1. Some Genetic Disorders

2. Genetic Disorders
All of the disorders in this presentation are autosomal. This means they NOT located on the sex chromosomes, but on the other chromosomes.
Dominant (big letters) disorders show up with just one allele present from one parent.
Recessive (little letters) disorders only show up when two alleles are present. Parents don’t have to have it for a child to have it.

3. Huntington’s Disease Dominant disorder Symptoms:
Breakdown of brain and nerve tissue
Irritability
Loss of coordination and balance
Trouble speaking and swallowing
Death

4. Huntington’s Disease Other Important Info.: Rare, but lethal
Symptoms show up between ages 30 – 50
Affected individuals may have already had children and passed it on to them before they knew they had HD.
Very similar to Parkinson’s Disease.

5. Huntington’s Disease Practice 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?
Answer: ______ % chance

6. Achondroplasia (Dwarfism)
Dominant disorder
Symptoms:
Short arms, short legs, but normal sized skull and torso (Disproportionate dwarfism)
Other Important Info.:
Inhibits bone growth- cartilage is slow to turn to bone
Have normal intellectual capacity

7. Achondroplasia (Dwarfism)
“Big World Little People” Family

8. Achondroplasia (Dwarfism)
Practice Problem:
What is the chance of 2 dwards that are heterozygous for the disease to have a normal-sized child?
Answer: _____% chance

9. Cystic Fibrosis Recessive disorder Symptoms:
Overproduction of/and buildup of mucus in lungs and digestive tract
Salty skin (very salty sweat)
Difficulty breathing
Chronic coughing and wheezing
Inflammation of lungs

10. Cystic Fibrosis Other Important Info.: Life expectancy: 30 yrs
Most common genetic disease in Caucasians
Treatments: physical therapy and gene therapy

11. Cystic Fibrosis Practice 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?
Answer: _____% chance

12. Tay-Sachs Disease Recessive disorder Symptoms:
Lipids buildup in central nervous system
Loss of motor skills
Blindness
Paralysis
Death

13. Tay-Sachs Disease Other Important Info: Life expectancy 5 yrs
Most common in Jewish and Amish people

14. Tay-Sachs Disease Practice Problem:
Two carriers for Tay-Sachs have a child. What is the chance that the child will have Tay-Sachs?
Answer: _____% chance

15. Phenylketonuria (PKU)
Recessive disorder
Symptoms:
Phenlyalanine (an amino acid) builds up in body
Damages central nervous system
Causes mental retardation, seizures, tremors, social/behavior problems
Stunted growth
Hyperactivity
Vomiting and bad breath

16. Phenylketonuria (PKU)
Other Important Info.:
Treatment:
Babies receive a special non-milk formula
Affected individuals should eat a special diet, limited in protein-rich foods and avoid artificial sweetners.

17. Phenylketonuria (PKU)
Practice Problem:
A woman has PKU. A man is completely normal. What is the chance of their child having PKU?
Answer: _____% chance

18. Albinism Recessive disorder Symptoms:
Causes no or little pigment (melanin) in eyes, skin, and hair
Blue eyes
Pale skin
Light hair

19. Albinism Other Important Info.: Sensitive to sun exposure
Vision is impaired

20. Answer: ______% chance
Albinism
Practice Problem:
Is it possible for 2 albino people to have a child with normal pigment?
Answer: ______% chance