Genetic disorders
Caused by:
~ _________________________
________________________
Or
~ _________________________
_________________________
Altered Chromosomes

# can change due to _________________
__________________________________
structure can change _______________
__________________________________
__________________________________
( Remember: chromosomes are DNA
wrapped around histones. When the DNA
is altered the structure changes)

________
-
&
_________
Substance that can cause 1- _______________ Mutationreproductive cells (sperm &
a mutation
egg)
- Ex- UV Light
2- __________ Mutation- body
- X-Rays
cells (types of Cancer)
- Radiation
- Viruses
- Tobacco
Types of structural
Mutations
1- ________________- piece
of chromosome is lost
(Cri-du-Chat or PraderWilli Syndrome)
2- __________________piece breaks off &
reattaches upside down
3- ___________________piece breaks off and
attaches to a different
chromosome
4- ____________________- removal of
a single DNA nucleotide
(one nitrogen base is substituted with another)
Example** Original - The fat cat ate the wee rat.
** Point Mutation - The fat hat ate the wee rat.
Carcinogen- mutation that may cause cancer
Cri du Chat Syndrome: ___________
Characteristics
- High pitched mewing
cry as an infant
- Slant of the eyes
- Mental retardation
- _________________
__________________
__________________
Prader –Willi Syndrome: _____________
Characteristics
- Infants are weak- sucking
reflex is poor & feeding is
difficult
- _______________________
______________________
- Children become extremely
obese
- ______________________
- Short stature
- Poor sexual development
- Behavioral issues
Changes in the Chromosome
Number
_______________________- chromosomes fail to
separate during Meiosis; will cause a lack of a
chromosomes or will give you an extra chromosome
2 Types
1- _______________- lack a chromosome
_________________________________
- _______ chromosomes = XO
-________________________
- webbed neck - short
- swelling at wrists & ankles
- ______________________________
- 2. Trisomy- ___________________________
- ex: __________________(Trisomy 21)- males &
females, decreased muscle tone, slanting eyes, small mouth
with protruding tongue, mental retardation
Types of Nondisjunction
Klinefelter’s Syndrome (______________________)_____________________, tall (long legs with short trunk),
infertile, low IQ, enlarged breast tissue (a type of Trisomy)
Detecting Human Genetic Disorders
Genetic screening- examine a
person’s genetic make-up
(Karyotype, Blood tests)
2 methods:
1- ____________________amniotic fluid withdrawal
2- ____________________
(CVS)- take a sample of villi
(_____________________
_____________________)
**Both produce Karyotype**
Detecting Human Genetic Disorders
Advantage of both: - Physicians can detect more
than _________________________________
 Disadvantage of Amniocentesis: most
conditions are incurable and the results
____________________________________
(abortion at this time is very difficult)
 Disadvantage of CVS: __________________
________________________or miscarriage
but it comes back b/4 1st trimester is over

Genetic Traits & Disorders
Genetic Disorder- disease or set
of conditions that have a
genetic basis.
1- Single Allele Trait- 1 allele
controls the trait
A) ____________________:
Ex: Huntington’s disease,
Achondroplasia (dwarfism),
Cataracts, Polydactyl)
B) _____________________:
Ex: albinism, cystic fibrosis, sickle
cell anemia, PKU, Marfan
Genetic Traits & Disorders
2.- ______________________
3 or more alleles of the same
gene code for a single trait
Ex- Blood Groups (A, B, O)
3- ______________________traits that are controlled by
many genes (Skin, Hair &
Eye color, Height, Foot size)
4- ______________________phenotype depends on gender
and hormones (Baldness)
Genetic Traits & Disorders
5- __________________found only one the X
Chromosome
ExamplesColorblindness,
Fragile- X, Hemophilia,
Muscular Dystrophy,
Ichthyosis simplex (Scaly
skin)
Heterozygous advantage
Malaria and sickle cell
anemia
_______________
 _______________
 _______________
 _______________
 _______________
