Download Genetic Disorders

Genetic Disorders
Chapter 14
Disease
Type of
Inheritance
Cystic Fibrosis
Autosomal
Recessive
Tay-Sachs
Disease
Autosomal
Recessive
(incomplete
dominance at
molecular level)
Sickle Cell
Disease
Autosomal
Recessive
(demonstrates
pleiotropy)
(Codominant at
molecular level)
Phenylketonuria
(PKU)
Autosomal
Recessive
Achondroplasia
Autosomal
Dominant
Huntington’s
Disease
Autosomal
Dominant
Symptoms/ Facts
● Most common lethal genetic disease in US
● Recessive phenotype  chloride ion transport channels are
defective, which leads to abnormally high Cl- outside of the cell
● High level of Cl- leads to mucus production which builds up in
the pancreas, lungs, digestive tract  leads to bacterial infections
● when immune cells come to treat the infection, their remains add
to the mucus  bad cycle
● Brain cells have a defective enzyme that does not metabolize
lipids; therefore lipids build up on the brain
● The buildup causes the brain to not function properly and leads to
seizures, blindness, and degeneration of motor and metal
performance
● Death within several months
● Common among Ashkenazic Jews (ancestors from central
Europe)
● Most common inherited disease in African Americans
● Caused by substitution of one amino acids in the hemoglobin
protein of red blood cells
● When oxygen content low, sickle cell hemoglobin molecules
crystallize into rods  sickle shape
● Symptoms  wide range; low # of RBC’s, fatigue, sharp pains,
and infections
● Being a carrier (heterozygous) is beneficial because if makes you
resistant to malaria (which is common in tropical Africa)
● Screened for at birth
● Cannot properly break down AA phenylalanine, which can
accumulate to toxic levels and cause mental retardation
● Put on strict diet and usually develop normally
● Dwarfism
● Homozygous dominant = lethal
● Heterozygous = dwarf
● Homozygous recessive = normal height
● Deterioration of the nervous system
● Does not show until mid to late 30’s  at that point may have
already passed it on to offspring
● Leads to death