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What is PKU?
• PHENYLKETONURIA (PKU)
– PAH gene on long arm of chromosome 12 is
absent/reduced
– Excess phenylalanine interferes with brain
development
• Autosomal recessive disorder
1:10,000-15,000 births
• Effects: retardation, seizures, destructive,
restlessness
What is Hemophilia?
• AKA: Factor VIII deficiency
• Blood clotting disorder
usually affecting males
– 1 in 5,000
• Abnormal protein “Factor
VIII” created
– Factor VIII necessary for
blood clotting
– Clotting takes longer
• Severity varies based on
amount of Factor VIII
produced
• Sex-linked disorder (found
on X chromosome)
Treatments
• Factor VIII Replacement:
– Intravenous injections of
Factor VIII
– Causes proteins to help
clotting
• Joint Replacement
– Knee, hip, ankle replacement
if arthritis is severe
• Regular exercise for strong
muscles to protect the weak
joints
Alcohol Related Disorders
Two categories:
1) Alcohol Abuse: pattern of constant intoxication,
daily, blackouts, unsuccessful attempts to stop
2) Alcohol Dependence (alcoholism): Alcohol abuse
and increased tolerance or withdrawal symptoms
– Becomes evident within first 5 years of drinking
Inheritance
• Alcoholism often found in several generations of
families
• Multiple genes probably contribute
– Genes & enzymes affect how alcohol is metabolized
• Familial Alcoholism
– Positive family history
– Early onset (in the 30s)
– More severe
The genetics staff explains to Martha that at age 40,
the risk of delivering a child with Down syndrome is
about 1 in 110.
Martha’s drinking is discussed again in light of her
pregnancy. Fetal alcohol syndrome is reviewed, and
Martha is strongly advised to stop drinking for the
duration of her pregnancy.
Familial Hypercholesterolemia (FH)
• Cholesterol basics
– LDL: bad cholesterol
– HDL: good cholesterol
• Gene on chromosome
#19, makes body unable
to remove LDL
• Cholesterol levels
unregulated
– LDL builds up
• Potentially fatal
• Autosomal dominant
The human genome contains about 3 billion base pairs, of which only about 3%
constitute expressed genes.
The non coding regions of the genome vary tremendously and may differ between
individuals by changes in single base pairs of different numbers of repeats of a particular
base pair sequence.
DNA goes through a form of “digestion”, where regions of DNA are cut by restriction
enzymes, which recognize specific sequences. This leaves various lengths of fragments
called restriction fragment length polymorphisms (RFLPs).
For every individual, half of the DNA is from mom, half from dad….
So, for a given region of DNA, one fragment length is inherited from mom and one from
dad.
We use RFLPs as a form of paternal testing, which sizes the fragments.
Fetal effects of smoking
• ~25% pregnant woman smoke
• Blood vessels constricted
– Reduced blood flow
• Low birth weight
• 30% higher death rates
• More prone to infections
B-Thalassemia
• Gene disorder: Autosomal
recessive
• Red blood cell deficiency
• Common ethnicities:
– African decent
– Mediterranean decent
– SE Asian decent
• Early heart & spleen disease
• Treatments: Blood
transfusions
Cystic Fibrosis
• Autosomal recessive
• Faulty gene causes mucus to
build up in lungs,
– Become infected
• Lung damage usually causes
early death
• Treatments: Transplants, chest
thumping, antibiotics
Huntington’s Disease
•
•
•
•
Autosomal dominant
Death of nerve cells in brain
Signs show around middle age
Due to defective (misshaped)
gene