Common Genetic Disorders
Cystic Fibrosis
Recessive
Facts: mucus in lungs & digestive tract is very
thick ; caused by point mutation
Symptoms: makes breathing & digestion
difficult
Incidence: most common in Caucasians(whites)
1 in 2000 white; 1 in 25 carry recessive allele.
Treatments: frequent lungs infections, daily
therapy is needed to loosen & remove mucus
PKU-Phenylketonuria
Recessive
Facts: Missing an enzyme that breaks
down phenylalanine (found in milk)
Phenylalanine accumulates in the CNS
Symptoms: mental retardation,
abnormal growth patterns
Incidence: more common in Irish/ rare
in African Americans & Japanese
Treatments: Test newborns, change
diet
Sickle-Cell Anemia
Recessive & Codominant
Facts: sickle-shaped blood cells block/clot
up blood vessels; point mutation
Symptoms: pain in joints, anemia, weakness
Incidence: 1 in 375 African Americans
Treatments: bone marrow transplants,
medicines
Down’s Syndrome (Trisomy 21)
Nondisjunction (during Meiosis)
Facts: most common reason for mental
retardation; chromosomes failed to
separate
Symptoms: mental retardation, slanted eyes
Incidence: 1 in 900; most cases not
inherited
Treatments: none
Turner’s Syndrome
Nondisjunction
female, only 1 X b/c of Nondisjunction
Symptoms: sterile, lack of sexual
development(no ovaries), short stature
Incidence:
Treatments: none
Hemophilia
Recessive, sex-linked
Facts: blood does not have clotting factors
Symptoms: bleed excessively or to death
Incidence: mainly in males (in the Royal
Family)
Treatments: inject themselves with purified
clotting factors to prevent or stop bleeding
Color-blindness
Recessive, x-linked disorder
Facts: Cones in eyes(color receptors) are absent
or lack of pigment
Symptoms: cannot tell difference between
certain colors
Incidence: mainly in males- passed from
mother; red-green color blindness most
common
Seeing only black/white is rare
Treatments: none
See the next slide if you are interested in extra
credit---
For extra credit on the binder check, continue
with a chart just like the one you just finished
including the following disorders:
• Tay-Sachs
• Progeria
• Albinism
• Huntington’s Disease
• Klinefelter Syndrome
(2 pts. For each one you do extra = 10 pts.)