Download Genetic disorder/testing PPT

Ultrasound:
Machine
Using sound waves to look at physical
features of the developing fetus
including size, anatomy, number of
appendages/parts, sex, and heartbeat.
Amniocentesis
• Amniocentesis is a
diagnostic prenatal test
that allows doctors to
collect information
regarding the baby’s
health by gathering
amniotic fluid that has
cells sloughed off from
the growing fetus. The
cells then can be
analyzed for their DNA
through gene testing and
karyotyping.
Chronic villi sampling
Also tests
cellular material.
Causes
spontaneous
abortions
sometimes, but
can get more
information.
A karyotype is chart of someone’s
chromosomes. The chromosomes
are organized by size, large to
small.
This arrangement helps scientists
be able to identify genetic
disorders caused by chromosome
alterations.
To be able to make a karyotype
scientists take a picture of your
chromosomes , cut them out and
match them depending on size,
banding pattern and centromere
position.
This is an examples
of a karyotype. In
this example it is
easy to see that this
person has
Klinefelter syndrome
due to the extra Y sex
chromosome.
Different dyes and computers make
karyotyping easier today.
Gene Testing
• Since the Human Genome Project identified
where genes are located and what they do, we
now have developed many tests to examine
what form of the gene a person has. This
testing can be done on embryonic stem cells
early in the development or for invitro fertilization
OR it can be done on cells in amniotic fluid.
• Specific to one gene/protein, but many tests can
be run on one sample at the same time. DNA
chips are being developed.
CYSTIC FIBROSIS: Recessive
• Mutation in the gene coding for a
transmembrane protein in the lungs.
• Due to loss of chromosome, located on
chromosome 7.
• Recessive
What happens
•
•
•
•
Symptoms occur throughout the whole body
Newborns: Delayed growth
Bowels: Severe constipation
Lungs: Mucus build up
More on Cystic Fibrosis
•
•
•
•
Blood tests look for variations of the gene in CFTR.
Exercising
Medicines (antibiotics, anti-inflammatory, bronchodilators)
Lung transplants for critical conditions
Cystic Fibrosis is common in the Caucasian population in the
US.
1 in 2,500-3,500 Caucasian newborns
1 in 17,000 African Americans
1 in 31,000 Asian Americans
Other recessive disorders
• Tay Sachs: can’t break down fats accumulating
in the brain due to faulty enzyme (baby dies
early), common in certain Jewish communities
• PKU: can’t break down phenylalanine amino
acid, so low protein diet is needed.
• Sickle cell anemia: common in groups with
ancestory in low latitude (tropics) as
heterozygous condition protects from Malaria.
African Americans most likely group in USA.
Down Syndrome: trisomy 21
• Chromosome 21
• Nondisjunction
• Trisomy 21
More on Down Syndrome
• Physical
• Mental
Hemophilia: sex-linked recessive
Recessive
F8 genes- Hemophilia A
F9 genes- Hemophilia B
Lack of proteinFactor VIII, IX
Hemophilia
Easy Bruising
Extended Bleeding
Tight joints
Swelling
BRCA 1 and 2: predisposition to
Breast Cancer
• 5%-10% cases hereditary
• Caused by mutations on chromosomes
13/17 ( genes BRCA1 and BRCA2)
• What are my choices
Frequent mammograms and breast exams
Surgery to remove a tumor or the whole breast
Chemotherapy
Hormone therapy
Klinefelter's Syndrome
(trisomy XXY)
&
Turner’s Syndrome
(monosomy XO)
Klinefelters: male with female secondary sex
characteristics sometimes: others have very little
symptoms
Turner’s syndrome: very serious female disorder with
webbing, short stature, lack of development.
Huntingdon’s disease: dominant
disorder
First shows after
35 years old.
SYMPTOMS
35-44 years old
Cognitive and Psychiatric
Atrophy
Neurons
Depression and Anxiety
Chorea