners are more likely to recognise a
  condition because they may have seen it or have
  read about the condition before
• Physicians and surgeons with a special interest
  may also have extensive knowledge of a particular
  group of genetic conditions

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The process

• Taking the family tree
• Collecting the medical history in detail
• Examination of the affected or at risk individual
  if appropriate

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Surveillance

• Knowledge of disorder allows appropriate clinical
  surveillance of individuals at risk of genetic
  disease
• Development of guidelines for the management of
  individuals at risk
• Coordination of screening of at risk individuals

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Providing the information

• Non directive
• Non judgmental
• Fully informative

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Clinical counselling

• Affective communication with family about the
  natural history and prognosis of genetic disease
• Provide risk information for relatives including
  offspring
• Prenatal/antenatal counselling
• Provide support for individuals and families with
  genetic disease

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Genetic Counselling

• An educational process that seeks to assist
  affected and/or at risk individuals to understand
  the nature of the genetic disorder, its
  transmission and the options open to them in
  management and family planning
• Kelly 1986

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Genetic counselling

• Genetic counselling is the process by which
  patients or relatives at risk of a disorder that
  may be hereditary are advised of the consequences
  of the disorder, the probability of developing or
  transmitting it and of the ways in which this may
  be prevented, avoided or ameliorated

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Associate/nurse led clinics

• Tend to be disease specific
• Provide information about the risks and natural
  history, including complications
• Work to frequently reviewed guidelines
• Provide emotional support for individuals and
  families with genetic disorders

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Providing support

• Support and counsel individuals considering and
  during genetic testing
• Diagnostic
• Predictive
• prenatal
• Provide bereavement and post termination
  counselling
• Ensuring families receive available services and
  benefits

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Clinical Genetics - laboratory

• Clinical support for cytogenetic and molecular
  genetic laboratories including the
  interpretation of results in the clinical context
• Liase with other clinicians using genetic
  laboratory services

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Pharmacogenetic

• Currently clinical genetic departments are rarely
  involved, however this may change as more sub
  typing of disease and individuals becomes possible

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Pharmacogenetics
Disease susceptibility
Focused screening
Early Diagnosis
Targeted therapy
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Pharmacogenetics
Clinical diagnosis
Biochemical diagnosis
Genotype diagnosis Somatic or germline
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Genotype diagnosisPredicting drug response

• Diabetes
• HLA, HNF1a and 4a, PPAR, glucokinase
• e.g. sulphonylurea very affective in HNF1a
• Asthma
• IGE receptor, airway remodelling, epithelial
  barrier (protease)
• Cancer
• Imantinib active against tumours with activated
  KIT mutations (GISTs), 82 response rate
• Herceptin for Ca breast with ERBB2 over
  expression

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Clinical Genetics

• Diagnosis of genetic disorders
• Provide information to individuals and families
  about the genetic disease affecting their family
• Clinical surveillance of individuals at risk of
  genetic disease
• Coordination of screening of at risk individuals
• Laboratory liaison
• Education