Chapter 3 Genetics

Gene

Fundamental unit of DNA

Epigenetic changes

Alterations in gene due to the environement

Epigenetic changes example

lifestyle, stressors, behaviors

Pharmacogenomics

gene function in response to medications

Genetics

Study of inherited traits

Genomics

Study of all the genetic material (not only genes)

DNA nitrogen bases

A,T,G,C

Gene

arrangement of nucleotide bases

Exons:

part of genome that codes for proteins

Introns

parts of genome that dont encode for proteins

Genome

all the genes in an organism

Genetic Mutation

damage or change to gene that alters code

Germ cell mutation

gametes affected: may be passed to offspring

Somatic cell mutation

body cells

not passed to offspring

Gene locus

chromosomes number, arm , region

EX: 7q21

7th chromosomes short arm in the 21st region

Human Karyotype

23 pairs ( 21 pairs autosome, 1 sex)

Trisomy 21

Down syndromes, extra copy of 21st chromosome

Transcription

DNA to mRNA, (RNA polymerase uses DNA to form mRNA, mRNA leaves nucleus)

Translation

mRNA to proteins, Ribosomes read mRNA, tRNA one end binds to nucleotide other has amino acid it needs. amino acids linked by peptide bonds

Do all cells contain the same genese

Yes

Enhancors and silencors

factors on DNA that affect transcription rates

Allele

gene inherited from one parents

Genotype

Genetic code

Phenotype

physical expression of the genes (ex color)

Autosomal traits

1 copy of dominant allele or 2 copies of recessive for expression

XX vs XY

does not have corresponding allele on the Y chromosome

Genetic pentrance

the ratio of ppl with the phenotype compared to genotype (effect vs having coding)

Mitochondrial DNA

inherited from the mother and damaged by free radicals

CRISPR

Clustered regulatory interspaced short palindromic repeates

Slow acetylator phenotype

some people have less of an enzyme needed to metabolize certain meds

Proto-oncogene vs oncogene

healthy vs unhealthy (uncontrolled cell proliferation)

oncoproteins

from oncogenes, make uncontrolled proliferation, cancer risk

Aneuploidy

Having diff amount of chromosomes other tahn 46

Translocation

when part of chromosome breaks and joins another

Deletion

part of chromosome is broken off and lost

Prenatal screenings

for ppl 35+, abnormal findings, close blood relatives, miscarragias, etc

Maternal serum screening

proteins from placenta and fetus

Chorionic villus sampling

commonly to 35+, 10-12 weeks of preg, sample of placenta screened, NOT. if twins bleeding, retroverted, (99% diagnosis of chromosomal abnormalities)

Amniocentesis

amniotic fluid between 16-18 weeks of preg

Percutaneous umbilical cord blood sampling

examines umbilical cord, high risk last result

Gene therapy

normal gene used to replace abnormal one

Familial Hypercholesterolemia

Children risk at heart attacks, autosomal dominant 19p, lack of LDL receptors

Hypercholosterolemia forms

homozygous and heterozygous but homo more severe

Hypercholesterolemia risk and sign

artherosclerosis, xanthelasma fat deposits under the skin

Famialial Adenomatous polyposis

autosomal dominant , mutated APC gene

Adenomatous polyposis risk

increased colon cancer risk, rectal bleeding, diarrhea, pain

Adenomatous polyposis screening

rec colonoscopy every 1-2 years beginning age 10-12 year

Marfans Syndrome

Autosomal dominant can be from sporadic mutation and is a CT disorder

Marfan syndrome affects

fibrillin affecting microfibrils which are important in heart, lungs, dura mater,

Age span with untreated marfans

30-40

Marfans syndrome s/s

tall, kyphoscoliosis, ligament hypermobility, heart murmur, dysrhythmia

Neurofribromatosis

autosomal dominant, some from sporadic mutation, two forms from diff chromosomes

Neurofibromatosis s/s

usually in late teenage years, cafeaulait spot, optic nerve tumor, tumros in iris

How to diagnose neurofibromatosis

genetic testing, CT, MRI, neuro exams

Ehlers-Danlos Syndrome

abnormalities in collagen synthesis

Ehlers-Danlos Syndroms s/s

diminished strength and integrity of skin joints, easy bruising, mitral valve prolapse, arterial aneurysms

Cystic fibrosis

autosomal recessive, most common in caucasions, defect in CFTR gene

CF affects

lung function bc excess mucus and pancreatic secretion bc doesn’t absorb nutrients as well

Lysosomal Storage Disease

failure of lysosomes allows for buildup of harmful substances (Ex; Tay-Sachs ,accumulation in CNS death by 3)

Niemann Pick disease

lysosomal storage disease, deficiency in sphinogomyelinase , death by 3, lipids buildup in brain, spleen, liver and lymph nodes

Gaucher Disease

most common lysosomal storage disease, 150 gene mutations can results from this

Wilsons Disease

autosomal recessive, copper accumaltes in liver and other organs

Wilsons Disease sign

kayser fleisher rings in eyes

G6PD Deficiency

common enzyme disorder, lack of G6P disrupts RBC resulting in hemolysis

Klinefelter Syndrome- Chromosomal

lack of development of testes, gynecomastia, and skeletal and cardiovascular abnormalities, decreased cognitive development, testosterone replacement needed

Turner Syndrome- only affects females one X is missingF

may result in spont. abortion, short and infertile, lack of breast development, estrogen therapy

Fragile X Syndrome

Disorder of X chromosome, cognitive impairment Retardation, autistic like behaviors, large ears

Down Syndrome

flat face, epicanthic folds, small ears, 80% have IQ of 25-50

Prader-Willi Syndrome

usually from sporadic genetic mutation, hypthalamic dysfunction, overeat,hypotonia, low IQ, short , hypogonadism

Angelmans Syndrome

inherited from mother, rare, neurological symptoms , often smile and laugh

Huntingtons Disease

two forms but common one is the adult one 35-44, no cure, decline in thibnking, mood changes, involuntary movements from brain changes