Many human disorders have a genetic component, but the onset of a disorder may vary depending on life conditions. Some disorders can be detected at birth, while others do not manifest themselves until an individual has reached a certain age range. Some disorders can be treated and managed, while others lead to debilitating symptoms and premature death. Research geneticists spend a great deal of time and money to better understand the genetic components of such disorders. Their ultimate goal is to detect, prevent, or fix the genetic component of these disorders.
Cystic Fibrosis
Cystic fibrosis (CF) is the most common fatal genetic disease in Canada. The life expectancy for individuals with CF is less than 40 years, though this is increasing every year—some individuals with CF have lived into their seventies. The disease causes the body to produce thick, sticky mucus that clogs the lungs, leads to infections, and blocks the release of enzymes from the pancreas. The pancreas produces digestive enzymes that help break down protein, fats, and carbohydrates during digestion, so children and adults who have CF must take a large number of replacement enzymes daily in pill form. In addition, individuals with cystic fibrosis must undergo physical therapy or other treatments every day to help loosen accumulated mucus in the lungs (Figure 1). [GOT TO NELSON SCIENCE]
Figure 1 A child undergoing physical therapy for cystic fibrosis. The child's chest or back is tapped repeatedly to loosen the mucus in the lungs. This makes it easier for the child to rid his body of the mucus.
Cystic fibrosis is the result of a mutation, or a change in the genetic code. The first such defective gene was isolated and identified in 1989 by research geneticist Dr. Lap-chee Tsui and his team at the Hospital for Sick Children in Toronto. The mutated copy of the gene is recessive, so a child must inherit both copies of the defective allele from his or her parents in order to express CF. In the past, parents realized that they were carriers only when their child was born with CF.
mutation a change in the genetic code of an allele; the change may have a positive effect, a negative effect, or no effect
Today, carrier testing is used to identify individuals who carry disorder-causing recessive genes that may be inherited by their children. In fact, the Canadian College of Medical Geneticists recommends that carrier testing for cystic fibrosis be available to anyone who has a family history of CF. Genetic counsellors work with couples that have an increased risk of conceiving a child with CF.
carrier testing: a genetic test that determines whether an individual is heterozygous for a given gene that results in a genetic disorder
Testing for the presence of the mutated gene in the genome is known as genetic screening. Currently, we are aware of approximately 200 mutations that lead to cystic fibrosis. The severity of symptoms depends on which DNA mutation an individual has. The genetic test is based on a blood sample that is sent to a molecular diagnostic laboratory. In Canada the test is able to detect approximately 85 % of CF mutations. Table 1 shows the probability of conceiving a child with CF according to different test result scenarios.
genetic screening: tests used to identify the presence of a defective allele that leads to a genetic disorder
CAREER LINK
Pulmonologist
A pulmonologist is a physician who specializes in respiratory diseases. To learn more about a career in pulmonology, GO TO NELSON SCIENCE
Table 1 Risk of Having a Child with Cystic Fibrosis before and after Carrier Testing in Canada
Test status of parents: No test performed Risk of having a child with CF: 1 in 2500
Test status of parents: Both partners tested: results show one positive, one negative Risk of having a child with CF: 1 in 600
Test status of parents: Both partners tested: results show both positive Risk of having a child with CF: 1 in 4
Source: Canadian Cystic Fibrosis Foundation, Carrier Testing for Cystic Fibrosis
From Mendel's Punnett square for a recessive autosomal trait, we know that the probability of two heterozygous parents (Ff and Ff) conceiving a child with CF (ff) is 25 %, a child who is a carrier (Ff) is 50 %, and a child who does not carry the mutation (FF) is 25 % (Figure 2). Therefore, if both parents have tested positive for the mutation, the probability of giving birth to a child with CF is 1/4, as indicated in Table 1.
Figure 2 The probability of these two parents conceiving a child who does not express cystic fibrosis is 75 %.
Image: A grid square. Over top of the grid square is Ff. On top of the top left square is F, and on top of the top right square is f. On the left side of the grid square is Ff. On the side of the top left square is F, and on the side of the bottom left square is f. The top left square is labeled FF, the top right square is labeled Ff, the bottom left square is labeled Ff, anf the bottom right square is labeled ff.
Print Page 205
Key
K/U: Knowledge and Understanding T/I: Thinking and Investigation C: Communication A: Application
Cystic fibrosis is a genetic condition that can be managed by a variety of therapies and lifestyles. In the past people with CF barely lived past childhood. Today, with treatment and healthy lifestyle choices, many people with CF live well into adulthood. They can go to school, pursue careers, play sports, and have families. Some individuals with CF even live to be senior citizens. With advances in genetics, it is quite reasonable to think that a child born with CF today may live to see a cure for the disorder.
1. Use the Internet and other resources to find stories about people who have cystic fibrosis.
2. Make a list of strategies that individuals with CF use to manage their condition. Research and record the ways each person's strategy helps him or her as stated by that individual.
A. What similarities do the strategies share? A
B. Think about how each person's strategies would fit into your daily life, if you had CE Describe in paragraph form how your daily schedule would change. Do you think some CF strategies could fit easily into your own lifestyle? What changes would you have to make? What would stay the same? C A
Breast Cancer
Not all genetic disorders appear right from the onset of life. As you learned in Section 5.4, Huntington's disease does not usually show up until an individual is at least middle-aged. At this point, the potentially harmful allele may have been passed on to offspring. Cancer genes also fall into this category. Cancer is uncontrolled cell division.
BRCA1 and BRCA2 are human genes that belong to a class of genes known as tumour suppressors. Tumour suppressors produce chemicals that inhibit the growth of tumours in the body. If a woman carries a defective copy of either of these genes, she has an increased chance of developing breast or ovarian cancer at an early age.
Not all breast cancers are caused by a mutation in the BRCA1 or BRCA2 gene. A woman has a 12 % chance of developing breast cancer if she does not carry a copy of one of the defective genes, but a chance of 60 % if she is a carrier of even a single copy of either the defective BRCA1 or BRCA2 genes. The environment plays a significant role in determining whether cancer genes are turned on or off. For example, a woman who is exposed to estrogen-mimicking chemicals found in some lawn pesticides and certain types of plastics has a greater chance of developing breast cancer. [GO TO NELSON SCIENCE]
A woman who has a family history of breast cancer may choose to undergo genetic screening for the mutated BRCA1 or BRCA2 gene. If she does have a mutation, she may decide to have a mastectomy, a procedure that involves the removal of part or all of the breast tissue. Alternatively, she may choose to increase surveillance of her breast and ovarian health.
WEB LINK
For more information on estrogen-leaching plastics, GO TO NELSON SCIENCE
Phenylketonuria
Breast cancer and cystic fibrosis are potentially fatal conditions caused by a mutation in a gene. In contrast, individuals with phenylketonuria (PKU) are able to live normal lives with modifications to their lifestyle.
Phenylketonuria is a genetic disorder in which the affected individual is unable to utilize the amino acid phenylalanine, which the body needs in order to make proteins and essential brain chemicals. In Canada, about 1 in 20 000 people have PKU. Individuals with PKU do not possess the enzyme that breaks down phenylalanine
phenylketonuria (PKU) an autosomal, recessive, inherited genetic disorder that results in the accumulation of phenylalanine in the tissues and blood
Print Page 206
(found in most foods), and it accumulates in the blood and tissue. The brain function of a child with PKU does not develop normally.
Phenylketonuria is a recessive trait. Both parents must be carriers of the defective allele in order to pass it down to the child. Unlike for cystic fibrosis, researchers have not isolated the phenylketonuria gene. Hence prospective parents cannot be counselled or tested for the probability of producing a PKU child. Instead, every newborn is screened for the presence of PKU.
When a baby is about three days old, a few drops of its blood are tested for elevated amounts of phenylalanine and other compounds that are associated with genetic disorders. If the test is positive, more tests are performed to confirm or rule out PKU. If the infant does suffer from PKU, he or she must follow a diet that severely limits intake of high-protein foods such as meat, fish, eggs, and milk. If the diet is followed, the child will be able to lead a normal life. If PKU is left untreated, the child will suffer arrested mental development, decreased body growth, and poor development of tooth enamel.
Other Disorders
Table 2 summarizes some common genetic disorders. Researchers are hunting for the genetic mutations that cause these disorders and developing tests to screen for them.
Table 2 Genetic Disorders and Their Mechanism of Inheritance
Disorder: Alkaptonuria the accumulation of alkapton in the body Adverse health effects: kidney stones, damage to cartilage Mechanism of inheritance: recessive allele
Disorder: cystic fibrosis causes the body to produce thick, sticky mucus that clogs the lungs and pancreatic duct Adverse health effects: infections; blocks the release of enzymes from the pancreas Mechanism of inheritance: recessive allele
Disorder: galactosemia the inability to digest galactose Adverse health effects: infants experience jaundice, failure to thrive, vomiting, and diarrhea; may lead to death if undiagnosed Mechanism of inheritance: recessive allele
Disorder: Hemophilia body cannot form blood clots Adverse health effects: excessive bleeding Mechanism of inheritance: recessive allele
Disorder: Lesch—Nyhan syndrome buildup of uric acid in the body Adverse health effects: gout, kidney problems, self-injuring behaviour Mechanism of inheritance: recessive allele
Disorder: Phenylketonuria accumulation of phenylalanine in blood Adverse health effects: poor mental development and growth, weak tooth enamel Mechanism of inheritance: recessive allele
Disorder: Tay—Sachs disease nerve cells in the brain are affected by the accumulation of gangliosides Adverse health effects: deterioration of muscle and physical abilities Mechanism of inheritance: recessive allele
Disorder: Huntington's disease progressive, irreversible degeneration of nervous system Adverse health effects: loss of muscle control and cognitive abilities Mechanism of inheritance: dominant allele
Disorder: Hypercholesterolemia high levels of cholesterol accumulate in the blood Adverse health effects: premature heart disease Mechanism of inheritance: dominant allele
Disorder: Neurofibromatosis nerve cells grow tumours Adverse health effects: tumours may be harmless or may cause damage by pushing on other nerves Mechanism of inheritance: dominant allele
Print Page 207
Ontario's Newborn Screening Program
In Ontario, newborns are currently screened for at least 28 genetic disorders. These disorders include cystic fibrosis, a number of metabolic disorders such as PKU, blood disorders including sickle-cell anemia, and disorders of the endocrine system. Even babies from families with no known history of these rare disorders are at risk.
Each year more than 140 000 newborns are tested, and of these, approximately 150 test positive for one of these rare genetic disorders. A positive result indicates the baby may have a genetic disorder. Only further genetic testing will confirm the presence or absence of a disease. Babies with one of these disorders often appear normal at birth but without early diagnosis may suffer irreversible damage and even death. Early diagnosis enables doctors to begin treatments that may eliminate or reduce serious health consequences and prevent infant death.
Key
K/U: Knowledge and Understanding T/I: Thinking and Investigation C: Communication A: Application
5.5 Summary
- Cystic fibrosis is a common, fatal disease passed on through a recessive mutated gene.
- Genetic counsellors construct pedigree charts and interpret results of genetic tests.
- Genetic screening is a means by which the presence of a mutated copy of a gene can be detected.
- Individuals who have the BRCA1 or BRCA2 gene mutation have a higher chance of developing breast cancer.
- Ontario's newborn screening program is used to test for many genetic disorders, including phenylketonuria and cystic fibrosis.
5.5 Questions
1. What factors may shorten the lives of people who have cystic fibrosis? K/U
2. Some people with cystic fibrosis find that athletic exercise helps their condition and keeps them in better health. Research and compare the stories of some people with CF who have become notable athletes. [GO TO NELSON SCIENCE] C A
3. Why is it important for infants to be genetically screened for PKU (phenylketonuria) at birth? K/U
4. Choose one of the disorders listed in Table 2. Use the Internet and other resources to research the following aspects of the disorder: [GO TO NELSON SCIENCE] A
(a) symptoms (b) frequency of the disorder in the general population or a specific population (c) research currently being conducted (d) existence of any genetic tests or screening mechanisms available for the disorder (e) treatment of the disorder
5. Does the presence of a defective BRCA1 or BRCA2 gene in a woman's genes guarantee that she will develop breast cancer? Why or why not? K/U
6. Using your guidance department, the Internet, and other sources, research the educational background an individual must have in order to become a genetic counsellor. [GO TO NELSON SCIENCE] C A
7. Use the Internet and other sources to learn more about the Newborn Screening Ontario (NSO) program. [GO TO NELSON SCIENCE] K/U
(a) Where in Ontario are the actual genetic tests conducted? (b)In addition to helping the newborn, for what other purposes can NSO results be used? (c) How old is the baby when the blood sample is taken? (d) The NSO program is mandatory for all newborns. Why do you think this policy was put in place?
Many human disorders have a genetic component, but the onset of a disorder may vary depending on life conditions. Some disorders can be detected at birth, while others do not manifest themselves until an individual has reached a certain age range. Some disorders can be treated and managed, while others lead to debilitating symptoms and premature death. Research geneticists spend a great deal of time and money to better understand the genetic components of such disorders. Their ultimate goal is to detect, prevent, or fix the genetic component of these disorders.
Cystic Fibrosis
Cystic fibrosis (CF) is the most common fatal genetic disease in Canada. The life expectancy for individuals with CF is less than 40 years, though this is increasing every year—some individuals with CF have lived into their seventies. The disease causes the body to produce thick, sticky mucus that clogs the lungs, leads to infections, and blocks the release of enzymes from the pancreas. The pancreas produces digestive enzymes that help break down protein, fats, and carbohydrates during digestion, so children and adults who have CF must take a large number of replacement enzymes daily in pill form. In addition, individuals with cystic fibrosis must undergo physical therapy or other treatments every day to help loosen accumulated mucus in the lungs (Figure 1). [GOT TO NELSON SCIENCE]
Figure 1 A child undergoing physical therapy for cystic fibrosis. The child's chest or back is tapped repeatedly to loosen the mucus in the lungs. This makes it easier for the child to rid his body of the mucus.
Cystic fibrosis is the result of a mutation, or a change in the genetic code. The first such defective gene was isolated and identified in 1989 by research geneticist Dr. Lap-chee Tsui and his team at the Hospital for Sick Children in Toronto. The mutated copy of the gene is recessive, so a child must inherit both copies of the defective allele from his or her parents in order to express CF. In the past, parents realized that they were carriers only when their child was born with CF.
mutation a change in the genetic code of an allele; the change may have a positive effect, a negative effect, or no effect
Today, carrier testing is used to identify individuals who carry disorder-causing recessive genes that may be inherited by their children. In fact, the Canadian College of Medical Geneticists recommends that carrier testing for cystic fibrosis be available to anyone who has a family history of CF. Genetic counsellors work with couples that have an increased risk of conceiving a child with CF.
carrier testing: a genetic test that determines whether an individual is heterozygous for a given gene that results in a genetic disorder
Testing for the presence of the mutated gene in the genome is known as genetic screening. Currently, we are aware of approximately 200 mutations that lead to cystic fibrosis. The severity of symptoms depends on which DNA mutation an individual has. The genetic test is based on a blood sample that is sent to a molecular diagnostic laboratory. In Canada the test is able to detect approximately 85 % of CF mutations. Table 1 shows the probability of conceiving a child with CF according to different test result scenarios.
genetic screening: tests used to identify the presence of a defective allele that leads to a genetic disorder
CAREER LINK
Pulmonologist
A pulmonologist is a physician who specializes in respiratory diseases. To learn more about a career in pulmonology, GO TO NELSON SCIENCE
Table 1 Risk of Having a Child with Cystic Fibrosis before and after Carrier
Testing in Canada
Test status of parents: No test performed
Risk of having a child with CF: 1 in 2500
Test status of parents: Both partners tested: results show one positive, one negative
Risk of having a child with CF: 1 in 600
Test status of parents: Both partners tested: results show both positive
Risk of having a child with CF: 1 in 4
Source: Canadian Cystic Fibrosis Foundation, Carrier Testing for Cystic Fibrosis
From Mendel's Punnett square for a recessive autosomal trait, we know that the probability of two heterozygous parents (Ff and Ff) conceiving a child with CF (ff) is 25 %, a child who is a carrier (Ff) is 50 %, and a child who does not carry the mutation (FF) is 25 % (Figure 2). Therefore, if both parents have tested positive for the mutation, the probability of giving birth to a child with CF is 1/4, as indicated in Table 1.
Figure 2 The probability of these two parents conceiving a child who does not express cystic fibrosis is 75 %.
Image: A grid square. Over top of the grid square is Ff. On top of the top left square is F, and on top of the top right square is f. On the left side of the grid square is Ff. On the side of the top left square is F, and on the side of the bottom left square is f. The top left square is labeled FF, the top right square is labeled Ff, the bottom left square is labeled Ff, anf the bottom right square is labeled ff.
Print Page 205
Key
K/U: Knowledge and Understanding
T/I: Thinking and Investigation
C: Communication
A: Application
Research This
Life with a Genetic Condition
Skills: Researching, Analyzing, Evaluating, Communicating
SKILLS HANDBOOK A2.1, A5.1
Cystic fibrosis is a genetic condition that can be managed by a variety of therapies and lifestyles. In the past people with CF barely lived past childhood. Today, with treatment and healthy lifestyle choices, many people with CF live well into adulthood. They can go to school, pursue careers, play sports, and have families. Some individuals with CF even live to be senior citizens. With advances in genetics, it is quite reasonable to think that a child born with CF today may live to see a cure for the disorder.
1. Use the Internet and other resources to find stories about people who have cystic fibrosis.
2. Make a list of strategies that individuals with CF use to manage their condition. Research and record the ways each person's strategy helps him or her as stated by that individual.
A. What similarities do the strategies share? A
B. Think about how each person's strategies would fit into your daily life, if you had CE Describe in paragraph form how your daily schedule would change. Do you think some CF strategies could fit easily into your own lifestyle? What changes would you have to make? What would stay the same? C A
Breast Cancer
Not all genetic disorders appear right from the onset of life. As you learned in Section 5.4, Huntington's disease does not usually show up until an individual is at least middle-aged. At this point, the potentially harmful allele may have been passed on to offspring. Cancer genes also fall into this category. Cancer is uncontrolled cell division.
BRCA1 and BRCA2 are human genes that belong to a class of genes known as tumour suppressors. Tumour suppressors produce chemicals that inhibit the growth of tumours in the body. If a woman carries a defective copy of either of these genes, she has an increased chance of developing breast or ovarian cancer at an early age.
Not all breast cancers are caused by a mutation in the BRCA1 or BRCA2 gene. A woman has a 12 % chance of developing breast cancer if she does not carry a copy of one of the defective genes, but a chance of 60 % if she is a carrier of even a single copy of either the defective BRCA1 or BRCA2 genes. The environment plays a significant role in determining whether cancer genes are turned on or off. For example, a woman who is exposed to estrogen-mimicking chemicals found in some lawn pesticides and certain types of plastics has a greater chance of developing breast cancer. [GO TO NELSON SCIENCE]
A woman who has a family history of breast cancer may choose to undergo genetic screening for the mutated BRCA1 or BRCA2 gene. If she does have a mutation, she may decide to have a mastectomy, a procedure that involves the removal of part or all of the breast tissue. Alternatively, she may choose to increase surveillance of her breast and ovarian health.
WEB LINK
For more information on estrogen-leaching plastics, GO TO NELSON SCIENCE
Phenylketonuria
Breast cancer and cystic fibrosis are potentially fatal conditions caused by a mutation in a gene. In contrast, individuals with phenylketonuria (PKU) are able to live normal lives with modifications to their lifestyle.
Phenylketonuria is a genetic disorder in which the affected individual is unable to utilize the amino acid phenylalanine, which the body needs in order to make proteins and essential brain chemicals. In Canada, about 1 in 20 000 people have PKU. Individuals with PKU do not possess the enzyme that breaks down phenylalanine
phenylketonuria (PKU) an autosomal, recessive, inherited genetic disorder that results in the accumulation of phenylalanine in the tissues and blood
Print Page 206
(found in most foods), and it accumulates in the blood and tissue. The brain function of a child with PKU does not develop normally.
Phenylketonuria is a recessive trait. Both parents must be carriers of the defective allele in order to pass it down to the child. Unlike for cystic fibrosis, researchers have not isolated the phenylketonuria gene. Hence prospective parents cannot be counselled or tested for the probability of producing a PKU child. Instead, every newborn is screened for the presence of PKU.
When a baby is about three days old, a few drops of its blood are tested for elevated amounts of phenylalanine and other compounds that are associated with genetic disorders. If the test is positive, more tests are performed to confirm or rule out PKU. If the infant does suffer from PKU, he or she must follow a diet that severely limits intake of high-protein foods such as meat, fish, eggs, and milk. If the diet is followed, the child will be able to lead a normal life. If PKU is left untreated, the child will suffer arrested mental development, decreased body growth, and poor development of tooth enamel.
Other Disorders
Table 2 summarizes some common genetic disorders. Researchers are hunting for the genetic mutations that cause these disorders and developing tests to screen for them.
Table 2 Genetic Disorders and Their Mechanism of Inheritance
Disorder: Alkaptonuria the accumulation of alkapton in the body
Adverse health effects: kidney stones, damage to cartilage
Mechanism of inheritance: recessive allele
Disorder: cystic fibrosis causes the body to produce thick, sticky mucus that clogs the lungs and pancreatic duct
Adverse health effects: infections; blocks the release of enzymes from the pancreas
Mechanism of inheritance: recessive allele
Disorder: galactosemia the inability to digest galactose
Adverse health effects: infants experience jaundice, failure to thrive, vomiting, and diarrhea; may lead to death if undiagnosed
Mechanism of inheritance: recessive allele
Disorder: Hemophilia body cannot form blood clots
Adverse health effects: excessive bleeding
Mechanism of inheritance: recessive allele
Disorder: Lesch—Nyhan syndrome buildup of uric acid in the body
Adverse health effects: gout, kidney problems, self-injuring behaviour
Mechanism of inheritance: recessive allele
Disorder: Phenylketonuria accumulation of phenylalanine in blood
Adverse health effects: poor mental development and growth, weak tooth enamel
Mechanism of inheritance: recessive allele
Disorder: Tay—Sachs disease nerve cells in the brain are affected by the accumulation of gangliosides
Adverse health effects: deterioration of muscle and physical abilities
Mechanism of inheritance: recessive allele
Disorder: Huntington's disease progressive, irreversible degeneration of nervous system
Adverse health effects: loss of muscle control and cognitive abilities
Mechanism of inheritance: dominant allele
Disorder: Hypercholesterolemia high levels of cholesterol accumulate in the blood
Adverse health effects: premature heart disease
Mechanism of inheritance: dominant allele
Disorder: Neurofibromatosis nerve cells grow tumours
Adverse health effects: tumours may be harmless or may cause damage by pushing on other nerves
Mechanism of inheritance: dominant allele
Print Page 207
Ontario's Newborn Screening Program
In Ontario, newborns are currently screened for at least 28 genetic disorders. These disorders include cystic fibrosis, a number of metabolic disorders such as PKU, blood disorders including sickle-cell anemia, and disorders of the endocrine system. Even babies from families with no known history of these rare disorders are at risk.
Each year more than 140 000 newborns are tested, and of these, approximately 150 test positive for one of these rare genetic disorders. A positive result indicates the baby may have a genetic disorder. Only further genetic testing will confirm the presence or absence of a disease. Babies with one of these disorders often appear normal at birth but without early diagnosis may suffer irreversible damage and even death. Early diagnosis enables doctors to begin treatments that may eliminate or reduce serious health consequences and prevent infant death.
Key
K/U: Knowledge and Understanding
T/I: Thinking and Investigation
C: Communication
A: Application
5.5 Summary
- Cystic fibrosis is a common, fatal disease passed on through a recessive mutated gene.
- Genetic counsellors construct pedigree charts and interpret results of genetic tests.
- Genetic screening is a means by which the presence of a mutated copy of a gene can be detected.
- Individuals who have the BRCA1 or BRCA2 gene mutation have a higher chance of developing breast cancer.
- Ontario's newborn screening program is used to test for many genetic disorders, including phenylketonuria and cystic fibrosis.
5.5 Questions
1. What factors may shorten the lives of people who have cystic fibrosis? K/U
2. Some people with cystic fibrosis find that athletic exercise helps their condition and keeps them in better health. Research and compare the stories of some people with CF who have become notable athletes. [GO TO NELSON SCIENCE] C A
3. Why is it important for infants to be genetically screened for PKU (phenylketonuria) at birth? K/U
4. Choose one of the disorders listed in Table 2. Use the Internet and other resources to research the following aspects of the disorder: [GO TO NELSON SCIENCE] A
(a) symptoms
(b) frequency of the disorder in the general population or a specific population
(c) research currently being conducted
(d) existence of any genetic tests or screening mechanisms available for the disorder
(e) treatment of the disorder
5. Does the presence of a defective BRCA1 or BRCA2 gene in a woman's genes guarantee that she will develop breast cancer? Why or why not? K/U
6. Using your guidance department, the Internet, and other sources, research the educational background an individual must have in order to become a genetic counsellor. [GO TO NELSON SCIENCE] C A
7. Use the Internet and other sources to learn more about the Newborn Screening Ontario (NSO) program. [GO TO NELSON SCIENCE] K/U
(a) Where in Ontario are the actual genetic tests conducted?
(b)In addition to helping the newborn, for what other purposes can NSO results be used?
(c) How old is the baby when the blood sample is taken?
(d) The NSO program is mandatory for all newborns. Why do you think this policy was put in place?