Ch 11 NOTES #7 Genetic diseases

GENETIC DISORDERS – any disease that is caused by a problem with a person’s chromosomes/ genes on them

3 MAIN KINDS OF GENETIC DISORDERS Single gene inheritance - problem in 1 gene on the chromosome * over 6,000 known * 1 out of every 200 births On the X or Y chromosome – sex-linked On the 22 pairs of non-sex chromosomes - autosomal

CAUSES: a. INHERITED - passed down from parents * may show up later in life

b. ACQUIRED MUTATION – physical change to a gene from - radiation, chemicals, pollution Only mutations in GAMETES can be passed on to children

SOME SINGLE GENE MUTATIONS

1. Cystic Fibrosis Body produces extra mucus in lungs Hard time breathing http://www.youtube.com/watch?v=kjvkrbsBGqI

2. Marfan Arms and legs grow extra long 15

3. Huntington’s nerve cells in the brain waste away that control muscle movement Person shakes uncontrollably Some of the symptoms include: poor memory, depression and/or mood swings, lack of coordination, twitching or other uncontrolled movements, and difficulty walking, speaking, and/or swallowing. In the late stages of the disease, a person will need help doing even simple tasks, such as getting dressed. http://www.youtube.com/watch?v=JzAPh2v-SCQ

4. Sickle Cell Blood is not circular Causes clots, lots of pain, strokes Mostly in African Americans

5. Albinism No gene for making melanin (color in eyes, hair, and skin) Can burn in the sun easily

6. Progeria Body ages really fast – die by 25 Kids below are under age 17!

https://www.youtube.com/watch?v=Fekab9Pu2us If you want to see a kid with progeria, click link

7. SCIDS Kids born without an immune system to fight off germs Usually die by age 7

DONE WITH EXAMPLES

2. Multifactorial CAUSE: Many genes + often environment (how you live) EXAMPLES: Heart disease High blood pressure Obesity Diabetes Cancers – EX: Breast cancer - chromosomes 6, 11, 13, 14, 15, 17, and 22 Arthritis Symptoms usually appear in the first few months of life. Because the immune system cannot protect the baby's body, babies with the disorder tend to get one infection after another. Some of these bacterial infections may be life-threatening, including pneumonia (lung infection), meningitis (brain infection), and sepsis (blood infection).

EXPLANATION OF MULTIFACTORIAL READ: You may have a gene for high blood pressure (it runs in your family) BUT… if you eat right, don’t get overweight, and exercise often then it may not start to show up in you.

3. Chromosome abnormalities - Too many or not enough chromosomes We are supposed to have 46 chromosomes, but some humans can survive with 1 more or 1 less BUT it makes big problems

NONDISJUNCTION - chromosomes don’t separate right during meiosis CAUSE: NONDISJUNCTION - chromosomes don’t separate right during meiosis Was supposed to be 2 chromosomes in each egg or sperm

TRISOMY – set of 3 (47) MONOSOMY – set only 1 (45) LOOK – an extra chromosome here LOOK – chromosome missing here

EXAMPLES:

1. Down’s Syndrome Trisomy 21 – an extra chromosome #21 Mental retardation Down syndrome is the most common genetic disorder caused by a chromosomal abnormality. It affects 1 out of every 800 to 1,000 babies.

2. TURNERS SYNDROME Instead of being a girl “XX” They are just One “X” Turner Syndrome affects 60,000 girls and women in the United States. This disorder occurs in 1 in 2000 to 1 in 2500 live births, with about 800 new cases diagnosed each year. Symptoms include short stature and lack of ovarian development. Other features, such as webbed neck, arms that turn out slightly at the elbow, and a low hairline in the back of the head are sometimes seen. Instead of being a girl “XX” They are just One “X” Women with Turner syndrome appear to have a stocky appearance, arms that turn out slightly at the elbow, a receding lower jaw, a short webbed neck, and low hairline at the back of the neck. Other medical symptoms include: lymphedema (swelling of hands and feet), heart and/or kidney defects, high blood pressure, and infertility (inability to have children). Interesting facts about Turner syndrome Turner Syndrome affects 60,000 females in the United States. This disorder is seen in 1 of every 2000 to 2500 babies born, with about 800 new cases diagnosed each year.

3. Edward’s Syndrome Trisomy 18 - An extra #18 Feeding difficulties Breathing difficulties Mental retardation Undescended testicles in males Prominent back portion of the head Small head (microcephaly) Low-set, Abnormally small jaw (micrognathia) Cleft lip/Cleft palate

3. Kleinfelter’s Male with female characteristics They are XXY Many people with this disorder have no idea they have it until they hit puberty or try to have children. At puberty, men with this syndrome often develop more breast tissue than normal, have a less muscular body, and grow very little facial or body hair. When men with Klinefelter syndrome try to have children, most discover that they are sterile because they cannot produce sperm. Klinefelter syndrome is one of the most common genetic abnormalities. It affects between 1 in 500 and 1 in 1,000 males.

4. Patau Syndrome Trisomy 13 - extra #13 mental & motor retardation polydactyly (extra digits) low-set ears heart defects structural eye defects cleft palate or hare lip

5. Cri-du-chat http://www.youtube.com/watch?v=TYQrzFABQHQ feeding problems because of difficulty swallowing and sucking; low birth weight and poor growth; severe cognitive, speech, and motor delays; behavioral problems such as hyperactivity, aggression, tantrums, and repetitive movements; unusual facial features which may change over time; excessive drooling; small head and jaw; wide eyes; http://www.youtube.com/watch?v=TYQrzFABQHQ

HUMAN GENOME A ”map” of the genes on chromosomes *If you know where traits are, might be able to fix it

GENETIC TESTING Way to see if someone has the gene for a disease Before birth After birth

KARYOTYPE Picture of chromosomes Can help show problems with chromosomes

GENE THERAPY Replacing a defective gene with a correct gene to treat a genetic disease * New science technology

YOU ARE DONE WITH THE NOTES MAKE SURE YOUR NAME IS ON IT YOU WILL TURN THIS IN WITH YOUR PAPER TODAY – and get it back tomorrow *THIS STUFF WILL NOT BE ON THE QUIZ TOMORROW