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) “Big World Little People” Family

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

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

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