Transcript Human Genetic Diseases

Human Genetic Diseases
(Simple Dominance Inheritance)
Dominant Human Diseases
• Only have to inherit it from one parent
• Having disease is dominant to not having
disease
• If child has it, a parent must have it also
Huntington’s Disease
• Inheritance Pattern: Dominant
• Symptoms:
– Breakdown of brain tissue
– Irritability, forgetfulness, loss of coordination
Huntington’s Disease (cont.)
• Other Important Information:
– Rare but lethal
– Symptoms show up between 30-50 years old
• May have already had kids
Catfish Hunter
Woody Guthrie
Example Problem:
• A man who is homozygous for HD and a
woman that does not have HD have a
child. What is the chance that the child
will have HD?
Achondroplasia
• Dwarfism
• Inheritance Pattern: Dominant
• Symptoms:
– Short arms and legs
– Normal skull and torso
Achondroplasia (cont.)
• Other Important
Information:
– Inhibits bone growth
(cartilage slow to turn
to bone)
– Most have normal life
expectancy
Example Problem:
• What is the chance of 2 dwarfs that are
heterozygous for the disease to have a
child that is normal sized?
Recessive Human Diseases
• Not having disease is dominant over having the
disease
• Have to inherit the recessive allele from both
parents (i.e. 2 little letters)
• A person can be a CARRIER (heterozygous) for
the disease and not show symptoms
• If two carriers have a child, the child has a 25%
chance of having the disease
• A child can have it without either parent having it
Cystic Fibrosis
• Inheritance Pattern:
Recessive
• Symptoms:
– Overproduction and buildup of mucus in lungs and
digestive tract
– Difficulty breathing
– Salty skin
Cystic Fibrosis (cont.)
• Other Important Information:
– Avg. life expectancy 30 – 40 years
– Most common genetic disease in white
Americans
– Treatment: physical therapy, gene therapy,
special diet
Gene Therapy
Example Problem:
• A child’s mom is completely normal. His
dad is a carrier for CF. What is the
chance that the child will also be a carrier?
Other Weird Genetic “Conditions”
Vadoma Tribe – Zimbabwe
- Ostrich-toed (ectodactyly)
Blue people of Troublesome Creek
-Result from lack of an enzyme
-Causes abnormal hemoglobin
Old Slides
Phenylketonuria (PKU)
• Inheritance Pattern: Recessive
• Symptoms:
– a.a. phenylalanine accumulates in body and
damages CNS → brain damage
– Now can be detected at birth before brain
damage occurs
PKU (cont.)
• Other Important Information:
– Treatment:
• Babies – diet low in milk until brain is fully
developed
• Pregnant women – limit milk, diet foods, protein
Example Problem:
• A woman has PKU. A man is completely
normal. What is the chance of their child
having PKU?