1. Important Genetic Disorders Bio

2. Definitions ► Autosomes- any chromosome that is not a sex chromosome. Not the “X” or “Y” ► Sex-linked- genes located on the sex chromosome. Usually on the “X” ► Nondisjunction- A chromosome mishap in meiosis

4. Huntington’s Disease ► Symptoms: Gradual Brain tissue loss in middle age. ► Defect: Inhibitor of brain cell metabolism ► Autosomal/somatic dominate ► 1/10,000

5. Cystic Fibrosis ► Symptoms: Mucus clogs lungs, liver, pancreas ► Defect: Failure of chloride ion transport mechanism ► Autosomal recessive ► 1/2080 whites most common disorder

6. Sickle Cell Anemia ► Symptoms: impaired blood circulation, organ damage ► Defect: Abnormal hemoglobin molecules – RBC’s ► Autosomal Recessive ► 1/500 African Americans -If heterozygous will not get malaria

7. Tay-Sachs Disease ► Symptoms: deterioration of CNS in infancy. ► Defect: Defective form of enzyme hexosaminidase A (Hex A) ► Autosomal recessive ► 1/1600 Jews of European descent

8. Phenylketonuria (PKU) ► Symptoms: Failure of brain to develop in infancy; if untreated causes death. ► Defect: defective form of enzyme phenylalanine hydroxylase ► Autosomal recessive ► 1/18,000 urine test, treated by diet until puberty.

9. Hemophilia ► Symptoms: failure of blood to clot ► Defect: defective form of blood-clotting agent. ► X-linked recessive ► 1/7,000

10. Muscular Dystrophy ► Symptoms: wasting away of muscles; short life expectancy ► Defect: muscle fiber degenerate ► X-linked recessive ► 1/10,000 “Jerry’s Kids”

11. Down’s Syndrome ► Symptoms: Mental retardation with abnormal physical features. ► Defect: extra “X” chromosome ► Non-disjunction of the 21 st pair of chromosomes ► Somatic chromosome ► Also called Trisomy 21

12. Klinefelter’s ► Symptoms: only in males, sterile, do not develop 2 nd sex characteristics. Below normal intelligence ► Defect: extra “X” in 23 pair of chromosomes ► Meiosis error- genotype XXY

13. Turner’s ► Symptoms: only in females, appear normal at birth, become stockier & shorter than other females- large necks, sex organs & breasts do not develop- sterile ► Defect: missing “X” chromosome in 23 rd pair ► Non-disjunction of sex chromosome ► Genotype XO