Genetic Diseases & Disorders Biology

Genetics Diseases outline Dominant 1. Huntington’s Recessive 1. Cystic fibrosis 2. Sickle-cell anemia 3. Tay-Sachs 4. Phenylketonuria Sex-linked 1. Hemophilia 2. colorblindness Chromosomal 1. Turners 2. Klinefelters 3. XYY 4. Down syndrome Karyotype: Aneuploidy:

Huntington’s Disease: Dominant Lethal Age Breakdown of areas in brain cause uncontrolled jerky movements of head & limbs Mental deterioration Problem: have already passed it on before being diagnosed.

Cystic Fibrosis: Recessive Lethal (but treatable) White Americans Thick mucus in lungs & digestive tract making breathing difficult.

Sickle- Cell Anemia: Recessive Lethal Black Americans Sickle- shaped (half- moon) red blood cells Anemia ( low # of red blood cells, hemoglobin carries oxygen) Or clogging of blood vessels Heterozygous resistant to malaria, co dominant Spleen infected with Sickle Cells

Tay- Sachs Recessive Lethal Begin at age 1, most die by age 5 More common in Jewish people Blindness Loss of movement Mental retardation Lipids accumulate in brain Typical Pedigree for Tay-Sachs

Normalvs. Tay- sachs affected tissue

Phenylketonuria (PKU): Recessive Treatable Norweigan, Suisse Body cannot break down amino acid phenylalanine Damage to nervous system and mental retardation Now tested for shortly after birth, found in diet sodas

Hemophilia: sex-linked (carried on X chromosome), recessive Treatable, can be LETHAL Males more common because only one X chromosome Blood doesn’t clot making bruising dangerous

Hemophilia If a male has hemophilia, from which parent did he inherit the disorder? mother If a female has hemophilia, from which parent did she inherit the disorder? father, but mother must be carrier

Red-green color blindness recessive, sex-linked trait located on the X chromosome Not lethal More common in males because only one X chromosome individuals unable to see red and green colors due to damaged cones in eyes

How do things look to a colorblind person? Click below

Turners Syndrome X-linked Not Lethal Females XO Only one X chromosome, so they are female but they lack ovaries.

Klinefelters: X- linked Not Lethal Males XXY Males born with extra X chromosome taller than average Sterile Mental retardation

XYY: X- linked Not Lethal Males XYY Males with extra Y chromosome Usually taller than average, but otherwise normal

Down Syndrome: Trisomy 21 (has 3 instead of 2 copies of chromosome 21) Not lethal (shorter lifespan) Older mothers (over 40) Mental retardation Short stature

From looking at a karyotype (chart of chromosome pairs arranged from largest to smallest), You can determine if a child has Aneuploidy: abnormal # of chromosomes, caused by nondisjunction (homologous chromosomes fail to separate) Ex. Down syndrome, Turners, XYY, Klinefelters