NU 545 UNIT 7 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED
Describe the specific chromosomal abnormality responsible for Down Syndrome
The most well known aneuploidy (those that do not contain a multiple of 23 chromosomes) in an
autosome is trisomy of the 21st chromosome. J. Langdon Down 1st described the the disease in 1866.
Down syndrome is seen in 1 in 800 births. IQ's between 25 and 70. Facial features: low nasal bridge,
epicentral folds, protruding tongue, and flat low set ears. Congenital heart defects in 1/3 to 1/2 of live
born children. Decreased ability to fight respiratory conditions and an increased susceptibility to
leukemia. By age 40 symptoms resembling Alzheimer develop. 97% of Down Syndrome's cases are
caused by nondisjunction during the formation of one of the parent's gametes or during early embryonic
development. 3% from translocations. Risk increases with maternal age.
Causes of mental retardation.
Chromosomal abnormalities.
What gene abnormality causes cystic fibrosis?
Like autosomal dominant diseases, those caused by autosomal recessive alleles are rare in populations,
although the number of carriers for recessive diseases can be high. The most common lethal recessive
disease in white children, cystic fibrosis, occurs in about 1 in 2500 births. Approximately 1 in 25 whites
carries one copy of an allele that can cause cystic fibrosis (see Chapter 36). Because an individual must
be homozygous for a recessive allele to express thedisease, the carriers are phenotypically normal.
,Because most recessive alleles are maintained innormal carriers, they are able to survive in the
population from one generation to the next. As with many autosomal dominant diseases, many
autosomal recessive diseases are characterized by delayed age of onset, incomplete penetrance, and
variable expressivity.
How is a recessive gene inherited?
Autosomal recessive diseases occur when both parents are carriers of the same disease and their child
inherits an altered gene from each of them. Children of carrier parents have:A 25% chance of inheriting
two altered genes and developing the disease.
Inheritance of Hemophilia A?
Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with
these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males
(who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the
condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of
the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this
gene, it is very rare for females to have hemophilia. A characteristic of X-linked inheritance is that fathers
cannot pass X-linked traits to their sons.
Inheritance of Hemophilia A?
In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a
carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor
IX, which is generally enough for normal blood clotting. However, about 10 percent of carrier females
have less than half the normal amount of one of these coagulation factors; these individuals are at risk
for abnormal bleeding, particularly after an injury, surgery, or tooth extraction.
,Risk factors for DM II; why is obesity an important risk factor for DM II?
An important risk factor is TCF7L2 which encodes a transcription factor involved in the secretion of
insulin. Another association has been found between a common allele of the gene that incomes
peroxisome proliferator-activated receptor gamma (PPAR-y), a nuclear receptor that is involved in
adipocyte differentiation and glucose metabolism. This receptor is the target of thiazolidinediones
(TZD's) a class of drugs commonly used to increase insulin sensitivity in those with type 2 diabetes. The 2
most important risk factors for DM II are positive family history and obesity; the latter increases insulin
resistance.
Definition of carcinoma
Cancer arising from in epithelial cells
How do cancer cells gain access to the circulation?
cells gain access to circulation through new tumor-associated blood vessels or angiongesis
Mobile tumor cells are able to enter circulation (leakly newsly made blood vessels)
once in circulation, cells must be able to withstand the physiological stress of travel in the blood and
lymphatic circulation
Sometimes they bind to blood platelets=protect themselves
What is adjuvant chemotherapy?
Adjuvant chemotherapy is an approach to fighting cancer that combines different forms of healing.
Chemotherapy and radiation, or chemotherapy and surgery are used together. Usually the
chemotherapy will be used after all of the known and visible cancer has been removed surgically or with
radiation. Adjuvant chemotherapy aims to destroy hidden cancer cells that remain but are undetectable.
Adjuvant means additional. Adjuvant chemotherapy is given to patients after primary treatment, when
, the doctor thinks there is a high risk the cancer will return. After a primary treatment of surgery or
radiation, adjuvant chemotherapy reduces the risk of recurrence. The elimination of undetectable
microscopic cancer cells that may have traveled to other parts of the body is the goal of adjuvant
chemotherapy.
When adjuvant chemotherapy doesn't result in a full cure it does make the intervals between a cancer
relapse longer. Adjuvant chemotherapy typically begins within three to five weeks of the surgical
removal of the cancer and has different treatment lengths depending on the cancer. For breast cancer,
the adjuvant chemotherapy is administered for three to nine months. In the case of colon cancer,
treatment rarely last more than six months.
Most common time childhood cancers are diagnosed?
Childhood and adolescent cancers are often associated with specific peak times of physical growth and
may occur as a consequence altered cellular regulatory mechanisms at a given time in the child or
adolescents development. Embryonal tumors most often develop before the age of 5 years, acute
lymphoblastic leukemia occurs most often in younger children, and bone tumors occur most often in
adolescents.
DES exposure prenatally
Diethylstibestrol (DES) which was prescribed by physicians to treat spontaneous miscarriage. Identified
as a transplacental chemical carcinogen because a small percentage of the daughters of the women who
took DES developed adenocarcinomas or the vagina and cervix.
Where do most childhood cancers arise from?
WITH COMPLETE SOLUTIONS VERIFIED
Describe the specific chromosomal abnormality responsible for Down Syndrome
The most well known aneuploidy (those that do not contain a multiple of 23 chromosomes) in an
autosome is trisomy of the 21st chromosome. J. Langdon Down 1st described the the disease in 1866.
Down syndrome is seen in 1 in 800 births. IQ's between 25 and 70. Facial features: low nasal bridge,
epicentral folds, protruding tongue, and flat low set ears. Congenital heart defects in 1/3 to 1/2 of live
born children. Decreased ability to fight respiratory conditions and an increased susceptibility to
leukemia. By age 40 symptoms resembling Alzheimer develop. 97% of Down Syndrome's cases are
caused by nondisjunction during the formation of one of the parent's gametes or during early embryonic
development. 3% from translocations. Risk increases with maternal age.
Causes of mental retardation.
Chromosomal abnormalities.
What gene abnormality causes cystic fibrosis?
Like autosomal dominant diseases, those caused by autosomal recessive alleles are rare in populations,
although the number of carriers for recessive diseases can be high. The most common lethal recessive
disease in white children, cystic fibrosis, occurs in about 1 in 2500 births. Approximately 1 in 25 whites
carries one copy of an allele that can cause cystic fibrosis (see Chapter 36). Because an individual must
be homozygous for a recessive allele to express thedisease, the carriers are phenotypically normal.
,Because most recessive alleles are maintained innormal carriers, they are able to survive in the
population from one generation to the next. As with many autosomal dominant diseases, many
autosomal recessive diseases are characterized by delayed age of onset, incomplete penetrance, and
variable expressivity.
How is a recessive gene inherited?
Autosomal recessive diseases occur when both parents are carriers of the same disease and their child
inherits an altered gene from each of them. Children of carrier parents have:A 25% chance of inheriting
two altered genes and developing the disease.
Inheritance of Hemophilia A?
Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with
these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males
(who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the
condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of
the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this
gene, it is very rare for females to have hemophilia. A characteristic of X-linked inheritance is that fathers
cannot pass X-linked traits to their sons.
Inheritance of Hemophilia A?
In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a
carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor
IX, which is generally enough for normal blood clotting. However, about 10 percent of carrier females
have less than half the normal amount of one of these coagulation factors; these individuals are at risk
for abnormal bleeding, particularly after an injury, surgery, or tooth extraction.
,Risk factors for DM II; why is obesity an important risk factor for DM II?
An important risk factor is TCF7L2 which encodes a transcription factor involved in the secretion of
insulin. Another association has been found between a common allele of the gene that incomes
peroxisome proliferator-activated receptor gamma (PPAR-y), a nuclear receptor that is involved in
adipocyte differentiation and glucose metabolism. This receptor is the target of thiazolidinediones
(TZD's) a class of drugs commonly used to increase insulin sensitivity in those with type 2 diabetes. The 2
most important risk factors for DM II are positive family history and obesity; the latter increases insulin
resistance.
Definition of carcinoma
Cancer arising from in epithelial cells
How do cancer cells gain access to the circulation?
cells gain access to circulation through new tumor-associated blood vessels or angiongesis
Mobile tumor cells are able to enter circulation (leakly newsly made blood vessels)
once in circulation, cells must be able to withstand the physiological stress of travel in the blood and
lymphatic circulation
Sometimes they bind to blood platelets=protect themselves
What is adjuvant chemotherapy?
Adjuvant chemotherapy is an approach to fighting cancer that combines different forms of healing.
Chemotherapy and radiation, or chemotherapy and surgery are used together. Usually the
chemotherapy will be used after all of the known and visible cancer has been removed surgically or with
radiation. Adjuvant chemotherapy aims to destroy hidden cancer cells that remain but are undetectable.
Adjuvant means additional. Adjuvant chemotherapy is given to patients after primary treatment, when
, the doctor thinks there is a high risk the cancer will return. After a primary treatment of surgery or
radiation, adjuvant chemotherapy reduces the risk of recurrence. The elimination of undetectable
microscopic cancer cells that may have traveled to other parts of the body is the goal of adjuvant
chemotherapy.
When adjuvant chemotherapy doesn't result in a full cure it does make the intervals between a cancer
relapse longer. Adjuvant chemotherapy typically begins within three to five weeks of the surgical
removal of the cancer and has different treatment lengths depending on the cancer. For breast cancer,
the adjuvant chemotherapy is administered for three to nine months. In the case of colon cancer,
treatment rarely last more than six months.
Most common time childhood cancers are diagnosed?
Childhood and adolescent cancers are often associated with specific peak times of physical growth and
may occur as a consequence altered cellular regulatory mechanisms at a given time in the child or
adolescents development. Embryonal tumors most often develop before the age of 5 years, acute
lymphoblastic leukemia occurs most often in younger children, and bone tumors occur most often in
adolescents.
DES exposure prenatally
Diethylstibestrol (DES) which was prescribed by physicians to treat spontaneous miscarriage. Identified
as a transplacental chemical carcinogen because a small percentage of the daughters of the women who
took DES developed adenocarcinomas or the vagina and cervix.
Where do most childhood cancers arise from?
