Genetic Influence in Disease Flashcards
GENETIC DISORDERS
A disease caused by abnormalities in an individual’s genetic material
Can either be spontaneous or inherited
MITOCHONDRIAL DISORDERS
Disorder caused by the mutation or alteration of the minute amounts of DNA found in the mitochondria. Very uncommon
MULTIFACTORIAL GENETIC DISORDERS
Disorders caused by environmental triggers and variations/mutations of genes, plus sometimes inherited tendencies
Examples include cancers, common disease (HTN, DMII, CAD), and teratogenic disorders
TERATOGENIC DISORDERS
A teratogen is any influence (drugs, radiation, viruses) that can cause congenital defects
Abnormalities that are either detectable at birth and/or can be attributed to fetal development “glitches”
CHROMOSOMAL DISORDERS
Genetic disorders that result from alterations to the numbers or structure of a chromosome. This alters the local genes - the genes functionality is disrupted and won’t code proteins properly
ANEUPLOIDY
Alteration to the NUMBERS of chromosomes. A generic term for “more than usual numbers of chromosomes” would be polysomy.
DOWN’S SYNDROME
A disorder of abnormal numbers of chromosomes that are generally associated with pregnancies of women > 35 years old.
Occurs very early in cellular division, through a glitch in chromosomal distribution.
The fetus ends up with 47 chromosomes, the extra chromosome being on the 21st chromosome set. Another name for Down’s is Trisomy 21
Includes: mental retardation, low-set ears, epicanthic fold to the eyes, short limbs, and large tongue
PHILADELPHIA CHROMOSOME
This is an example of alterations to the STRUCTURE of chromosomes
Caused by alterations in chromosomal structure - such as deletion, duplication, or rearrangement of gene sites (translocation)
SINGLE-GENE DISORDERS
Disorders that are usually due to an inherited mutated gene.
Mutated genes produce poor protein products that can no longer carry out their normal functions
Include: autosomal recessive, autosomal dominant, and sex-linked
AUTOSOMAL RECESSIVE DISORDER
Occurs when a mutated recessive gene partners with an allele that is also recessive and mutated
Notated with two lowercase letters ( aa )
SICKLE CELL ANEMIA
Abnormal recessive alleles will code for abnormally-shaped hemoglobin (sickle-shaped) which will makes red blood cells sickle-shaped. ( ss )
More easily damaged red blood cells as they go through the blood stream, leading to abnormally low numbers of RBCs, leading to anemia
SICKLE CELL ANEMIA (S&S/Patho)
S&S: Shortness of breath, weakness, and fatigue due to decreased oxygen being carried to tissues in the body
Patho: anemia – less numbers of red blood cells to carry the hemoglobin which in turn carries the oxygen
Deformed hemoglobin can’t carry the usual numbers of oxygen molecules
S&S: Ischemic pain, especially in the points
Patho: deformed red blood cells clog up the capillaries that usually carry oxygen rich blood to tissues
Distal tissues are starved for oxygen
ss: sickle cell anemia
Ss: “having the trait”, very rarely exhibit S&S, but are carriers and can pass the trait (heterozygous)
SS: does not have disease and is not a carrier (homozygous)
AUTSOSOMAL DOMINANT DISORDERS
Occurs when a person inherits a mutated gene that is dominant. The disease characteristic is dominant, the normal characteristic is recessive ( Aa )
POLYCYSTIC KIDNEY DISEASE (PKD)
During fertilization, a kidney tissue gene is inherited that has a mutation and will code for abnormal kidneys. Regardless of what gene is paired with this gene, it will override that gene as it is the dominant of the two.
Kidney tissue commonly develops cysts, which reduces normal kidney functions and leads to kidney failure as the patient goes through life
POLYCYSTIC KIDNEY DISEASE (S&S/Patho)
S&S: hematuria (blood in urine), proteinuria (protein in urine), frequent kidney infections
Pain at costovertebral angles and abdomen
Kidney stones
PP / Pp: PKD
pp: normal kidneys
SEX-LINKED DISORDERS
Generally known as X-linked disorders.
Women are XX and each allele is partnered to the same locus on the other allele. So if one X allele is diseased it is protected by a normal dominant allele on the other X
Men are XY and therefore do not have comparable partner alleles between the X chromosome and Y chromosome. Therefore, almost all sex-linked disorders occur in male offspring
Can be X-linked dominant, X-linked recessive, and Y-linked
HEMOPHILIA
Caused by mutations on the X chromosome.
Gene for coagulation factors that facilitate normal clotting factors (Factor XIII and Factor IX) are mutated, resulting in an altered ability to clot properly.
Genotypes are different than normal alleles, since they are sex linked:
Xh XH, XH XH, or XH Y
RECOMBINANT DNA
A form of genetic engineering, which results in “new” DNA by combining two ore more different sources of DNA.
Applications include:
Human growth hormone for children lacking it
Exogenous insulin for diabetics
Factor VIII for hemophiliacs
tPA and tenecteplase - “clot-busters” for patients having myocardial infarctions.
