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.)