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Dr Mohammad Hasan Sheikhha , M.D., Ph.D. Shahid Sadoghi Medical University, Yazd, Iran

Molecular Genetics Lab. Dr Mohammad Hasan Sheikhha , M.D., Ph.D. Shahid Sadoghi Medical University, Yazd, Iran. If all the DNA in ten human nuclei were enlarged to a full-sized continuous ladder, it could reach more than 30 million miles, or from the earth to the planet Mars:.

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Dr Mohammad Hasan Sheikhha , M.D., Ph.D. Shahid Sadoghi Medical University, Yazd, Iran

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  1. Molecular Genetics Lab Dr Mohammad HasanSheikhha, M.D., Ph.D. ShahidSadoghi Medical University, Yazd, Iran

  2. If all the DNA in ten human nuclei were enlarged to a full-sized continuous ladder, it could reach more than 30 million miles, or from the earth to the planet Mars:

  3. (length of 1 bp)(number of bp per cell)(number of cells in the body) • (0.34 × 10-9 m)(6 × 109)(1013) • 2.0 × 1013 meters • That is the equivalent of nearly 70 trips from the earth to the sun and back.

  4. The Central Dogma of Molecular Biology

  5. Clinical Applications of Molecular Diagnosis CA García-Sepúlveda MD PhD Viral & Human Genomics LaboratoryFacultad de Medicina, Universidad Autónoma de San Luis Potosí Laboratorio de Genómica Viral & Humana - Facultad de Medicina - Universidad Autónoma de San Luis Potosí Mexico

  6. Molecular Diagnostics Industry $5.5 Billion industry $8 Billion by 2010 40 million annual test volumes in the U.S. Projected to be 1/3 of all diagnostic testing Laboratorio de Genómica Viral & Humana - Facultad de Medicina - Universidad Autónoma de San Luis Potosí

  7. Industry Test Volumes & Applications 55% - Infectious disease 23% - Blood Screening 13% - Genetic Testing 7% - Cancer. Prediction of risk – Oncotype. Early detection - Fragile X. Classification of disease – Leukemias. Therapeutic homming of presumptive target. Prediction of toxicity & response – Herceptin. Laboratorio de Genómica Viral & Humana - Facultad de Medicina - Universidad Autónoma de San Luis Potosí

  8. Breast Cancer and Targeted Therapy 211,000 women diagnosed with breast cancer and 40,000 deaths per year (US 2005 estimate). Herceptin (trastuzumab) chemotherapy approved by the FDA in 1998. Risk of congestive heart failure. Herceptin could benefit women who over-expressed a protein – HER2/Neu. Molecular diagnostic tests reveal who could and will not benefit from Herceptin. Herceptin benefit test Cost $500 USD Herceptin Tx costs $25,000 – $80,000 Getting the “right” women on Herceptin Laboratorio de Genómica Viral & Humana - Facultad de Medicina - Universidad Autónoma de San Luis Potosí

  9. Coumarin Pharmacogenomics Warfarin is an oral anticoagulant that inhibits vitamin K reductase. Discovered 60 years ago and currently one of the most prescribed drugs in the world. Used to prevent thromboembolisms due to atrial fibrilation, recurring miocardial strokes, Deep vein thrombosis, Pulmonary thromboembolism and that due to valve replacements. Between 1 and 7% of treated patients will suffer lethal hemorrhagic complications (very tight therapeutical safety index). CYP2C9 & VKORC1 polimorphisms define metabolic rates and might explain between 10 and 25% of interindividual therapeutic response variations. “The FDA highlights the opportunity for healthcare providers to use genetic tests (CYP2C9 & VKORC1) to improve their initial estimate of what is a reasonable warfarin dose for individual patients”. Laboratorio de Genómica Viral & Humana - Facultad de Medicina - Universidad Autónoma de San Luis Potosí

  10. Cytogenetic tests FISH Molecular tests Genetic Diagnostics

  11. Molecular Diagnostics • Diagnosis of infectious diseases • Genetic identification • Diagnosis of genetic diseases

  12. Infectious Diseases • MRSA • VRE • Group A Strep • Group B Strep • TB • HIV • HCV • CMV • Flu • Stop me when you’re bored…

  13. Why use a molecular test to diagnose an infectious disease? • Need an accurate and timely diagnosis • Important for initiating the proper treatment • Important for preventing the spread of a contagious disease

  14. Leading uses for genetics tests • Nonculturable agents • Human papilloma virus • Hepatitis B virus • Fastidious, slow-growing agents • Mycobacterium tuberculosis • Legionella pneumophilia • Highly infectious agents that are dangerous to culture • Francisella tularensis • Brucella species • Coccidioidis immitis

  15. Leading uses for genetics tests • In situ detection of infectious agents • Helicobacter pylori • Toxoplasma gondii • Agents present in low numbers • HIV in antibody negative patients • CMV in transplanted organs • Organisms present in small volume specimens • Intra-ocular fluid • Forensic samples

  16. Leading uses for genetics tests • Differentiation of antigenically similar agents • May be important for detecting specific virus genotypes associated with human cancers (Papilloma viruses) • Antiviral drug susceptibility testing • May be important in helping to decide anti-viral therapy to use in HIV infections • Non-viable organisms • Organisms tied up in immune complexes

  17. Leading uses for genetics tests • Molecular epidemiology • To identify point sources for hospital and community-based outbreaks • To predict virulence • Culture confirmation

  18. Genetic Identification - Paternity Testing - Forensics

  19. Diagnosis of genetic diseases - Somatic rearrangements in cancer - Genetic risk factors • Pharmacogenetics - Mutations in monogenic diseases

  20. Rearrangements in Cancer Cells Chromosomal breaks produce fusion genes These cause leukemias and lymphomas Diagnosis determines treatment and prognosis

  21. Rearrangements in Cancer Cells Lymphocytic Leukemia t(9;22) : BCR - ABL t(12;21) TEL - AML1 t(1;19) : E2A - PBX1 t(4;11) : MLL - AF4 Myeloid Leukemia Inv(16) CBF - MYH11 t(8;22) : AML - ETO t(9;22) : BCR - ABL

  22. Diagnosis of genetic diseases - Somatic rearrangements in cancer - Genetic risk factors • Pharmacogenetics - Mutations in monogenic diseases

  23. Genetic Risk Factors Monogenic diseases are caused by a deleterious mutation in a single gene: Disease-causing mutations Multifactorial diseases are caused by a combination of variations in multiple genes: Genetic Risk Factors

  24. Genetic Risk Factors Deep venous thrombosis Cardiovascular disease Alzheimer disease Osteoporosis

  25. Genetic Risk Factors Deep venous thrombosis Factor V Factor II MTHFR

  26. Diagnosis of genetic diseases - Somatic rearrangements in cancer - Genetic risk factors • Pharmacogenetics - Mutations in monogenic diseases

  27. Pharmacogenetic tests • Drug specificity • Drug efficacity - toxicity

  28. Drug specificity Herceptin :HER2 Tyrosine kinase inhibitors BCR / ABL KIT PDGFR A/B EGFR

  29. Pharmacogenetics • Warfarin metabolism • Polymorphisms • VKORC1 • Vitamin K epoxide reductase complex 1 • CYP2C9 • Part of cytochrome P450 family • FDA testing recommended

  30. Diagnosis of genetic diseases - Somatic rearrangements in cancer - Genetic risk factors • Pharmacogenetics - Mutations in monogenic diseases

  31. Diagnostic bottle necks • Number of diseases • Nature of disease mutation • Technology • Cost • Number of samples • Organisation

  32. Diagnostic bottle necks • Number of diseases • Nature of disease mutation • Technology • Cost • Number of samples • Organisation

  33. Disease Mutations Easy tests : Single - common mutations Difficult tests : Private mutations

  34. Disease Mutations Single mutationsFragile X Sickle Cell Anemia Common mutationsDeafness Hemochromatosis Panel of mutationsCystic Fibrosis Private mutationsBreast Cancer Colorectal cancer

  35. BRCA testing BRCA1 : 23 exon, 1863 AA, 6.200 bp BRCA2 : 28 exon, 3418 AA, 10.300 bp Total : > 17.000 bp sequence

  36. Diagnostic bottle necks • Number of diseases • Nature of disease mutation • Technology • Cost • Number of samples • Organisation

  37. Mutation Detection 1. Point mutations, frame shifts : A. Sequencing B. WAVE 2. Deletions : MLPA

  38. Molecular Diagnostics 60 % 40 20 Deletion Duplication Point DNA Diagnostic Systems Example: Diagnostic for Duchenne Muscular Dystrophy (DMD) • X-linked and affect mainly males an estimated 1 in 3500 boys worldwide • DMD encodes a large structural protein: dystrophin • strengthen muscle cells by anchoring elements of the internal cytoskeleton to the surface membrane • Mutated dystrophin leads to ”implosion” of muscle cells DMD Mutation Types

  39. Molecular Diagnostics Minisequencing by primer extension DNA Diagnostic Systems Sequencing DNA polymerase + one of the four labeled dNTPs = sequencing of one nucleotide -> HPLC analysis

  40. Thank you

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