Human Genetic Disorders

Phenylketonuria (PKU)

• human metabolic disorder caused by enzyme deficiency

• Cannot break down phenylalanine → buildup disrupts brain development

• If child eats phenylalanine during growth, intellectual disability occurs, however, a phenylalanine-restricted diet until brain development is complete can ensure survival

Sickle Cell Anemia

• blood disorder common in individuals of African descent

• gene mutation → abnormal hemoglobin molecule in RBC → if low oxygen availability, RBC becomes crescent shaped (sickling) → cells clump together → clogs small blood vessels

• abnormal hemoglobin containing RBC carries less oxygen to the tissues → fatigue

• membranes of RBC are small → easy breakage

Tay-Sachs Disease

• caused by a mutation resulting a deficiency of lysosomal enzyme → lipid accumulation in brain & destroys brain → mental and motor deterioration → death

Duchenne’s Muscular Dystrophy

• muscles suffer a loss of protein and contractile fibers and are replaced by fat and connective tissue

• weakening of muscles

Huntington’s Disease

• degeneration of the CNS → abnormal movements and mental deterioration

• abnormal gene interferes w/ normal metabolism in nerve tissue

Cystic Fibrosis

• disease of the exocrine gland; thick mucus from the lining of the digestive tract, pancreas, and respiratory track blogs passageways

• blockage of respiratory passages causes chronic bronchitis and pneumonia

Thalassemia

• also called Cooley’s Anemia

• common among people of Mediterranean descent

• anemic symptoms + splenomegaly + congestive heart diseases

Hemophilia

• Sex-linked genetic disorder on the X chromosome

• cannot produce factor VIII; necessary for blood clotting

Trisomy 21

• Down syndrome

• Risk factors increase if the mother’s ≥ 35 y.o