 Recall:  Autosome - any chromosome other than the X & Y (humans have 22 pairs of autosome + 1 pair of sex chromosomes)

 Most affected children have unaffected parents  Heterozygotes (carriers) are unaffected

Tay - Sachs Disease  More common among Jewish populations  Young children begin showing signs of slowed development  Severe impairment and death Build up of lipids in the body – lysosomes do not function properly

Cystic Fibrosis  More common in Caucasians  Mucus in respiratory tract, difficulty breathing  Extreme salty sweat  Mucus may cause secondary infections

Phenylketonuria (PKU)  Lack enzyme for normal metabolism  Phenylalanine builds up and causes brain damage  Newborns are routinely tested  Changes in diet lead to normal life

Sickle Cell Disease  More common in Africans (African-Americans)  Causes blood to be sickle shaped  Affects oxygen flow to organs, causing weakness, pain, anemia, etc  Heterozygotes are resistant to malaria

 Affected children usually have an affected parent  Heterozygotes are effected  Two heterozygotes (Hh x Hh) can produce a normal (hh) child

Huntington Disease  Neurological disorder, progressive degeneration of the brain  Symptoms appear later in life (40s, 50s)

Achondroplasia  Common form of Dwarfism  Short arms and legs, normal torso  Homozygotes (AA) do not survive

 Achondroplasia

Hypercholesterolemia  Incomplete dominance  Caused by a recessive allele, however in the heterozygous form (Hh), individuals have 2x the normal blood cholesterol levels