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Oral health and genetics

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Oral Health and Genetics

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Oral health and genetics

  1. 1. Oral health and Genetics Dr Sharanya Sreekumar Post graduate student Department of Public Health Dentistry
  2. 2. Contents Introduction Laws of inheritance by Mendel Genetics and dental caries Genetics and periodontitis Genetics and oral cancer Classification of genetic disorders
  3. 3. Genetic disorders of oro-facial region • Disorders of jaw bones • Disorders of oral mucosa • Disorders of affecting enamel • Disorders affecting dentine • Miscellaneous disorders Genetic counseling Conclusion References
  4. 4. Introduction The word genetics is derived from ancient Greek “genesis” meaning the origin Imre Festetics was first person to term word genetics before Mendel.
  5. 5. Terminologies Genotype- is the total genetic constitution of an individual Phenotype- refer to a specified character Chromosome: are rod-like condensations of chromatin. They become visible in the nucleus only during cell division Genes: are fundamental units of inheritance
  6. 6. Genetics Modern genetics start with Gregor Johann Mendel.  His works on monohybrid and dihybrid cross level on garden peas mentioned 3 laws of inheritance Law of dominance Law of segregation Law of independent assortment
  7. 7. Genetics in oral health Everything from the alignment of your teeth to their strength can be linked to genetics. The reasons for this disparity are numerous, but one of the key factors is a person’s genetic makeup.
  8. 8. Genetics and dental caries Children manifest the mother’s immune system for the first months of life This acquired immune system is not particularly effective against strains of S mutans in the mother Inherited disorders increases chance of caries.
  9. 9. Risk assessment
  10. 10. “genetic factors play an appreciable part in determining individual resistance against dental caries". ( Book and Grahen, 1953) Twin studies Finn and Caldwell in 1963, found that smooth surface lesion under genetic strict control.
  11. 11. Genetics and periodontitis In periodontitis, the host- activated inflammatory and immunological cascades, which result in the destruction of connective tissue and bone are under genetic control.
  12. 12. Studies In a large, five-generation family, an autosomal-dominant form of localized juvenile periodontitis was ascertained to be linked to Gc (group-specific component, a vitamin-D-binding protein locus) on the long arm of chromosome 4 (4q) (Boughman et al, 1986)
  13. 13. Syndromes associated with periodontitis
  14. 14. Genetics and oral cancer Oral carcinogenesis is a multifactorial process involving numerous genetic processes that can alter the function of oncogenes, tumor suppressor genes, and other related molecules.
  15. 15. These changes causes loss of tumor suppressor activity and give rise to a phenotype capable of increasing cellular proliferation, weakening cell cohesion and causing local infiltration and metastasis.
  16. 16. More than 90% of oral cancer is oral squamous cell carcinogenesis which caused due to genetic alterations Other molecules associated are COX-2 EpCAM MMP-2,6
  17. 17. Genetic disorders There are three types of genetic disorders: Single-gene disorders  Chromosomal disorders disorder Complex disorders Genetic test on blood and other tissue can identify genetic disorders Amniocentesis genetic test.
  18. 18. Genetic disorders of oro facial regions Most of the disorders affecting orofacial region are autosomal dominant trait Disorder mainly affects jaws, dental tissues and oral mucus membrane
  19. 19. Disorders of Jaw bones Cherubism : It is a autosomal dominant disorder Caused due to mutation SH3BP2 gene.( 80% cases)  causes inflammation in the jaw bones and triggers the production of osteoclasts
  20. 20. Cleidocranial dysplasia It a autosomal dominant disorder affecting development of bones and teeth. Mutation of RUNX2 gene abnormally short protein or gene is missing Interferes with normal protein growth and development
  21. 21. Treacher Collins syndrome( mandibulo facial dysostosis) Autosomal dominant trait mutation of gene EFTUD2 Spliceosomes helps process of messengerRNA impairs RNA processing
  22. 22. Nevoid basal cell carcinoma syndrome It is autosomal dominant trait Mutation of PTCH 1 gene occurs Prevent production of patched-1 Cannot effectively suppress cell growth and division Cell grow uncontrollably to form tumour
  23. 23. Osteogenesis imperfecta It is autosomal dominant trait and sometimes have a recessive trait  8 types have been identified. Mutations in the COL1A1, COL1A2, CRTAP, and P3H1 genes Reduces amount of type 1 collagen Causes brittle bones, defective CT
  24. 24. Apert syndrome Autosomal dominant trait Mutation in FGFR 2 gene Alters FGFR287100 protein Leads to prolonged signaling Promote fusion in skull, hand and feet
  25. 25. Disorders of oral mucosa Multiple endocrine neoplasia syndrome Neurofibromatosis Peutz-Jeghers syndrome
  26. 26. Multiple endocrine neoplasia syndrome Tumors produced in endocrine glands. Mutations in the MEN1 type 1 MEN Menin protein RET gene type 2 MEN over activate protein signaling CDKN1B genes type 4 MEN ses amount of functional p27
  27. 27. Neurofibromatosis NF type 1 autosomal dominant Mutations in the NF1 gene nonfunctional version of neurofibromin cannot regulate cell growth and division. neurofibromas forms along nerves .
  28. 28. Peutz-Jeghers syndrome Inherited in autosomal dominant pattern Mutation of STK11 gene alters the structure or function of the STK11 protein disrupting its ability to restrain cell division. formation of noncancerous polyps and cancerous tumors
  29. 29. Disorders affecting dental tissues Amelogenesis Imperfecta Oculo-dentodigital Dysplasia Epidermolysis bullosa Focal dermal hypoplasia Dentinogenesis imperfecta
  30. 30. Amelogenesis Imperfecta 14 forms of amelogenesis imperfecta. Mutations in the AMELX, ENAM, MMP20, and FAM83H genes tooth enamel is abnormally thin or soft  malfunction of the proteins in the enamel: ameloblastin, enamelin, tuftelin and amelogenin.
  31. 31. Hypoplastic type Very less or no enamel Hypomaturation type Snow capped teeth Hypocalcification Soft and easily removable Hypoplasic hypomaturation with taurodontism
  32. 32. Oculo-dento digital Dysplasia Inherited autosomal dominant pattern
  33. 33. Epidermolysis bullosa Usually autosomal dominant pattern 4 major types mutations in either the KRT5 or KRT14 gene. Prevent the keratin proteins from assembling into strong networks causing cells in the epidermis to become fragile and easily damaged. the skin is less resistant to friction and minor trauma and blisters easily.
  34. 34. Focal dermal hypoplasia It is X-linked dominant pattern that primarily Mutations in the PORCN gene prevent the production PORCN protein Wnt proteins cannot be released from the cell Interuptes normal development
  35. 35. Dentinogenesis imperfecta  autosomal dominant condition
  36. 36. DI type 2 and 3 caused to mutation of gene DSPP The DSPP gene provides two proteins that are essential for normal tooth development. DSPP gene mutations alter the proteins made from the gene production of abnormally soft dentin. DI type 1 associated with osteogenesis imperfecta
  37. 37. Miscellaneous disorders Erythroblastosis foetalis Progeria( Hutchnison Gliford syndrome) Scleroderma Cleft lip and palate
  38. 38. Erythroblastosis foetalis Rh incompatablity caused due to mutation of RHAG gene( Rh associated glycoprotein ) It leads to chronic hemolytic anaemia due to defect in RBC formed.
  39. 39. Progeria( Hutchnison Gliford syndrome) rapid appearance of aging beginning in childhood Mutations in the LMNA gene production of an abnormal version of the lamin A protein. nuclear envelope unstable and progressively damages the nucleus making cells more likely to die prematurely
  40. 40. Scleroderma It is autoimmune disorder IRF5 and STAT4, are also associated with an increased risk of developing systemic scleroderma  a combination of genetic and environmental factors seems to play a role in developing systemic scleroderma
  41. 41. Van der woude syndrome Autosomal dominant condition  A shortage of the IRF6 protein affects the development and maturation of tissues in the face.
  42. 42. Genetic counselling is a communication process in which trained professionals help individuals and families deal with issues associated with the risk of or occurrence of a genetic disorder. Types Prospective and Retrospective genetic counselling
  43. 43. Conclusion The traditional epidemiologic approach has proved useful for generating hypotheses and unraveling disease etiologies. But now it is possible to go beyond these methods and look inside the genetics of the disease process which would be able to change the definition of the risk factors or clarify their location in the casual model. The control of genetic diseases should be based on an integrated and comprehensive strategy combining best possible treatment and prevention through community education, population screening, genetic counseling, and the availability of early diagnosis
  44. 44. References Shafer'S Textbook Of Oral Pathology (6th Edition) (2009) edited by R. Rajendran, B. Sivapathasundharam Purkait SK Essentials of Oral Pathology 3rd edition 2011 Rai R, Kumar PG Genetics and oral health. Dentistry and Medical Research Jan-Jun 2016; 4(1): 9-17 Werneck RI, MT Mira M, PC Trevilatt PC . A critical review: an overview of genetic influence on dental caries. Oral Diseases (2010) 16, 613–623
  45. 45. 1000 Genomes Project Consortium. A global reference for human genetic variation. Nature. 2015 Oct 1;526(7571):68-74. Hamosh A, Scott AF, Amberger JS, Bocchini CA, McKusick VA. Online Mendelian Inheritance in Man (OMIM), a knowledgebase of human genes and genetic disorders. Nucleic acids research. 2005 Jan 1;33(suppl_1):D514-7. Govindaraju P. Chandra P. Implications of genomics in oral health. Journal of Advanced Clinical & Research Insights (2015), 2, 147–150 Tyagi R, Sharma A, Khatri A. Genetic Basis of Dental Disorders: A Review. J Oral Health Comm Dent 2008;2(3):55-61
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Oral Health and Genetics

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