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HUMAN GENETICS Disorders. Interpreting Pedigrees with Andrew Douch zInterpreting Pedigrees the Fast Way –Example 1(6:42)Interpreting Pedigrees the Fast.

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Presentation on theme: "HUMAN GENETICS Disorders. Interpreting Pedigrees with Andrew Douch zInterpreting Pedigrees the Fast Way –Example 1(6:42)Interpreting Pedigrees the Fast."— Presentation transcript:


2 Interpreting Pedigrees with Andrew Douch zInterpreting Pedigrees the Fast Way –Example 1(6:42)Interpreting Pedigrees the Fast Way zExample 2 (6:46)Example 2 z1. Is anyone with a phenotype different from parents? z2.Are there any girls with recessive phenotype who have a father or son with a dominant phenotype? zAutosomal Dominant X-linked dominant zAutosomal Recessive X-linked recessive

3 Autosomal Dominant: trait does not skip generations

4 Autosomal Recessive: tends to skip generations

5 X-linked dominant: both males and females affected does not skip generations zAffected sons have an affected mother

6 X-linked recessive: more males than females affected zSkips generations: affected sons from non-affected mothers

7 Testing for genetic disorders zUltrasound imaging-a sonogram made from passing high-frequency sound waves with a transducer through the abdomen z(least invasive)

8 Testing for genetic disorders zAmniocentesis-a small amount of amniotic fluid, which contains fetal tissues, is sampled zUse cells for karyotyping

9 Testing for genetic disorders zChorionic villus sampling (CVS)-take a sample of the placental tissue for chromosomal abnormalities zCan use cells for karyotyping

10 AUTOSOMAL RECESSIVE zAutosomes =, chromosomes #1- #22

11 Cystic Fibrosis-ff zIt causes the body to produce a thick, sticky mucus that clogs the lungs and digestive tract. On Chromosome 7 Autosomal recessive

12 One test is for salty skin CF salt test CF salt test zSalty skin (Mutations of the CFTR gene affect functioning of the chloride ion channels) zthin (do not digest well) zabnormal bowel movements zCFTR video (8:18) describe 6 mutation disfunctions for 2 pts Ex CrCFTR video

13 Cystic Fibrosis (cont.) zMost common fatal genetic disease in US today zMost common in Caucasians zSmall Child CR Treatment (thumping)Small Child CR Treatment zThumping Vest (1:24)Thumping Vest zLiving with CF (3:48)Living with CF Daily meds

14 Cystic Fibrosis zChromosome 7 zFF = no CF zFf = carrier zff = has CF z(recessive) zLife with CF (3:48) Life with CF

15 PKU zPhenylketonuria (PKU)

16 PKU on chromosome 12 recessive zLacks enzyme to break down the amino acid phenylalanine (found in milk)

17 PKU (cont.) zThe breakdown products can be harmful to developing nervous systems zLeads to mental retardation. zKate with PKU MovieKate with PKU Movie

18 PKU zChromosome 12 zPut on low protein diet zAvoid phenylalanine

19 TAY SACHS zResults in degeneration of the nervous system. zChromosome 15 zrecessive zHighest rate in Eastern European Jews, next Irish- Americans

20 Tay Sachs (cont) zLack enzyme to break down fat, accumulates in brain (poisons it) ztt zChromosome 15 zNOVA Online | Cracking the Code of Life | Watch the Program Here #3NOVA Online | Cracking the Code of Life | Watch the Program Here

21 Tay Sachs Disease is a fatal lipid storage disorder where a fatty substance (ganglioside) builds up in the nerve tissue and cells of the brain. This is caused by an insufficient enzyme called beta- hexosaminidase A that catalyzes the biodegration of gangliosides.

22 Tay-Sachs Symptoms Symptoms first appear at 4 to 6 months of age when an apparently healthy baby gradually stops smiling, crawling or turning over, loses its ability to grasp or reach out, and eventually becomes blind, paralyzed and unaware of its surroundings. Death usually occurs by age 4. Tay-Sachs PTTay-Sachs PT (1:52)

23 Albinism zInability to manufacture pigments (melanin) in skin and eyes zAutosomal recessive trait zChromosome 11

24 Albinism

25 Famous Albinos zAndy Warhol, a famous artist Rock musician Edgar Winter, an albino. The Twins in Matrix Reloaded

26 Is this an advantage or disadvantage?

27 zDifferent kinds of albinism zaffect chromosomes 1, 9, 10, 11, 15 and X (ocular albinism) Often rapid back and forth eye movement – lack of pigment in eyes.

28 Polar bears actually have black skin under all that white fur.

29 AUTOSOMAL DOMINANT on chromosomes 1-22

30 Sickle Cell Anemia zAutosomal dominant disease zChromosome #11 zRed blood cells collapse and clot blood vessels zFound in African- Americans

31 Sickle-Cells zNormal Red Blood Cells-like a donut zSickle-cells collapse, hard, clog vessels

32 Sickle-Cell Anemia zCodominant zSS = disease zAS = carrier (somewhat resistant to malaria) zAA =normal hemoglobin zLiving with SSALiving with SSA Plasmodium in blood - malaria

33 Sickle-Cell Complications 1.pain episodes 2.strokes 3.increased infections 4.leg ulcers 5.bone damage 6.yellow eyes or jaundice 7.early gallstones 8.lung blockage 9.kidney damage and loss of body water in urine 10.painful erections in men (priapism) 11.blood blockage in the spleen or liver (sequestration) 12.eye damage 13.low red blood cell counts (anemia) 14.delayed growth

34 Huntingtons Disease zWoody Guthries disease (folksinger 1960s) zAutosomal dominant zDoes not manifest itself until age 20s - 30s zH=dominant disease

35 What is the chance of a child of a Huntington Mother having Hungtingtons?

36 Huntingtons zChromosome 4 zAtrophy of brain zUncontrollable muscle spasms z40+ CAGs (build up protein clumps) zHuntington's Chorea Dance (5:33)Huntington's Chorea Dance Controls thinking, emotion, movement

37 Huntingtons zClumsiness zJaw clenching zLoss of coordination and balance zSlurred speech zSwallowing and/or eating difficulty zUncontrolled continual muscular contractions zWalking difficulty, stumbling zHostility/irritability Inability to take pleasure in life zLack of energy zperson with Huntington's also may exhibit psychotic behavior: zDelusion zHalluciations zInappropriate behavior (e.g., unprovoked aggression) zParanoia

38 Achondroplasia - Autosomal Dominant -chromosome 4 Achondroplasia: Genetic Causes Achondroplasia: Genetic Causes (2:40)

39 Achondroplasia zDwarfism zAchondroplasia: Genetics (2:20)Achondroplasia: Genetics zshort stature zDwarfism zshortening of limbs, ztrident hands zprominent forehead zAverage adult male height of 52 inches; average adult female height of 49 inches


41 FAQ zCan short-statured couples become the parents of average- size children? zAA=dead zAa=Achondroplasia zaa=normal A a AaAa

42 FAQ zCan short-statured couples become the parents of average- size children? zAA=dead zAa=Achondroplasia zaa=normal AAAa aa A a AaAa X

43 Alzheimer syndrome zWidespread nerve cell dysfunction and cell death in the brain zDementia (memory loss) zAlzheimer's Disease: Medical Update (1:39) Alzheimer's Disease: Medical Update zLife with AlzheimersLife with Alzheimers (3:56)

44 Alzheimer Syndrome zAutosomal Dominant zFound on Chromosome 1, or 10, or 14, or 19, or 21 zAPO4, is a cholesterol- carrying protein linked to development a protein that forms plaque in the brain zAlzheimer's neurology (1:01) Alzheimer's neurology zAlzheimers' Disease: NeurologyAlzheimers' Disease: Neurology

45 Brain Loss

46 Early or mild stage: zmemory loss, especially of recent events zdifficulty in recalling names and conversations zmisplacing objects zbecoming lost in familiar neighborhoods zrepeating stories and conversations zdifficulty in learning new information zpersonality changes zdecreased motivation and drive zeasily upset or anxious

47 Marfan Syndrome zautosomal dominant disorder zchromosome 15

48 Marfans: taller, pigeon chest Marfan's Video (2:45) Marfan's Spidery fingers, enlargement of aorta

49 Michael Phelps Does Not Have Marfans Clarence Holloway of Louisville does have Marfan's syndrome (had open-heart surgery ) X Gheorge Muresan 77 Extra Tall Athletes in their recruiting physical are tested for Marfans. Manute Bol did Died at age 47

50 Marfan Syndrome za connective tissue disorder zAffects skeleton, lungs, eyes, heart and blood vessels. zunusually long limbs zHigh arch palate zDebated if Abraham Lincoln has Marfans.

51 SEX-LINKED DISORDERS zOn X chromosome

52 Hemophilia- bleeders disease New Hemophilia Treatment (48 secs) New Hemophilia Treatment Living with HemophiliaLiving with Hemophilia (4:53)

53 Hemophilia blood tainted with AIDS z60 Minutes:Hemophiliacs Sue the Blood Donors Organizations60 Minutes:Hemophiliacs Sue the Blood Donors Organizations

54 Hemophilia passed by queen victoria zBlood does not clot normally zSex-linked recessive zMissing AHF (clotting factor in blood) zCzar Nicholas royal family

55 Royal Pedigree- Hemophilia

56 bleeders disease zX H X h = female carrier zX h X h = female hemo zX H Y = normal male zX h Y = hemo male

57 Color Blindness zinability to perceive differences between some of the colors that others can distinguish. zMore common in males zSex-linked (red and Green) on X chromosome What it's like being color-blind?What it's like being color-blind? (3:35)

58 Color Blindness z3 seconds to determine number Ishihara Test for Color Blindness

59 zThe individual with normal color vision will see a 5 revealed in the dot pattern. An individual with Red/Green (the most common) color blindness will see a 2 revealed in the dots. zAre You color blind? (2:26)Are You color blind?

60 Color blindness=cant tell certain colors zRecessive on X chromosome = c zX C X c = normal female (carrier) zX c Y = color-blind male

61 What numbers do you see?

62 Note: X and Y used

63 Need X and Y on Punnetts

64 Duchenne Muscular Dystrophy

65 MD zDuchenne Muscular Dystrophy zOn X m chromosome zWeakens and degenerates muscles zFound mostly in males zmutation in the dystrophin gene

66 DMD zabsence of dystrophin, a protein that helps keep muscle cells intact. -Leg muscles first. -Calves often enlarged. -Eventually this weakness spreads to the arms, neck, and other areas.

67 DMD zOnset ·Early childhood - about 2 to 6 years. z Symptoms · Generalized weakness of muscle zWasting affecting limb and trunk zDuchenne Timeline (5:43)Duchenne Timeline

68 DMD zSurvival rare beyond late twenties. zX-linked recessive (females are carriers ).

69 POLYGENIC DISORDERS zDetermination of disorder occurs on more than one chromosome

70 SPINA BIFIDA is a fault in the spinal column in which one or more vertebrae (the bones which form the backbone) fail to form properly, leaving a gap or split. A Snapshot of Spina BifidaA Snapshot of Spina Bifida (4:52)

71 Spina Bifida #6, #14 and others zGap in spinal column

72 Shunts often put in the brain to drain the fluid

73 Agent Orange zChildren with Spina Bifida whose parent was in contact with Agent Orange during the Vietnam War are compensated

74 Cleft Lip/Cleft Palate zA cleft is an opening in the lip, the roof of the mouth (hard palate) or the soft tissue in the back of the mouth (soft palate). #11, #17, #22

75 Clefts zBilateral Complete Cleft Lip/PalateBilateral Complete Cleft Lip/Palate Clefts occur more often among Asians and certain groups of American Indians than among whites. They occur less frequently among blacks.

76 Cleft lip/palate zAs you can imagine there are feeding problems z#11, #22, #17 – zPolygenic zUnilateral Cleft Lip Repair (9:15)Unilateral Cleft Lip Repair


78 Hypercholesterolemia polygenic dominant zis the presence of high levels of cholesterol in the blood. zlead to atherosclerosis (hardening of the arteries) zadditive effects of multiple genes (polygenic) yellowish patches consisting of cholesterol deposits above the eyelids.

79 Hypercholesterolemia

80 On Y chromosome SRY gene: male determining only on Y zTestes determining factor


82 NOTE: zIf you are born with no X chromosome- it is fatal zIf missing an autosome-it is fatal

83 X chromosome zSex-linked traits

84 Triple-X Syndrome ztriplo-X ztrisomy X zXXX syndrome z47,XXX aneuploidy There is usually no distinguishable difference to the naked eye between women with triple X and the rest of the female population.

85 Triple-X Syndrome zAlthough females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features. zMost females with triple X syndrome have normal sexual development and are able to conceive children.

86 Nondisjunction zChromosomes to segregate unevenly during meiosis zMistakes in MeiosisMistakes in Meiosis

87 Downs Syndrome zTrisomy 21 zExtra fold over eye zSluggish muscles zMental problems

88 Trisomy 21 Karyotype

89 Nondisjunction

90 Turners Syndrome Adults with Turner syndrome are short, averaging around four feet, eight inches in height. Flap in neck Small breasts

91 zBut girls with Turner syndrome don't start life as very short individuals - they become short over time-do not develop sexually

92 Turners Syndrome 45 X0

93 Kleinfelters 47 XXY

94 Kleinfelters -Testes are small -breast growth (gynaecomastia) -poorly developed secondary sexual characteristics.

95 Klinefelters zMen are sterile (no sperm).

96 Special Topics In Human Genetics

97 BARR BODIES zWhen a female is born one of her X chromosomes is inactivated = a Barr Body (early in embryonic development) zUsed to test femaledness at Olympics zSo there is not excess of X info in females

98 Calico Cat – X linked zOnly females have 3 colors (orange, black, white) zLooks like Pepper

99 Multiple colors in cats mostly in females

100 zGENETIC DISORDERS REFERENCE SHEET: Down Syndrome (Trisomy 21) Edward's Syndrome (Trisomy 18) Patau Syndrome (Trisomy 13) Klinefelter Syndrome (47, XXY) Turner Syndrome (45 XO) Metafemale (46XXX)-taller Autosomes (#1-22) so 44 if normal

101 Angelman Syndrome zDeletion of Chromosome 15 zIf inherited from FATHER zSymptoms: Short and obese, delayed development, frequent laughing

102 Angelman Syndrome

103 Prader-Willi Syndrome zDeletion is inherited from mothers chromosome 15 zHyperactive, chronic hunger, low muscle tone, obesity

104 Prader-Willi Syndrome –Before and after controlled eating

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