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Understanding Causes of Malformations: Teratogenesis Explained

Explore the various factors contributing to birth defects and congenital anomalies. Dr. Sadatinejad, a medical student from Iran, presents insights on different types of abnormalities and principles of teratology.

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Understanding Causes of Malformations: Teratogenesis Explained

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  1. Causes of Malformations(Teratogenesis or Dismorphology) ? ? ? Presented by DrSadatinejad, SeyyedMohsen,student of Medicine from Iran,Kashan 19/12/2012

  2. Birth defectCongenital malformationCongenital anomaly(Hereditary) abnormality

  3. Types of Abnormalities : • Minor anomalies • Major anomalies • Malformation • Disruptions • Deformations • Syndromes

  4. Principles of Teratology 1- پاسخ (آسیب پذیری) جنین و مادر به عامل تراتوژن 2- مرحله تکاملی جنین (Developmental stage at the time of exposure) 3- دوز و مدت زمان تماس با عامل تراتوژن (Dose and duration of exposure to a teratogen) 4- طریقه عمل تراتوژن : تغییرات در سطح سلولی و مولکولی 5- نتیجه تراتوژن : مرگ، ناهنجاری، عقب ماندگی رشد، بیماری های عملکردی

  5. Hereditary (Genetic) causes 15-18% • Environmental factors 7-10% • Multifactorial 25% • Unknown 50%

  6. First week (Resistant period) • Embryonic period • Maximum susceptibility (organ morphogenesis) • Fetal Period • Lowered Susceptibility (functional derangement)

  7. Genetic factors • 1- اختلالات تعدادي كروموزوم (Numerical Chromosomal Anomalies) • الف) پلي پلوئيدی(Polyploidy) Triploidy 69 يك تخمك هاپلوئيد با دو اسپرم یا تخمک دیپلوئید با یک اسپرم Tetraploidy 92 اولين كليواژ • ب) آنوپلوئيدی (Aneuploidy) تريزومی تريزومي 13 (Patausyndrome) تريزومی 18 (Edwards syndrome) تریزومی 21 سندرم داون (Down syndrome) سندرم كلاين فلتر(Klinfeltersyndrome-XXY) Triple X (Superfemale) مونوزمی سندرم ترنر(Turner syndrome- XO)

  8. Patau Syndrome 1/20000 cleft-lip-baby

  9. Edwards Syndrome 1/5000

  10. Down syndrome • Maternal nondisjunction (95%) • Mosaism • Translocation

  11. Monosomy • Nondisjunction in sperm 80% • Struc X • Nondisjunction in mitosis (Mosaism)

  12. 2- ناهنجاري هاي ساختماني كروموزوم • (Structural Chromosomal Anomalies) • Isochromosome • Crossing over : • Translocation 21,13,14, 15in Down syndrome • Partial Deletion Cri du chat 5(microcephal, mental, cardiovas) • Microdeletion Angelman15 (speech, mental, movement) Prader- willi15 (fatty, mental, hypogonad) • Inversion

  13. 3- ناهنجاري هاي حاصل از جهش ژنی (Gene Mutation Anomalies) • Marphan syndrome • Crigler-Najjarsyndrome • Roberts syndrome • Alportsyndrome • Aarskog-Scott syndrome • Savant syndrome • treacher-collinssyndrome • Niemann–Pick disease • Cystic Fibrosis • DMD

  14. Environmental factors • Infectious Agents (& other disease) • Drugs Agents (& HormonicAgents) • Chemical Agents • Physical Agents

  15. Infectious Agents • A) Viral infections • Rubella virus (German Measles) ویروس سرخجه 1month-From placenta- atrioventricularseptsl defect, cataract. Weight ↓ • Cytomegalovirus(CMV) From Placenta,Cervix,Vagina (& Lactation) - microephaly, deafness, mental retardation, hepatospleenomegally ,cardiac defect,cerebral calcification, blue spot on skin • Herpes simplex virus(HSV) From Placenta,Vagina(85%)-Defect in CNS,liver, pancreas,ren,suprarenal glands, infection on skin, Eyes or mouth – no treatment=40-50% death • Varicella-zoster virus(VZV)آبله مرغان First 3 month-From Placenta- limb hypoplasia & parasis., hydrocephaly. Mental retardation, cataract • HIV After 35th week- Systematic Chronic infection(fangus,bacterial,viral,protozoan)

  16. Infectious Agents • B)Nonviral infections • Toxoplasma in each three munth - death,microcephaly,hydroceohaly,cerebral calcification • Treponemapallidum Syphilis, rhinitis,eye defect(cataract),icterus,abnormal teeth, splenohepatomegaly

  17. بیماری های مادری مرتبط با ناهنجاری • Desease • Diabetes Coudaldisgenesis, death • PKU mental retardation, microcephaly, cardiac defect • Nutrient deficiency Iodine deficiency coused cretinism • Obesity ONTD, cardiac defect, … • Hypoxy

  18. Drugs Agents • Category X drugs • Category D drugs

  19. Clomiphen • Diethylstilbestrol • Ethisterone • Norethindrone • Nicotine • Alcohol Category X drugs • Thalidomide • Aminopterin • methotrexate • Busulfan • Phenytoin • Triazolam • Warfarin • Isotretinoin

  20. Category X drugs • Thalidomide antinauseant drug داروی ضد تهوع • limb defect (Amelia,Meromelia) • Cardiac defect • GIT atresy • Optic & otic defect

  21. Category X drugs • Thalidomide

  22. Category X drugs • Aminopterin • Methotrexate • Busulfan • Used in chemotererapy • Dawerfism • Myelomeningocele • palate clef • Growth retardation • ophtalmic defect

  23. Category X drugs • Aminopterin • Methotrexate • Busulfan • Used in chemotererapy • Dawerfism • Myelomeningocele • palate clef • Growth retardation • ophtalmic defect

  24. Category X drugs • Phenytoin • Antileptic drug • microcephaly • Growth & mental retardation • palate clef • Finger & nail Hypoplesia • Skull defect

  25. Category X drugs • Warfarin • Anti couagulant drug • Mental retardation • microcephaly • optic n. atrophy • Fetal bleeding

  26. Category X drugs • Clomiphen • Non-steroidal drug • Used for stimulus ovulation • Maybe Malformatin

  27. isotretinoin, 13-cis-retinoic acid Category Xdrugs • Retinoids(vitamin A) • Used for Cystic akne • severe craniofacial defects • cardiac defects • neural tube defects (NTD) • Palate cleft tretinoin (Retin-A)

  28. Category X drugs • Nicotine • Mental retardation • Wheight loss • Fetal Hypoxy • Premature Parturition

  29. Category X drugs • Alcohol • Fetal Alcholic Syndrome (FAS) • Mental retardation • microcephaly • Cardivascular defect • Limb & Face malformation • Hairsutism

  30. Valsuroicacid • Diazepam • lorazepam • Lithium • Hydrochlorothiazide Category D drugs • Tetracycline • doxycycline • Streptomycin • Phenobarbital • Pentobarbital

  31. Category D drugs • Phenobarbital& Pentobarbital • paliative drug • Fetal malformation

  32. Category D drugs • Diazepam, Lorazepam , Chlorodiazepoxide • antianxiety drug • palate & lip clef specially in first 3 munth

  33. Category D drugs • Lithium ,Phenothiazine • Antiedepressive • CardioVascular defect

  34. Organic mercury Blindness, deaf, cerebral pulsy (c.p) • Lead mental retardation, death of fetus • Poly chlorinbiphenyil & Pentobarbital mental retardation, gingiva hyperplasia, exophthalmos, skull calcification, brown pigment in skin • Potassium iodide used as contrastment substance. mental retardation, goiter Chemical Agents(heavy metals)

  35. Physical Agents • Ionizing Radiation Acute high dose (over 250 rads) Microcephay,spinabifida,palate cleft, limb defect • Hyperthermia anencephaly,spina bifida, mental retardation, facial malformation, cardiac defect, limb defect

  36. Male-mediated Teratogenesis • Chromosomal defects & Mutation in germ cells • Environmental agent : transmission of paternal mediated toxicity through seminal fluid

  37. Prenatal Diagnosis • Ultrasonography • Maternal Serum Screening (AFP,hCG) AFP : Trisomy↓- NTD,GIT atresia,amniotic band↑ • Amniocentesis • Chorionic Villus Sampling (CVS)

  38. Fetal Therapy • Fetal Transfusion • Fetal Medical Treatment • Fetal Surgery • Stem Cell Transplantation and Gene Therapy Befor 18th week (activation of immune system)

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