uses of genomic information in the diagnosis of disease
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Uses of Genomic Information in the
Diagnosis of Disease
Uses of Genomic Information in the
Diagnosis of Disease
What is Genomics?What is Genomics?
Genetics is the study of inheritance or the way traits are passed down from one generation to another Genes have the information to make proteins which direct cell activities and functions and influence traits such as hair and eye color
Approximately 30,000 genes in the human DNA Genomics is a newer term describing the study of all of a person’s genes and the interactions of those genes with each other and with the environment
Genetics is the study of inheritance or the way traits are passed down from one generation to another Genes have the information to make proteins which direct cell activities and functions and influence traits such as hair and eye color
Approximately 30,000 genes in the human DNA Genomics is a newer term describing the study of all of a person’s genes and the interactions of those genes with each other and with the environment
Importance of GenomicsImportance of Genomics
Genomics have a role in 9 of the 10 leading causes of death in the US http://www.cdc.gov/nchs/fastats/deaths.htm
All humans have 99.9% identical genetic makeup
The remaining 0.1% difference may provide useful information about diseases
The goal of genetics is to show why some people get sick from certain infections and environmental changes while others do not.
Genomics have a role in 9 of the 10 leading causes of death in the US http://www.cdc.gov/nchs/fastats/deaths.htm
All humans have 99.9% identical genetic makeup
The remaining 0.1% difference may provide useful information about diseases
The goal of genetics is to show why some people get sick from certain infections and environmental changes while others do not.
Human Genome Project (HGP) Human Genome Project (HGP) A 13 year project where all of the genes in the human DNA were discovered
Determined the sequences of approximately 3 billion chemical base pairs that make up the human DNA
Completed in 2003 by the U.S. Department of Energy and the National Institutes of Health with help from many other countries including Japan, Germany and France
A 13 year project where all of the genes in the human DNA were discovered
Determined the sequences of approximately 3 billion chemical base pairs that make up the human DNA
Completed in 2003 by the U.S. Department of Energy and the National Institutes of Health with help from many other countries including Japan, Germany and France
What are genetic disorders?
What are genetic disorders?
A disease caused in whole or in part by a variation or mutation of a gene
Researchers are discovering that nearly all diseases have a genetic component
A disease caused in whole or in part by a variation or mutation of a gene
Researchers are discovering that nearly all diseases have a genetic component
What are genetic disorders?
What are genetic disorders?
Some are caused by a mutation in the gene or group of genes in a person’s cells These may be random or from environmental exposure such as cigarette smoke
Others are hereditarythe mutated gene is passed down through the family
Most are multifactorial inheritance disorders-caused by a combination of small variations in genes, often connected with environmental factors
Some are caused by a mutation in the gene or group of genes in a person’s cells These may be random or from environmental exposure such as cigarette smoke
Others are hereditarythe mutated gene is passed down through the family
Most are multifactorial inheritance disorders-caused by a combination of small variations in genes, often connected with environmental factors
Three Categories of Genetic Disorders
Three Categories of Genetic Disorders
1) Single Gene Disorders Caused by a mutation in a single gene. The mutation may be present on one or both chromosomes
Such as Sickle cell disease, cystic fibrosis and Tay-Sachs
2) Chromosome Disorders-caused by an excess or deficiency of genes on the chromosomes or structural changes within chromosomes-Down syndrome
1) Single Gene Disorders Caused by a mutation in a single gene. The mutation may be present on one or both chromosomes
Such as Sickle cell disease, cystic fibrosis and Tay-Sachs
2) Chromosome Disorders-caused by an excess or deficiency of genes on the chromosomes or structural changes within chromosomes-Down syndrome
Three Categories of Genetic Disorders
Three Categories of Genetic Disorders
3) Multifactorial Inheritance Disorders-caused by a combination of small variations of genes-heart disease, most cancers, and behavioral disorders such as alcoholism, obesity, mental illness, and Alzheimer’s disease are examples
3) Multifactorial Inheritance Disorders-caused by a combination of small variations of genes-heart disease, most cancers, and behavioral disorders such as alcoholism, obesity, mental illness, and Alzheimer’s disease are examples
Genetic TestingGenetic Testing
Today more than 900 genetic tests are available.
There are also suseptability tests which can determine an estimated risk for developing the disease
List of common tests available: http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetest.shtml
Database for the entire human genome www.genome.gov
Today more than 900 genetic tests are available.
There are also suseptability tests which can determine an estimated risk for developing the disease
List of common tests available: http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetest.shtml
Database for the entire human genome www.genome.gov
Genetic Testing: How it Works
Genetic Testing: How it Works Scientists scan a patient’s DNA for
mutated sequences The DNA sample can come from any tissue including blood
For some tests, probes, short pieces of DNA, are designed with sequences complimentary to the mutated sequence. The probe will seek its compliment among the base pairs and will bind to it and flag the mutation
Other tests compare the bases in a patient’s gene to that of a normal gene
Scientists scan a patient’s DNA for mutated sequences
The DNA sample can come from any tissue including blood
For some tests, probes, short pieces of DNA, are designed with sequences complimentary to the mutated sequence. The probe will seek its compliment among the base pairs and will bind to it and flag the mutation
Other tests compare the bases in a patient’s gene to that of a normal gene
Genetic Tests: Types Available
Genetic Tests: Types Available
Carrier Screening-- Identifies unaffected individuals who carry one copy of the gene that needs two to express the disease
Preimplantation genetic diagnosisembryo from in vitro
fertilization is tested before implanted in the uterus
• Prenatal Diagnostic Testing Newborn screening
Carrier Screening-- Identifies unaffected individuals who carry one copy of the gene that needs two to express the disease
Preimplantation genetic diagnosisembryo from in vitro
fertilization is tested before implanted in the uterus
• Prenatal Diagnostic Testing Newborn screening
Prenatal diagnostic testing:
What tests show
Prenatal diagnostic testing:
What tests show Neural tube defects Birth defects of the brain or spinal cord
Chromosomal AbnormalitiesIndicated by abnormal amounts of substances in the mother’s blood such as alfa-feto protein and estriol
Most fetuses with these abnormalities die before birth
Neural tube defects Birth defects of the brain or spinal cord
Chromosomal AbnormalitiesIndicated by abnormal amounts of substances in the mother’s blood such as alfa-feto protein and estriol
Most fetuses with these abnormalities die before birth
Prenatal diagnostic testing:
Types of tests
Prenatal diagnostic testing:
Types of tests Ultrasonography
Performed before other tests to detect obvious structural defects in the fetus
Chorionic Villus Sampling A doctor removes a small sample of the chorionic villi, which are small projections that make up part of the placenta
Can be done between 10-12 weeks of pregnancy so the diagnosis is earlier
Ultrasonography
Performed before other tests to detect obvious structural defects in the fetus
Chorionic Villus Sampling A doctor removes a small sample of the chorionic villi, which are small projections that make up part of the placenta
Can be done between 10-12 weeks of pregnancy so the diagnosis is earlier
Prenatal diagnostic testing:
Types of tests
Prenatal diagnostic testing:
Types of tests Amniocentesis
One of the most common prenatal tests
A sample of amniotic fluid is removed and tested for alpha-fetoprotein level
Amniocentesis One of the most common prenatal tests
A sample of amniotic fluid is removed and tested for alpha-fetoprotein level
AmniocentesisAmniocentesis
EpidemiologyEpidemiology
Human Genome Epidemiology http://www.cdc.gov/genomics/hugenet/default.htm
The use of the human genome to study vast groups of people
HGDPHuman Genome Diversity ProjectUses genomics to study different diseases affected by a person’s genes among ethnic groups
Human Genome Epidemiology http://www.cdc.gov/genomics/hugenet/default.htm
The use of the human genome to study vast groups of people
HGDPHuman Genome Diversity ProjectUses genomics to study different diseases affected by a person’s genes among ethnic groups
Benefits of Genetic Testing
Benefits of Genetic Testing
Some tests can clarify a diagnosis for a more concise treatment
Other tests can prevent families from having children with devastating diseases
Some tests can clarify a diagnosis for a more concise treatment
Other tests can prevent families from having children with devastating diseases
Disadvantages of Genetic TestingDisadvantages of Genetic Testing
Commercialized gene tests for adult onset disorders and some cancers For presymptomatic people at high risk because of family medical history
They only give a probability for developing the disorder
People who carry the mutation may never develop the disorder
Possibility for errors due to contamination or misidentification
Cost can range from hundreds to thousands of dollars
Commercialized gene tests for adult onset disorders and some cancers For presymptomatic people at high risk because of family medical history
They only give a probability for developing the disorder
People who carry the mutation may never develop the disorder
Possibility for errors due to contamination or misidentification
Cost can range from hundreds to thousands of dollars
Gene TherapyGene Therapy
Gene therapy is a technique for correcting faulty genes which cause diseases
Genes are specific sequences of bases that encode instructions on how to make proteins which perform most cellular functions and make up the majority of the cellular structure
When defective genes encode proteins unable to perform properly, genetic disorders can occur
Gene therapy is a technique for correcting faulty genes which cause diseases
Genes are specific sequences of bases that encode instructions on how to make proteins which perform most cellular functions and make up the majority of the cellular structure
When defective genes encode proteins unable to perform properly, genetic disorders can occur
Methods of Gene Therapy
Methods of Gene Therapy
A normal gene may be inserted into a non-specific location within the genome to replace a faulty gene (most common method)
The abnormal gene can be swapped for a normal gene through Homologous Recombination.
A normal gene may be inserted into a non-specific location within the genome to replace a faulty gene (most common method)
The abnormal gene can be swapped for a normal gene through Homologous Recombination.
Homologous RecombinationHomologous
Recombination The process where two homologous chromosomes exchange a
distal portion of their DNA during prophase 1 of meiosis. The two homologous chromosomes break and reconnect to the different end piece. If they break at the same place in the base pair sequence, the result is an exchange of genes called genetic recombination. It could be as often as several times per meiosis.
The process where two homologous chromosomes exchange a distal portion of their DNA during prophase 1 of meiosis. The two homologous chromosomes break and reconnect to the different end piece. If they break at the same place in the base pair sequence, the result is an exchange of genes called genetic recombination. It could be as often as several times per meiosis.
Methods of Gene Therapy
Methods of Gene Therapy
The abnormal gene can be repaired through Selective Reverse Mutation, returning the gene to its normal function
The regulation of a gene, the degree to which it is turned on or off can be altered
The abnormal gene can be repaired through Selective Reverse Mutation, returning the gene to its normal function
The regulation of a gene, the degree to which it is turned on or off can be altered