Common Genetic Disorders

Cystic FibrosisRecessiveFacts: mucus in lungs & digestive tract is very

thick ; caused by point mutationSymptoms: 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-PhenylketonuriaRecessiveFacts: Missing an enzyme that breaks down phenylalanine (found in milk)Phenylalanine accumulates in the CNSSymptoms: mental retardation, abnormal growth patternsIncidence: more common in Irish/ rare in African Americans & JapaneseTreatments: Test newborns, change diet

Sickle-Cell AnemiaRecessive & CodominantFacts: sickle-shaped blood cells

block/clot up blood vessels; point mutation

Symptoms: pain in joints, anemia, weakness

Incidence: 1 in 375 African AmericansTreatments: 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 SyndromeNondisjunctionfemale, only 1 X b/c of NondisjunctionSymptoms: sterile, lack of sexual

development(no ovaries), short stature

Incidence:Treatments: none

HemophiliaRecessive, sex-linked

Facts: blood does not have clotting factors

Symptoms: bleed excessively or to deathIncidence: mainly in males (in the Royal

Family)

Treatments: inject themselves with purified clotting factors to prevent or stop bleeding

Color-blindnessRecessive, x-linked disorderFacts: Cones in eyes(color receptors) are

absent or lack of pigmentSymptoms: cannot tell difference between

certain colorsIncidence: mainly in males- passed from

mother; red-green color blindness most common

Seeing only black/white is rareTreatments: 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.)