Some Genetic Disorders
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Transcript of Some Genetic Disorders
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.
Huntington’s Disease
• Dominant disorder
• Symptoms:– Breakdown of brain and nerve tissue– Irritability– Loss of coordination and balance– Trouble speaking and swallowing– Death
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.
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
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
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
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
Cystic Fibrosis
• Other Important Info.:– Life expectancy: 30 yrs
– Most common genetic disease in Caucasians
– Treatments: physical therapy and gene therapy
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
Tay-Sachs Disease
• Recessive disorder
• Symptoms:– Lipids buildup in central nervous system– Loss of motor skills– Blindness– Paralysis– Death
Tay-Sachs Disease
Other Important Info:• Life expectancy 5 yrs• Most common in
Jewish and Amish people
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
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
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.
Phenylketonuria (PKU)
Practice Problem:
A woman has PKU. A man is completely normal. What is the chance of their child having PKU?
Answer: _____% chance
Albinism
• Recessive disorder
• Symptoms:– Causes no or little pigment (melanin) in eyes,
skin, and hair• Blue eyes
• Pale skin
• Light hair