Patho Genes And Genetic Diseases

Front 1

Why should we seen genes and genetic diseases

Back 1

- influences everything
- differentiate things that are not genetic
- if its linked to gender, environment
- what happens if 2 carriers have babies

Front 2

why do we study genetics

Back 2

educate pt about causes
(alcohol = FSA)

Front 3

what competencies should nurses possess

Back 3

that effects don't have to be seen at birth to have a disease it can show up later in the life

Front 4

What do we look for on a medical genetic family pedigree

Back 4

- wellness & illness
- Birth – live, stillborn, miscarriage
- Birth defects
- Inherited and familial disorders - if all males/females, skin, generation
- Cancer, heart disease, diabetes - familial
- Age at diagnosis - if you are affected will be around time (age) parents began to have it
- Must be confirmed by a medical professional - serious of test have to be done

Front 5

Genetic Evaluation and Counseling

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- Implication for reproduction. - what are the chances the baby will have the disease, if there should be termination, age of mom, still birth or SIDS, infertility issues, marriage to blood relatives
- Implication for developmental history. - mental retardation, failure to thrive, height, abnormalities in growth or delay in 2nd sex characteristic or organ
- Implication for family history. - present of known condition, multi dis-organ disorder, familial cancer, early onset of certain disorder

Front 6

Human Genome Project

Back 6

- DNA discovered in 1953 by Watson and Crick
- Became the foundation for the Project
- Started in 1990
- Completed in 2003
- 2 years in advance of projected completion date of 2005!
- The human genome's gene-dense "urban centers" are predominantly composed of the DNA building blocks G and C.
- In contrast, the gene-poor "deserts" are rich in the DNA building blocks A and T. GC- and AT-rich regions usually can be seen through a microscope as light and dark bands on chromosomes.
- Genes appear to be concentrated in random areas along the genome, with vast expanses of noncoding DNA between.
 - Stretches of up to 30,000 C and G bases repeating over and over often occur adjacent to gene-rich areas, forming a barrier between the genes and the "junk DNA." These CpG islands are believed to help regulate gene activity.
- Chromosome 1 has the most genes (2968), and the Y chromosome has the fewest (231).
- mapped everything
- location & structure of genes
- want to arctic or limit genetic disease, who is likely to inherate
- it improve tx, how ATCG is arrange
- Variations and Mutations
* Scientists have identified about 3 million locations where single-base DNA differences (SNPs) occur in humans. This information promises to revolutionize the processes of finding chromosomal locations for disease-associated sequences and tracing human history.
* The ratio of germline (sperm or egg cell) mutations is 2:1 in males vs. females. Researchers point to several reasons for the higher mutation rate in the male germline, including the greater number of cell divisions required for sperm formation than for eggs.
- Prior to 1990 . . .
* About 5,000 identified genetic conditions/genes
* Over 10,000 new genetic conditions/genes were identified as a result of the HGP.
* Currently, either a new function or a new gene is begin discovered at the rate of > 2/day.

Front 7

Bioethical, Legal, and Social Issues

Back 7

- Ownership of genetic information? - patient. health care provider owns the chart but the work in the direction of the patient
- Access to genetic information? - grey area (insurance) as much as they need to know to get bills paid
- Genes and behavior control? - to make the person we want in the world
- Use in reproductive issues? - determine how can baby get it

Front 8

Issues for Healthcare Professionals

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- *Privacy/Confidentiality*
- Discrimination - cant with hiring
- Research – prevention and treatment
- Pharmacogenomics - how ones genetic code responds to medication. Can be serious
- Gene therapy - normal genes are inserted into the code to correct the disease
- Genetic engineering - using best genes to create the best outcome (super human)

Front 9

The Genetic Code

Back 9

DNA -> RNA
RNA -> protein
Protein -> polypeptides
Polypeptide -> amino acids -> bases
Bases as triplet (AKA codons)
Sequence of triplet or codon represent a GENE!

Front 10

DNA → RNA → protein

Back 10

The process is:
1. DNA is reproduced (where HIV happens)
2. DNA is transcribed into messenger RNA - mess up = genetic affects/ diseases
3. Messenger RNA is translated into protein

Front 11

Cell Nucleus -> Chromosomes -> Genes -> DNA
DNA has 3 components:

Back 11

A pentose sugar molecule
A phosphate molecule
4 nitrogenous bases
cytosine (C)
thymine (T)
adenine (A)
guanine (G)
~ match up correctly to have = 3
~ if dont then have problems / disorders

Front 12

Genetic Code …

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- The combination of these bases (A,C,T, G) are arranged in codons (triplets of bases)
- Each codon specifies a single amino acid in a corresponding protein.
- A specific sequence of triplets represents a gene.

Front 13

DNA Replication

Back 13

- if only a couple dont match up can override
- big critical problem if omitted or deleted (not there at all)

Front 14

Mutation

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- Permanent change
- A change in the structure of DNA (permanent) - myotic cell
- Inherited – germline mutation - environment (smoking, radiation)
- Acquired – somatic mutation

Front 15

Types of Mutations

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- Silent
- Missense
- Nonsense
- Frameshift

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Silent

Back 16

no consquence (disease) make it normal

Front 17

Missense

Back 17

flip part some definite changes

Front 18

nonsense

Back 18

- whatever change that happens makes stop functions
- affects cause protein wasn't finish there but don't happen

Front 19

fameshift

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put more in take it out (delete) more serious concern change DNA molecule

Front 20

Chromosome Terminology

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- Gamete
* meiosis 46 chrom
* haploid # - sex cells
- Somatic
* mitosis
* diploid # - automate
* autosomes
(22 homologous pairs)
* sex chromosomes
-xx (female homologous)
-xy (male, nonhomologous)
* karyotype – an ordered display of chromosomes
* centromere and bands are key components. - need to be intact in not get disease/disorder bands need to be where they are suppose to be

Front 21

Abnormalities of Chromosomes

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Euploid cell - normal
Polyploidy - more then normal # of chrom
Triploidy (69) - extra set of chromo
Tetraploidy (92) - 4 times the number of chromo
Aneuploidy - abnormalities of chorm. Sex chromosome aneuploidy - turners (hallmark)
Monosomy,(chrom without match) trisomy (get the extra match)
Nondisjunction -stay together

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Autosomal aneuploidyDown Syndrome: Trisomy 21

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# - the chromo gone wrong
s/s - risk mom over 35
- upward set of eye
- small ears
- skin fold by eye
- tungue in large
- extra space between big toe & second
- simian crease -> deep across inter palm straight

Front 23

Trisomy 13

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- patau sydrome
- severe intellectual
- heart brain differ
- eye formation
- pterodactyl
- polypeptide - extra fingers & toes
- dies 1st few day/weeks
- 5% live past 1st year

Front 24

Sex Chromosome Aneuploidy

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- Turner Syndrome (45X, O)
- no Y's
- affects femals
- arms turn outward
- broad chest widely spread nipples
- small finger nails
- may no menstruate
- lower jaw

Front 25

Klinefelter’s Syndrome(47, XXY)

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- extra X in males
- polysomy X (more chromosome)
- genocamastea (female breast)
- small genitals
- few chest hair
- female type pubescent hair pattern
- happens about the time the boy is in middle school

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Chromosomal Abnormalities: Structure

structure is wrong

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- Deletion - deleting something
- Duplication - adding the same thing again (tries to match up with wrong stuff causes missing big defects)
- Inversion - the action of inverting something or the state of being inverted
- Insertion - placing something in a spot
- Translocation - is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes.
- Fragile site - has a gap in the chromosome
- Do not confuse with mutation!

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Translocation

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- moves around on chromosome itself so it wont match up

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fragile site

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- sites on chromosome that have very small gaps
- fragile X syndrome - males are affected

Front 29

Elements of Formal Genetics (Key Terms)

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- Allelle - gene at certain location with certain traits
- Homozygous (AA or aa) - same
- Heterozygous (Aa) - not the same
- Genotype = genetic composition - genes say what your going to have
- Phenotype = physical composition - physical how much
- Dominant = expressed as AA or Aa
- Recessive = expressed as aa
- Codominance
- Carrier
- Recurrence risks - chances of having
- Punnett Square - determine the chances of getting it

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Mendelian Patterns of Inheritance

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- Autosomal dominant
- Autosomal recessive
- X-linked dominant
- X-linked recessive
- Most hereditary disorders caused by autosomal dominant defects.

Front 31

Autosomal Dominant Inheritance

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- affects both not X link
- affects individual have affected patent
- 50% affected
- 50% normal
- same chance with each birth doesn't matter what other children
- ***NO CARRIERS***
- more pans long arms
- nerofibro physios
- hunnington

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Autosomal Recessive Inheritance

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- Usually early age onset
- CARRIERS!!
- Consanguinity - semi close relative. mating of family. closer relationship increased affect
- Penetrance - how prometive the gene is
- Expressivity - how much & how sever disorder is
- 1n 4 25% affect
- 50% carrier
- 25% normal

Front 33

Cystic Fibrosis

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- Autosomal recessive
- Multiple body systems affected
- Mild – moderate – severe symptoms
- Lungs and pancreas affected

Front 34

X-Linked Inheritance (Sex-Linked)

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- X-Linked Dominant
* very rare
* Fragile X
- no carriers present or doesnt
- vit D deficent ricket
- a affected child start chances over
- affected father = 100% daughters affected
- X-Linked Recessive
* more common
* almost always male
- when dad affected all daughter
- 25% daughter carrier 25% son affected 50% normal

Front 35

X Inactivation

Back 35

- One X is inactive (permanently) in the somatic cells
- AKA – **the Lyon Process**
- Dosage compensation
- Occurs in early embryonic development.
- doesnt affect female
- Cancels out errors
- so disease not powered
- so any X linked disorder

Front 36

Disorders of the Y Chromosome

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- male to male
- responsible for some stillbirths, spontaneous abortion
- usually no compatible with life

Front 37

Multifactorial Inheritance

Back 37

- Environmental factors - radiation, pollution
- Lifestyle choices and behaviors - smoking, FAS
- Familial genetics
- Common Disorders: cleft lip/palate, anencephaly, congenital heart defects, spina bifida, diabetes….
“- runs in the family”
- Genetic predisposition

Front 38

Congenital defects may not necessarily be related to genetics!

Back 38

- Period of vulnerability - 1st trimester
- Teratogenic agents
* Radiation
* Chemicals, drugs
- fetal ETOH syndrome, cocaine babies,
lack of folic acid
* TORCH infections
~Toxozplasmosis, O (syphilis, HIV, Versailles zoster) Rubella Cytomegally Hep septict 2 virues