Down Syndrome

• Have 3 copies of chromosome # 21 (trisomy)

• Nondisjunction genetic disorder

• Symptoms include cognitive delays, eyes that slant upward and heart defects

• Affects over 350,000 people in the U.S.

• No cure or treatment

Turner Syndrome• Have only one X

chromosome (monosomy)• Nondisjunction genetic

disorder• Symptoms include short

stauture, lack of ovariam development, webbed neck, arms that turn out, & low hairline in the back of the head.

• Affects 60,000 girls and women in the U.S.

• No cure or treatment

Klinefelter Syndrome• Have a Y & 2 X

chromosome (trisomy)• Nondisjunction genetic

disorder• Symptoms include males

that do not develop secondary sex characteristics such as facial hair & underarm hair.

• Affects 1 in 500 to 1 in 1000 male births in the U.S.

• No cure or treatment

Huntington’s Disease• Genetic mutation of a

normal gene in brain cells• Dominant genetic disorder• Symptoms include

uncontrolled movements, loss of intellectual faculties, & emotional disturbance

• Affects 1 in 10,000 in the U.S.

• Medications can be prescribed to help control emotional & movement

Normal Brain

Huntington’s Disease

Achondroplasia

• Faulty gene that is involved in bone growth

• Dominant genetic disorder

• Symptoms include short stature (problems with growth & development of the skeleton)

• Affects 1 in 20,000 births in the U.S.

• No cure or treatment

Albinism• Have little or no pigment

(melanin) in their eyes, skin, or hair

• Recessive genetic disorder• Symptoms include red

eyes, vision problems, & very light skin & hair.

• Affects 1 in 17,000 births in the U.S.

• Treatment: – Eye condition - surgery,

glasses, contact lenses– Skin - use UV skin protection

Tay Sachs Disease• Fatal genetic lipid storage

disorder where fatty substances build up in nerve cells in the brain

• Recessive genetic disorder• Symptoms include

deterioration of mental & physical abilities (blind, deaf, unable to swallow, muscle atrophy)

• Very rare - 1 in 27 people are carriers (Ashkenazi Jews) & 1 in 250 people are carriers (general population).

• No cure or treatment

Cystic Fibrosis• Approx. 30,000 people in US have

CF• Excessive mucus production• Defective CF gene produces

abnormally thick and sticky mucus• Digestive & respiratory failure• Recessive genetic disorder• Coughing or increased mucus in the

sinuses or lungs• Fatigue & Weight loss• Nausea and loss of appetite• No cure• Daily cleaning of mucus from lungs• Take mucus thinning drugs

Hemophilia• Mutation of genes for the

blood clotting factors on the X chromosome

• Sex-linked trait• Symptoms include bleeding

continuously until they are treated - blood does not clot.

• Affects about 18,000 people in U.S. (affects more men than women because women are more likely to be carriers)

• No cure or treatment

Color Blindness• Mutation of genes on the

X chromosome• Sex-linked trait• Symptoms include not

being able to identify any color or difficulty in telling different shades of color apart.

• Affects 8% of men & 1% of women (women are more likely to be carriers)

• No cure or treatment

Red-green color blindness – recessive and linked to the X chromosome

XC = Colorblind alleleXN = Normal allele

XNXN = Normal sightXNXC = Carrier for colorblindnessXCXC = ColorblindXCY = Colorblind