Molecular Pathology & Diagnostics Flashcards
Pathology
Study of disease
Molecular Pathology
Application of techniques of molecular biology to the study of disease
Factors in Human diseases
Genetically determined
Environmentally determined
Almost all combination of genetics and environmental factors
Major categories of genetic disorders
Mendelian disorders-single gene defect
Polygenic-multifactorial (most diseases)
Chromosomal (cytogenetic)-change in large amount of DNA
Inherited diseases / germline
Autosomal dominant
Autosomal recessive
X-linked
Multifactorial (polygenic)
Acquired / somatic
Not inherited
occurs in subset of cells
not passed to children
Alteration to DNA sequences
Absent gene product
Abnormal gene product
Disorder of gene regulation
Types of genetic lesions
Chromosomal deletions
Chromosomal translocations
Mutations–from insertions, deletions, point mutations
Gene amplification –copies of gene
Cytogenetics
Identifies: extra, missing, abnormal chromosomes
Translocations
Large insertions and deletions
FISH
Visualizes proximity or separation of two sequences
FISH–Advantages
Higher sensitivity for specific alteration
Can use interphase cells
FISH–Disadvantages
Only detects targeted alterations
Molecular detection methods
PCR
Restriction enzyme fragment analysis
Sequencing
Proteomics-protein fragment analysis
Molecular detection methods applications:
Heritable diseases
Cancer
Infectious diseases
Pharmacogenomics
Heritable Diseases Examples:
Cystic fibrosis-mutation in CFTR gene
Sickle Cell disease-mutation in beta globin gene
Huntington’s chorea- gene amplification
Common chromosomal abnormalities
Common chromosomal abnormalities:
Autosomal trisomies: 21, 18, 13 Digeorge syndrome : 22q11 deletion Sex Chromosome abnormalites: XO-Turner syndrome XXY-Kleinfelter Syndrome
`Down syndrome increases risk of
leukemia, Alzheimer’s Disease (in 40s)–3 copies of Alz-linked genes
Cystic fibrosis
Inherited CFTR defect (chloride channel)
Produces abnormal thick secretions–in lung, pancrease
CF screening detects
Mutations occur all over gene.
delta-F508 most common CFTR mutation
(recessive autosomal)
Molecular diagnostics applied to cancer
Initial diagnosis Classification for prognosis Evaluation for residual disease Monitor for relapse Identify most appropriate therapy
Molecular techniques to infectious disease
Diagnosis
Monitoring therapy–viral loads
Genotyping-characterize organism
Epidemiology–common origins
Pharmacogenomics
Identification of genetic markers response to pharmacologic agents
SNP
Copy number variants are common
Not a dysfunctional mutation or genetic lesion
Alleles-variation in human population
Xenobiotic metabolism depends on six genes:
CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4
CYP alleles can result in ___, ___, or increased enzyme activity, thereby affecting the rate of drug metabolization
absent, decreased
CYP alleles variation lead to;
Normal metabolizers
Poor metabolizers
Ultrafast metabolizers
Short term anticoagulation
Heparin
Long term anticoagulation
Coumadin
Coumadin CYP gene
CYP2C9
Coumadin targets
VKORC1–vitamin K epoxide reductase
CYP2C9*2 or *3 poor metabolizers
Have trouble with?
over-anticoabulation when on Coumadin
VKORC1 A requires a much lower dose of ___
Coumadin
Coumadin-related complication of CYP2C9 polymorphisms
Under anticoagulation–can lead to pulmonary embolism (fatal)
Coumadin-related complication of CYP2C9 polymorphisms
Over anticoagulation–leads to hemorrhage
Chronic myelogenous leukemia
Translocation between abl and bcr genes
Philadelphia chromosome: t(9;22)(q34;q11)
Diagnostics for CML
cytogenetics, FISH, PCR
Specific therapy for CML
Gleevec (Imatinib) TK inhibitor, other TK inhibitors
HER2/neu
Proto-oncogene on Chromosome 17
Her2
Gene amplification (2copies) leads to cancer. Poor response to Tamoxifen
Her 2 is treated with
Herceptin-Traztuzumab
