Genetic Disorder Quiz

cri du chat

results from a deletion in chromosome #5; severe mental retardation and a catlike cry

achondroplastic dwarfism

autosomal and dominant; one form of dwarfism; affects one in 10,000 people

huntington's disease

autosomal and dominant; this fatal disease begins to be expressed in middle age; a degenerative disease of the nervous system; loss of motor control progressing to total physical and mental incapability; results in certain and early death; individuals with this condition have a 50% chance of passing it onto their offspring

albinism

autosomal and recessive; a lack of pigmentation (melanin) resulting in very pale skin, hair, eyes, and increased susceptibility to skin cancers and vision problems

cystic fibrosis

autosomal and recessive; the most common lethal genetic disorder in US; 1/25 (4%) of Caucasians is a carrier; caused by a mutation on chromosome 7; the normal allele for this gene is involved in cellular chloride ion transport; the mutation results in a high concentration of extracellular chloride; characterized by a buildup of a secretion of thick mucus which accumulates in the lungs and digestive tract; if untreated, children with CF die at a young age

sickle cell anemia

autosomal and recessive; this person has abnormal hemoglobin; the hemoglobin is less efficient at carrying oxygen; it can also cause red blood cells to deform to a sickle shape; this causes red blood cells to be unable to effectively transport oxygen through the body; causes pain, muscle weakness, and fatigue; most common among African Americans; 1/10 African Americans is a carrier of this disease

PKU

autosomal and recessive; this person is unable to breakdown the amino acid phenylalanine; buildup of this amino acid causes mental retardation; if it is discovered early, this can be treated with a diet low in phenylalanine

tay-sachs disease

autosomal and recessive; this person lack the enzyme to break down certain lipids that accumulate in the brain; these accumulate in the brain cells and cause a progressive nervous system dysfunction leading to death; usually fatal by age 4; onset is early in life; more common (1/3,600 births) in Eastern European (Ashkenazic) Jews; results in seizures, blindness, and early death

turner's syndrome

nondisjunction of the sex chromosomes; a female with only one X chromosome; results from the union of a gamete that is missing the sex chromosome with a normal sperm or egg; short stature and sterile

klinefelter syndrome

nondisjunction of the sex chromosomes; a male with an extra X chromosome (XXY); results from the union of an XX gamete and a normal Y gamete; usually sterile; 47 chromosomes; small testes and may have some feminine characteristics such as breast enlargement

all nondisjunction disorders

Down syndrome, Klinefelter syndrome, turner's syndrome

all dominant disorders

achondroplastic dwarfism, Huntington's disease

all autosomal disorders

achondroplastic dwarfism, albinism, cystic fibrosis, Huntington's disease, PKU, sickle cell anemia, tay-sachs disease

down syndrome

affects 1/700 children born in US; nondisjunction of chromosome #21; three copies of chromosome 21 causes mental retardation and some physical abnormalities-- characteristic facial features, short stature, heart defects, and increased likeliness of developing leukemia and Alzheimer's disease; most are sterile

all recessive disorders

albinism, color blindness, cystic fibrosis, Duchenne muscular dystrophy, hemophilia, PKU, sickle cell anemia, tay-sachs disesase

all sex-linked disorders

color blindness, Duchenne muscular dystrophy, hemophilia,

Duchenne muscular dystrophy

sex-linked and recessive; affects 1/3500 males born in US; missing an essential muscle protein called "dystrophin"; resulting in deteriorating muscles and a loss of coordination; victims rarely live past their early 20s

hemophilia

sex-linked and recessive; missing one or more proteins necessary for normal blood clotting; when victims are cut, a firm clot is slow to form; bleeding in the muscles are joints are common and painful; 1/10,000 males are born with a form of this disorder

color blindness (red and green)

sex-linked and recessive; unable to distinguish red from green; approx. 8% of men have some form of this disorder