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Genetic Alterations Patho Test#2

STUDY
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human disease classified in 3 categories
-genetics
-environmental
-genetic and environmental
Genotype
genetic constitution
Phenotype
expression of genetic make-up.
AO and AA are phenotypically type A.
Karyotype
lab. generated model of chromosomes
Penetrance
degree to which a genetic trait reveals itself.
ex. short fingers in fan with normal fingers.
Expression
way genetic trait reveals itself.
ex. deafness in one child in left ear, and the other in right ear.
Chromosome
carrier of genetic material.
autosomes
23 pairs of non-sex chromosomes
Gene
site on chromosome that carries a specific piece of genetic info
Pedigree
plotting of genetic trait through a family
Mutation
permanent change in DNA
DeNovo Mutation
Sudden appearance of a genetic trait in a non-carrier pedigree
Teratogen
substance that acts on embryo or fetus that leads to abnormalities.
Multifactorial disorders
combination of genes and environ. that lead to serious defects.
Aneuploid
any number greater than 46 chromosomes
Triploidy
3 sets of a normal haploid
Sex chromosomes
-only genetic material carried on Y gene is gender. no diseases associated with defective genes on this.
-when disease carried on X chromosome make us always more affected
-the more X chromosomes, the greater the damage.
Monsomy
the result when one sex chromosome is lost in a pair
-lethal
Autosomal Trisomy
3rd chromosome at one pair
-Downs syndrome
-may adversely affect development but infants may be born alive and survive
Structural chromosomal abnormalities
-deletions
-translocations (piece of each chromosome; btwn)
-inversions
Turners Syndrome
-sex chromosome abnormality
-only 1 chromosome. monosomy of one X chromosome.
-causes hypogonadism
Features of Turners Syndrome
-sex chromosome abnormality
-never develop secondary sex characteristics.
-sterile
-short stature
-Webbed neck
-broad widely spaced nipples
Klinefelters Syndrome
-sex chromosome abnormality
-extra X
-tall and small testes and penis
-never achieve sexual maturity
-spermatogenesis is absent
-infertile
-Eunichoid body types
-no body hair
-gynecomastia
-mental retarded
Downs Syndrome Trisomy 21
-autosomal chromosomal abnormality.
-many of congenital heart disease, risk for leukemia, develop alzheimers disease
-social develop> intellectual develop
-s/s: mental defect, almond shaped eyes, macroglossia, flat filtrim, everted nares, simian creases
Alleles
-all genes are located on autosomes occur in pairs.
-classified as dominant or recessive
-one complete set of genes comes from each parent
Homozygote
person with two identical members of a pair of alleles. AA
Heterozygote
person with two different members of a pair of alleles. AO
Autodominant disorder
transmitted by single gene and fully expressed in the heterozygote. 50% chance of being transmitted to offspring and if inherited they have disease.
Marfans disease
-autosomal dominant disorder
-multisystem disease caused by gene that encodes for intercellular protein called fibrillin. --Variable expression.
-s/s: tall with arachnodactyly, loose joints, cataract and lens dislocations, freq. luxations, cardiovascular disease including floppy valve syndrome and aortic aneurysms.
Achondroplasia (Dwarfism)
-autosomal dominant disorder
-defect of endochondral ossification
-defect in gene encoding for receptor for fibroblast growth factor
Huntingtons Chorea
-autosomal dominant
-gene #4 is defective
-presented in mid-life
-dementia with chorea
-accompanied by affective outbursts
-pedigree is very clear one
Autosomal recessives
-apparent only if both alleles are present
-must be homozygote to show signs of disorder
-both parents are usually asymptomatic carriers of abnormal gene; don't have it just carries it
Cystic fibrosis
-Autosomal recessives
-most common
-mutation of gene on chromosome #7 which encodes for the transport of chloride across the cell membrane
-defect affects pancreas, bronchial glands and GI system
-2/10 gentamicin
Gentamicin toxicity
complaint of tinnitus, oliguria, dark urine, BEAR
Characteristics of CF Pts
-fatty, foul smelling stool
-salty sweat
-freq UTIs
-Protuberant
-hypoxemia leading to clubbing and squatting
PKU
-Autosomal recessives; inborn errors of metabolism
-systemic disorder due to def. of phenylalanine hydroxylase causing accumulation of phenylketones in the body.
-progressive deterioration of mental function in early childhood
Tay Sachs Disease
-Autosomal recessives; inborn errors of metabolism
-mental deterioration and death due to accumulation go gangliocide in neuro cells
Albinoism
-Autosomal recessives; inborn errors of metabolism
-individual lacks ability to make Melanin due to absent enzymes
Sex linked disorders
-mutations of gene on X chromosome
-male more affected than female
-sons inherit disease from mother
-daughter affect defective gene from parents and are asymptomatic
Duchennes Muscular Dystrophy
-partial deletion of large gene that encodes for dystrophin
-males
-hypertrophic calf muscles
Type of Hemophilia
-Type A: classic. deficient in factor 8, passed to son by asymptomatic mom and males severely affected
-Type B: christmas disease, mild, deficient in factor 9
-Type C: rosenthals disease, transmitted as an autosomal recessive, not sex linked, def. in factor 11 and mild
Hemophilia
disrupt coagulation; can't cloot
Fragile X Syndrome
-form of mental deficiency due to a fragile sure on the x chromosome
-male: horse shaped head, square jaw, large testes, secure retardation
-female: horse shaped head, mental function varies, can mate
Multifactorial inheritance
-polygenic
-evolve at diff rates in diff ppl
-influenced b age, gender, race, social and environ
-reflect balanace btwn genetics and environ
polygenic
disease that have hereditary base and are mediated by more than one gene
Disorders of hostile environment
-amniotic bands
-FLK syndrome- due to abnormal pressure from amniotic fluid
Genomic mapping
-genome is the gene complement of the human
-id and assign of particular genes to particular chromosomes or parts
-2 types: genetic maps: measure distance btwn chromosomal landmarks
physical maps: measure physical distance btwn chromosomal elements like nucleotide base (more sophisticated)
Recombinant DNA technology
nucleic acids chopped up and genes recombined into hybrid molecules then put into an unicellular molecule which clones itself and rep common ancestor
Clonning
DNA molecule chopped up and reassembled. look for gene of interest that can be omitted or replicated
Gene therapy
-recombinant DNA tech. desired genetic material is injected into host.
-Two approaches: transferring genes to replace def genes or to inhibit potential harmful gene
-problem could hurt fetus or not enough to make diff.