GENETICS 101 An overview of human genetics and practical applications from an adult medical genetics clinic
Historical timeline of genetics Discuss basics of genetics Discuss tools used in clinic Discuss some of the common referrals
Overview of genetics
TIMELINE OF GENETICS 1865: Heredity Transmitted in Units 1869: DNA first isolated 1902: Chromosome theory of inheritance 1909: The word gene is coined 1911: Chromosomes carry genes 1952: Genes are made of DNA 1953: DNA is a double helix 1955: Humans have 46 chromosomes 1956: Disease caused by DNA alteration 1959: Chromosome abnormalities identified
TIMELINE OF GENETICS 1961: First newborn screen for metabolic defect 1966: Genetic code cracked 1975: DNA first sequenced 1983: First disease gene mapped 1990: Human genome project launched 1995: Ban on genetic discrimination in work place 1997: Dolly the sheep is cloned 2003: Human genome fully sequenced 2003: Dolly the sheep is euthanized due to progressive lung disease 2011.
GENETICS: THE BASICS DNA Genes Chromosomes
WHAT HAPPENS WHEN THERE IS AN ERROR IN THE DNA CODE?
Clinical Applications
Cancer Pediatric Prenatal GENETICS Metabolic Adult
ADULT GENETICS Accept physician referred and self referred patients Reasons for referrals: Seek diagnosis of a familial condition Seek diagnosis to describe seemingly unrelated medical issues (stop the diagnostic odyssey ) Family planning Assist with medical management Want to be proactive about health
Adult Genetics Medical history Pregnancy history Developmental history Physical exam Review family medical history Photos (family and patient) Ultimately use these tools to determine diagnosis and/or appropriate tests!
Fabry Disease
FABRY DISEASE (ICD9: 272.7) Gene: GLA (alpha- galactosidase A) Locus: X chromosome Incidence: 1/50,000 males (Italian study 1/3100)
FABRY DISEASE Brain: cerebrovascular disease Nervous: acroparesthesia, hypohidrosis, pain crises Eyes: corneal whorling Heart: hypertrophic cardiomyopathy, arrhythmia, myocardial infarction, cardiovascular disease Gastrointestinal: cramping, bloating, diarrhea Kidney: proteinuria, progressive renal failure
Fabry Disease: Management Acroparesthesia Renal Disease Cerebrovascular Disease Cardiovascular Disease Enzyme replacement therapy Surveillance
Marfan syndrome
MARFAN SYNDROME (ICD9: 759.82) Gene: FBN1 (fibrillin) Locus: chromosome 15 Incidence: 1/5000; (no gender discrepancy)
MARFAN SYNDROME Eyes: ectopia lentis, myopia Heart: aortic root dilation, aortic root dissesction, mitral valve prolapse Lungs: spontaneou pneumothorax Skeletal: tall, lanky, arachnodactyly, joint hypermobility, pectus deformity, dural ectasia, scoliosis Skin: stretch marks
Marfan Syndrome: Management Eyes Eyeglasses Surgery Cardiac Monitor aorta Surgical intervention Medication Skeletal Surgical correction
Neurofibromatosis 1
NEUROFIBROMATOSIS 1 (ICD9: 237.71) Gene: NF1 (neurofibromin) Locus: chromosome 17 Incidence: 1/3000
Neurofibromatosis 1 Eyes: Lisch nodules, optic glioma Nervous: plexiform neurofibromas, cognitive disability Skeletal: pseduoarthrosis, scoliosis Skin: café-au-lait spots, cutaneous neurofibromas Other: hypertension
Neurofibromatosis 1: Management Surveillance Surgery
Huntington s Disease
Huntington Disease (ICD9: 333.4) Gene: HTT (huntingtin) Locus: chromosome 4 Incidence: 1/10,000
Huntington Disease: Key Features Cognition: Disinhibition, speech difficulties, slowed reaction time Physical: clumsiness, abnormal eye movements, dystonia, involuntary movements, poor balance, tripping/falling, chorea Psychologic: agitation, irritability, anxiety, disinhibition
Huntington Disease: Key Features Rigidity Bradykinesia Severe chorea Serious weight loss Inability to walk Inability to speak Swallowing problems, danger of choking Inability to care for oneself
Huntington Disease: Management Psychological assistance Medication Mitigate physical symptoms Psychiatric Supportive care Feeding tubes Nursing care End of life care
Clinical Genetics: Beyond the disease
Discrimination ADA GINA Affected versus at-risk Duty to warn/inform Implications for other family members Reproductive decision making
THANK YOU Cari Wells, MS CGC Certified Genetic Counselor Adult Medical Genetics Clinic University of Colorado Hospital T: 720-848-6589 Email: cara.wells@uch.edu