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HUMAN GENETICS
Disorders
AUTOSOMAL RECESSIVE
Autosomes = , chromosomes #1- #22
Cystic Fibrosis-ff
It causes the body to produce a thick, sticky mucus that clogs the lungs and digestive tract.
Cystic Fibrosis (cont.)
Most common fatal genetic disease in US today
Most common in Caucasians
Cystic Fibrosis Movie
Cystic Fibrosis
Chromosome 7FF = no CFFf = carrierff = has CF(recessive)
PKU on chromosome 12
Lacks enzyme to break down the amino acid phenylalanine (found in milk)
Phenylketonuria (PKU)
PKU (cont.)
The breakdown products can be harmful to developing nervous systems
Leads to mental retardation. Kate with PKU Movie
PKU
PKUChromosome 12
Put on low protein diet
Avoid phenylalanine
TAY SACHS
Results in degeneration of the nervous system.
Chromosome 15
Highest rate in Eastern European Jews
Tay Sachs (cont)
Lack enzyme to break down fat, accumulates in brain
tt Chromosome 15 NOVA Online | Cracki
ng the Code of Life | Watch the Program Here #3
Tay-Sachs SymptomsSymptoms 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 eventuallybecomes blind, paralyzed and unaware of its surroundings. Death occurs by age 4.
Albinism
Inability to manufacture pigments (melanin) in skin and eyes
Autosomal recessive trait
Chromosome 11 (will be in movie)
AUTOSOMAL DOMINANT
Sickle Cell Anemia
Autosomal dominant disease -#11
Red blood cells collapse and clot blood vessels
Found in African-Americans
Sickle-Cells
Normal Red Blood Cells-like a donut
Sickle-cells collapse, hard, clog vessels
Sickle-Cell Anemia
CodominantSS = diseaseAS = carrier (somewhat resistant to
malaria)AA =normal hemoglobinSickle Cell Disease - What Causes Sickle
Cell Disease Video - About.com
Sickle-Cell Complications1.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
Huntington’s Disease
Woody Guthrie’s disease (folksinger 1960’s)
Autosomal dominantDoes not manifest
itself until age 20’s - 30’s
H=dominant disease#4
Huntington’sChromosome 4Atrophy of brainUncontrollable
muscle spasms Huntington's Disease Information - HO
PES - HOPES Video Player (SWF) (segment 4) New Treatment for Huntington's Disea
se - Health Videos - redOrbit
Achondroplasia
Autosomal Dominantchromosome 4
Achondroplasia
Dwarfism
short statureDwarfismshortening of limbs, trident handsprominent forehead,
Average adult male height of 52 inches; average adult female height of 49 inches
FAQ
Can short-statured couples become the parents of average-size children?
AA=deadAa=Achondroplasiaaa=normal
A a
A
a
FAQ
Can short-statured couples become the parents of average-size children?
AA=deadAa=Achondroplasiaaa=normal
AA Aa
Aa aa
A a
A
a
Alzheimer syndrome
Widespread nerve cell dysfunction and cell death, neurotransmitter deficiencies
Dementia HowStuffWorks
Videos "Treating Huntington's Disease"
Alzheimer Syndrome
Autosomal DominantFound on Chromosome 1, or
10, or 14, or 19, or 21APO4, is a cholesterol-carrying protein
linked to development a protein that forms plaque in the brain
Brain Loss
Early or mild stage:
memory loss, especially of recent events difficulty in recalling names and conversations misplacing objects becoming lost in familiar neighborhoods repeating stories and conversations difficulty in learning new information personality changes decreased motivation and drive easily upset or anxious
Marfan Syndrome
a connective tissue
disorder, Affects skeleton,
lungs, eyes, heart and blood vessels.
unusually long limbs
affected Abraham Lincoln.
Marfan Syndrome
autosomal dominant disorder
chromosome 15(will be in movie)
SEX-LINKED DISORDERS
On X chromosome
Hemophilia
Hemophilia
Blood does not clot normally
Sex-linked recessive
Missing AHF (clotting factor in blood)
Czar Nicholas royal family
Royal Pedigree-Hemophilia
“bleeder’s disease”
XHXh = female carrier
XhXh = female hemo
XHY = normal male
XhY = hemo male
Color Blindness
More common in males
Sex-linked (red and green on X chromosome)
Blue is on an autosome
Ishihara Test for Color Blindness
Ishihara Test for Color Blindness
The 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.
Color blindness=can’t tell certain colors
Recessive on X chromosome = c
XCXc = normal female (carrier)
XcY = color-blind
male
What numbers do you see?
Note: X and Y used
Need X and Y on Punnetts
Duchenne Muscular Dystrophy
MD
Duchenne Muscular DystrophyOn Xm chromosomeWeakens and degenerates
musclesFound mostly in males
DMD
Onset ·Early childhood - about 2 to 6 years.
Symptoms · Generalized weakness of muscle
Wasting affecting limb and trunk
Leg muscles first. Calves often enlarged.
DMD
Survival rare beyond late twenties.
X-linked recessive (females are carriers).
POLYGENIC DISORDERS
Determination of disorder occurs on more than one chromosome
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.
Spina Bifida
#6, #14 and othersGap in spinal
column
Shunts often put in the brain to drain the fluid
Agent Orange
Children with Spina Bifida whose parent was in contact with Agent Orange during the Vietnam War are compensated
Cleft Lip/Cleft Palate
A 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
Clefts
Clefts occur more often among Asians and certain groups of American Indians than among whites. They occur less frequently among blacks.
Cleft lip/palate
As you can imagine there are feeding problems
#11, #22, #17 –polygenic
On Y chromosome
Testes determining factor
Nondisjunction
Chromosomes to segregate unevenly during meiosis
Mistakes in Meiosis
Down’s Syndrome
Trisomy 21Extra fold over
eyeSluggish
musclesMental
problems
Trisomy 21 Karyotype
Nondisjunction
Turner’s Syndrome
Adults with Turner syndrome are short, averaging around four feet, eight inches in height.
But girls with Turner syndrome don't start life as very short individuals - they become short over time-do not develop sexually
Turner’s Syndrome 45 X0
Kleinfelter’s 47 XXY
Kleinfelter’s
Testes are small and fail to produce normal levels of testosterone which leads to breast growth (gynaecomastia) in about 40% of cases and to poorlydeveloped secondary sexual characteristics.
Klinefelter’s
Men are sterile (no sperm).
NOTE:
If you are born with no “X” chromosome- it is fatal
If missing an autosome-it is fatal
Special Topics In Human Genetics
BARR BODIES
When a female is born one of her X chromosomes is inactivated = a Barr Body (early in embryonic development)
Used to test femaledness at Olympics
So there is not excess of X info in females
Calico Cat
Only females have 3 colors (orange, black, white)
Looks like “Pepper”
GENETIC 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
Angelman Syndrome
Deletion of Chromosome 15If inherited from FATHER Symptoms: Short and obese, delayed
development, frequent laughing
Angelman Syndrome
Prader-Willi Syndrome
Deletion is inherited from mother’s chromosome 15
Hyperactive, chronic hunger, low muscle tone, obesity
Prader-Willi Syndrome
–Before and after controlled eating