Transcript HUMAN GENETICS - Hudson City School District

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 7
FF = no CF
Ff = carrier
ff = has CF
(recessive)
PKU
Phenylketonuria (PKU)
PKU on chromosome 12
Lacks enzyme to break
down the amino acid
phenylalanine (found in
milk)
PKU (cont.)
The breakdown
products can be
harmful to
developing nervous
systems
Leads to mental
retardation.
Kate with PKU Movie
PKU
Chromosome 12
Put on low
protein diet
Avoid
phenylalanine
TAY SACHS
Highest rate in
Eastern
Results in
degeneration of European
Jews
the nervous
system.
Chromosome 15
Tay Sachs (cont)
 Lack enzyme to break
down fat, accumulates
in brain
 tt
 Chromosome 15
 NOVA Online |
Cracking the Code
of Life | Watch the
Program Here #3
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 occurs by
age 4.
Albinism
Inability to
manufacture
pigments (melanin)
in skin and eyes
Autosomal
recessive trait
Chromosome 11
(will be in movie)
Albinism
Andy Warhol, a famous
musician and filmaker (now
dead), was an albino.
Rock musician
Edgar Winter, an
albino.
Different kinds of albinism
affect chromosomes 1, 9, 10,
11, 15 and X.
Often rapid back and forth eye
movement – lack of pigment in eyes.
AUTOSOMAL DOMINANT
Sickle Cell Anemia
Found in AfricanAutosomal
Americans
dominant
disease -#11
Red blood cells
collapse and clot
blood vessels
Sickle-Cells
Normal Red
Blood Cells-like
a donut
Sickle-cells
collapse, hard,
clog vessels
Sickle-Cell Anemia
Codominant
SS = disease
AS = carrier (somewhat resistant to
malaria)
AA =normal hemoglobin
Sickle Cell Disease - What Causes
Sickle Cell Disease Video About.com
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
Huntington’s Disease
Woody Guthrie’s
disease (folksinger
1960’s)
Autosomal dominant
Does not manifest
itself until age 20’s 30’s
H=dominant disease
Huntington’s
Chromosome 4
Atrophy of brain
Uncontrollable
muscle spasms

Huntington's Disease Information - HOPES - HOPES Video
Player (SWF)
 (segment 4)

New Treatment for Huntington's Disease - Health Videos – redOrbit
40+ CAG’s

HowStuffWorks Videos "Treating
Huntington's Disease"
Huntington’s














Clumsiness
Jaw clenching
Loss of coordination and balance
Slurred speech
Swallowing and/or eating difficulty
Uncontrolled continual muscular contractions
Walking difficulty, stumbling
Hostility/irritability
Inability to take pleasure in life
Lack of energy
person with Huntington's also may exhibit psychotic behavior:
Delusion
Halluciations
Inappropriate behavior (e.g., unprovoked aggression)
Paranoia
Achondroplasia
-Autosomal
Dominant
-chromosome 4
Achondroplasia
Dwarfism
Average adult male
height of 52 inches;
average adult female
height of 49 inches
short stature
Dwarfism
shortening of limbs,
trident hands
prominent forehead,
FAQ
Can short-statured
couples become the
parents of averagesize children?
AA=dead
Aa=Achondroplasia
aa=normal
A
A
a
a
FAQ
Can short-statured
couples become the
parents of averagesize children?
AA=dead
Aa=Achondroplasia
aa=normal
A
a
A AA
Aa
Aa
aa
a
Alzheimer syndrome
Widespread nerve
cell dysfunction and
cell death,
neurotransmitter
deficiencies
Dementia
Alzheimer Syndrome
Autosomal Dominant
Found on
Chromosome 1, or
10, or 14, or 19, or 21
APO4, is a cholesterolcarrying 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
autosomal
dominant
disorder
 chromosome 15
(will be in movie)
Marfan’s: taller, pigeon
chest
Spidery fingers, enlargement of aorta
Marfan Syndrome
a connective tissue
disorder,
Affects skeleton,
lungs, eyes, heart
and blood vessels.
unusually long
limbs
affected Abraham
Lincoln.
SEX-LINKED DISORDERS
On X
chromosome
Hemophilia- “bleeder’s disease”
Hemophilia passed by
queen victoria
Blood does not Czar Nicholas
clot normally
royal family
Sex-linked
recessive
Missing AHF
(clotting
factor in blood)
Royal PedigreeHemophilia
“bleeder’s disease”
XHXh = female
carrier
XhXh = female
hemo
XHY = normal
male
XhY = hemo male
Hemophilia Video
(from WHF)
Color Blindness
inability to perceive differences
between some of the colors that
others can distinguish.
More common in males
Sex-linked (red and
Green) on
X chromosome
Color Blindness
3 seconds to
determine number
Ishihara Test for Color
Blindness
Ishihara
The individual
with normal color Test for
vision will see a 5 Color
revealed in the
Blindness
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 Dystrophy
On Xm chromosome
Weakens and degenerates
muscles
Found mostly in males
DMD
absence of dystrophin, a protein that
helps keep muscle cells intact.
Leg muscles first.
Calves often
enlarged.
DMD
Onset ·Early childhood about 2 to 6 years.
 Symptoms ·
Generalized
weakness of muscle
Wasting affecting
limb and trunk
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 others
Gap 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
#11, #17, #22
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).
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
NOTE:
If you are born with no “X”
chromosome- it is fatal
If missing an autosome-it is
fatal
X chromosome
Sex-linked traits
Triple-X Syndrome
triplo-X
trisomy X
XXX syndrome
47,XXX aneuploidy
There is usually no distinguishable
difference to the naked eye
between women with triple X
and the rest of the female population.
Triple-X Syndrome
Although females with this condition may
be taller than average, this chromosomal
change typically causes no unusual
physical features.
Most females with triple X syndrome have
normal sexual development and are able
to conceive children.
Nondisjunction
Chromosomes
to segregate
unevenly
during meiosis
Mistakes in
Meiosis
Down’s Syndrome
Trisomy 21
Extra fold over
eye
Sluggish
muscles
Mental
problems
Trisomy 21 Karyotype
Nondisjunction
Turner’s Syndrome
Adults with Turner syndrome are short,
averaging around four feet, eight inches in
height.
Flap in neck
Small breasts
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
-breast growth (gynaecomastia)
-poorly developed secondary sexual
characteristics.
Klinefelter’s
Men are sterile (no sperm).
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 – X linked
Only females
have 3 colors
(orange,
black, white)
Looks like
“Pepper”
Multiple colors in cats mostly
in females
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 15
If 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