BACHELOR OF SCIENCE IN NURSING:

CARE OF MOTHER AND CHILD AT RISK OR

WITH PROBLEMS (ACUTE AND CHRONIC):
COURSE MODULE COURSE UNIT WEEK
1 1 1

Genetic Assessment and Counselling

Read course and unit objectives

Read study guide prior to class attendance
Read and understand required learning
resources; refer to unit terminologies for jargons
Proactively participate in online discussions
Participate in weekly discussion board (Canvas)
Answer and submit course unit tasks

At the end of this unit, the students are expected to:

Cognitive:
1. Describe the nature of inheritance, patterns of recessive and dominant mendelian inheritance,
and common chromosomal aberrations that cause physical or cognitive disorders.
2. Identify National Health Goals related to genetic disorders.
 3. Use critical thinking to analyze ways that can make genetic assessment or education more
family centered.
4. Integrate knowledge of genetic inheritance with nursing process to achieve quality maternal
and child health nursing care.
Affective:
• Listen attentively during class discussions
• Demonstrate tact and respect when challenging other people’s opinions and ideas
• Accept comments and reactions of classmates on one’s opinions openly and graciously.
• Develop heightened interest in studying Maternal and Child Nursing.
Psychomotor:
1. Participate actively during online class discussions and group activities
2. Express opinion and thoughts in online classes

Flagg (2018). Maternal and Child Health Nursing: Care of the Childbearing and Childrearing Family.
Wolters Kluwer.

National Health Situation on MCN

The maternal and child population is constantly changing because of changes in social structure,
variations in family lifestyle, and changing patterns of illness. Client advocacy, participating in cost-
containment measures, focusing on health education, and creating new nursing roles are ways in which
nurses have adapted to these changes. Client advocacy is safeguarding and advancing the interests of
clients and their families. The role includes knowing the health care services available in a community,
establishing a relationship with families, and helping them make informed choices about what course of
action or service would be best for them.
National health goals are intended to help citizens more easily understand the importance of health
promotion and disease prevention and to encourage wide participation in improving health in the next
decade. It is important for maternal and child health nurses to be familiar with these goals because nurses
play such a vital role in helping the nation achieve these objectives through both practice and research.
The goals also serve as the basis for grant funding and financing of evidence-based practice.
Focus on National Health Goals (Leading Health Indicators):
• Physical Activity ● Mental Health
• Overweight and Obesity ● Injury and Violence
• Tobacco use ● Environmental Quality
• Substance abuse ● Immunization
• Responsible sexual behavior ● Access to Health Care
Genetic Disorders
Inherited or genetic disorders are disorders that can
be passed from one generation to the next. They
result from some disorder in gene or chromosome
structure and occur in 5% to 6% of newborns.
Genetics is the study of the way such disorders
occur. Cytogenetics is the study of chromosomes by
light microscopy and the method by which
chromosomal aberrations are identified. Genetic
disorders may occur when an ovum and sperm fuse
or even earlier, in the meiotic division phase of the
gametes (ovum and sperm). Some genetic
abnormalities are so severe that normal fetal growth
cannot continue past that point. This early cell
division is so precarious a process, in fact, that up
to 50% of first-trimester spontaneous miscarriages
may be the result of chromosomal abnormalities.
Other genetic disorders do not affect life in utero, so
the result of the disorder becomes apparent only at
the time of fetal testing or after birth. Women having
in vitro fertilization (IVF) can have both the egg and
sperm examined for genetic disorders of single
gene or chromosome concerns before implantation.

Nature of Inheritance
Genes are the basic units of heredity that determine both the physical and cognitive characteristics
of people. Composed of segments of DNA (deoxyribonucleic acid), they are woven into strands in the
nucleus of all body cells to form chromosomes. In humans, each cell, except for the sperm and ovum,
contains 46 chromosomes (22 pair of autosomes and 1 pair of sex chromosomes). Spermatozoa and
ova each carry only half of the chromosome number, or 23 chromosomes. For each chromosome in
the sperm cell, there is a like chromosome of similar size and shape and function (autosome, or
homologous chromosome) in the ovum. Because genes are always located at fixed positions on
chromosomes, two like genes (alleles) for every trait are represented in the ovum and sperm on
autosomes. The one chromosome in which this does not occur is the chromosome for determining
gender. If the sex chromosomes are both type X (large symmetric) in the zygote formed from the
union of a sperm and ovum, the individual is female. If one sex chromosome is an X and one a Y (a
smaller type), the individual is a male. A person’s phenotype refers to his or her outward appearance
or the expression of genes. A person’s genotype refers to his or her actual gene composition. It is
impossible to predict a person’s genotype from the phenotype, or outward appearance. A person’s
genome is the complete set of genes present (about 50,000 to 100,000). A normal genome is
abbreviated as 46XX or 46XY (designation of the total number of chromosomes plus a graphic
description of the sex chromosomes present).

Mendelian Inheritance: Dominant and Recessive Patterns

A person who has two like genes for a trait—two healthy genes, for example (one from the mother
and one from the father)—on two like chromosomes is said to be homozygous for that trait. If the
genes differ (a healthy gene from the mother and an unhealthy gene from the father, or vice versa),
the person is said to be heterozygous for that trait. Many genes are dominant in their action over
others. When paired with nondominant (recessive) genes, dominant genes. are always expressed in
preference to the recessive genes. An individual with two homozygous genes for a dominant trait is
said to be homozygous dominant; an individual with two genes for a recessive trait is homozygous
recessive.

Inheritance of Disease
1. Autosomal Dominant Disorders
With an autosomal dominant condition, either a
person has two unhealthy genes (is homozygous
dominant) or is heterozygous, with the gene causing
the disease stronger than the corresponding healthy
recessive gene for the same trait. If a person who is
heterozygous for an autosomal dominant trait (the
usual pattern) mates with a person who is free of the
trait, the chances are even (50%) that a child born
to the couple would have the disorder or would be
disease and carrier free (i.e., carrying no affected
gene for the disorder). Two heterozygous people
with a dominantly inherited disorder are unlikely to
choose each other as reproductive partners. If they
do, however, their chances of having children free
from the disorder decline. There would be only a
25% chance of a child’s being disease and carrier
free, a 50% chance that the child would have the
disorder as both parents do, and a 25% chance that
a child would be homozygous dominant (i.e., have
two dominant disorder genes), a condition that probably would be incompatible with life.
In assessing family genograms (maps of family relationships) for the incidence of inherited
disorders, a few common findings are usually discovered when a dominantly inherited pattern
is present in a family:
• One of the parents of a child with the disorder also will have the disorder (a vertical
transmission picture).
• The sex of the affected individual is unimportant in terms of inheritance.
• There is usually a history of the disorder in other family members.
2. Autosomal Recessive Inheritance
These inheritances tend to be biochemical or enzymatic. Such diseases do not occur unless
two genes for the disease are present. Examples include cystic fibrosis, adrenogenital
syndrome, albinism, Tay-Sachs disease, galactosemia, phenylketonuria, limb-girdle muscular
dystrophy, and Rh factor incompatibility.
When family genograms are assessed for the incidence of inherited disease, situations
commonly discovered when a recessively inherited disease is present in the family include:
 • Both parents of a child with the disorder
are clinically free of the disorder.
• The sex of the affected individual is
unimportant in terms of inheritance.
• The family history for the disorder is
negative—that is, no one can identify
anyone else who had it (a horizontal
transmission pattern).
• A known common ancestor between the
parents sometimes exists. This explains
how both male and came to possess a
like gene for the disorder.
3. X-Linked Dominant Inheritance
Some genes for disorders are located on, and therefore transmitted only by, the female sex
chromosome (the X chromosome). If the affected gene is dominant, only one X chromosome
with the trait need be present for symptoms of the disorder to be manifested. Family
characteristics seen with this type of inheritance usually include:
• All individuals with the gene are affected
(the gene is dominant).
• All female children of affected men are
affected; all male children of affected
men are unaffected.
• It appears in every generation.
• All children of homozygous affected
women are affected. Fifty percent of the
children of heterozygous affected
women are affected.
4. X-Linked Recessive Inheritance
Most X-linked inherited disorders are not
dominant, but recessive. When the inheritance
of a recessive gene comes from both parents
(homozygous recessive) it appears to be
incompatible with life. Therefore, females who
inherit the affected gene will be heterozygous,
and, because a normal gene is also present,
the expression of the disease will be blocked.
On the other hand, because males have only
one X chromosome, the disease will be
manifested in any male children who receive
the affected gene from their mother.
Hemophilia A and Christmas disease (blood-
factor deficiencies), color blindness, Duchenne
(pseudohypertrophic) muscular dystrophy, and
fragile X syndrome (a cognitive challenge
 syndrome) are examples of this type of inheritance. In this inheritance pattern, the mother has
the affected gene on one of her X chromosomes and the father is disease-free. When this
occurs, the chances are 50% that a male child will manifest the disease and 50% that a female
child will carry the disease gene. If the father has the disease and chooses a sexual partner
who is free of the disease gene, the chances are 100% that a daughter will have the sex-
linked recessive gene, but there is no chance that a son will have the disease. When X-linked
recessive inheritance is present in a family, a family genogram will reveal:
• Only males in the family will have the disorder.
• A history of girls dying at birth for unknown reasons often exists (females who had the
affected gene on both X chromosomes).
• Sons of an affected man are unaffected.
• The parents of affected children do not have the disorder
5. Multifactorial (Polygenic) Inheritance
Many childhood disorders such as heart disease, diabetes, pyloric stenosis, cleft lip and
palate, neural tube disorders, hypertension, and mental illness tend to have a higher-than
usual incidence in some families. They appear to occur from multiple gene combinations
possibly combined with environmental factors. Diseases caused by multiple factors this way
do not follow Mendelian laws because more than a single gene or HLA is involved. It may be
more difficult for parents to understand why these disorders occur because their incidence is
so unpredictable. A family history, for instance, may reveal no set pattern. Some of these
conditions have a predisposition to occur more frequently in one sex (cleft palate occurs more
often in girls than boys), but they can occur in either sex.
6. Imprinting
Imprinting refers to the differential expression of genetic material and allows researchers to
identify whether the chromosomal material has come from the male or female parent.

Chromosomal Abnormalities (cytogenic Disorders)

In some instances of genetic disease, the abnormality occurs not because of dominant or recessive
gene patterns but through a fault in the number or structure of chromosomes which results in missing
or distorted genes. When chromosomes are photographed and displayed, the resulting arrangement
is termed a karyotype. The number of chromosomes and specific parts of chromosomes can be
identified by karyotyping or by a process termed fluorescent in situ hybridization (FISH).
1. Nondisjunction Abnormalities
Meiosis is the type of cell division in which the number of chromosomes in the cell is reduced
to the haploid (half) number for reproduction (i.e., 23 rather than 46 chromosomes). All sperm
and ova undergo a meiosis cell division early in formation. During this division, half of the
chromosomes are attracted to one pole of the cell and half to the other pole. The cell then
divides cleanly, with 23 chromosomes in the first new cell and 23 chromosomes in the second
new cell. Chromosomal abnormalities occur if the division is uneven (nondisjunction). The
result may be that one new sperm cell or ovum has 24 chromosomes and the other has only
22. If a spermatozoon or ovum with 24 or 22 chromosomes fuses with a normal spermatozoon
or ovum, the zygote (sperm and ovum combined) will have either 47 or 45 chromosomes, not
the normal 46. The presence of 45 chromosomes does not appear to be compatible with life,
and the embryo or fetus probably will be aborted.
2. Deletion Abnormalities
 Deletion abnormalities are a form of chromosome disorder in which part of a chromosome
breaks during cell division, causing the affected person to have the normal number of
chromosomes plus or minus an extra portion of a chromosome.
3. Translocation Abnormalities
Translocation abnormalities are perplexing situations in which a child gains an additional
chromosome through another route. A form of Down syndrome occurs as an example of this.
In this instance, one parent of the child has the correct number of chromosomes (46), but
chromosome 21 is misplaced; it is abnormally attached to another chromosome, such as
chromosome 14 or 15. The parent’s appearance and functioning are normal because the total
chromosome count is a normal 46. He or she is termed a balanced translocation carrier. If,
during meiosis, this abnormal chromosome 14 (carrying the extra 21 chromosome) and a
normal chromosome 21 from the other parent are both included in one sperm or ovum, the
resulting child will have a total of 47 chromosomes because of the extra number 21. Such a
child is said to have an unbalanced translocation syndrome. The phenotype (appearance) of
the child will be indistinguishable from that of a child with the form of Down syndrome that
occurs from simple nondisjunction.
4. Mosaicism
Mosaicism is an abnormal condition that is present when the nondisjunction disorder occurs
after fertilization of the ovum, as the structure begins mitotic (daughter-cell) division. If this
occurs, different cells in the body will have different chromosome counts. The extent of the
disorder depends on the proportion of tissue with normal chromosome structure to tissue with
abnormal chromosome constitution.
5. Isochromosomes
If a chromosome accidentally divides not by a vertical separation but by a horizontal one, a
new chromosome with mismatched long and short arms can result. This is an isochromosome.
It has much the same effect as a translocation abnormality when an entire extra chromosome
exists.

Genetic Counselling
Any individual concerned about the possibility of transmitting a disease to his or her children should have
access to genetic counseling for advice on the inheritance of disease. Such counseling can serve to:
• Provide concrete, accurate information about the process of inheritance and inherited disorders.
• Reassure people who are concerned that their child may inherit a particular disorder that the
disorder will not occur.
• Allow people who are affected by inherited disorders to make informed choices about future
reproduction.
• Offer support to people who are affected by genetic disorders
Genetic counseling can result in making individuals feel “well” or free of guilt for the first time in their lives
if they discover that the disorder, they were worried about was not an inherited one but was rather a
chance occurrence. It is essential that information revealed in genetic screening be kept confidential,
because such information could be used to damage a person’s reputation or harm a future career or
relationship. This necessity to maintain confidentiality prevents health care providers from alerting other
family members about the inherited characteristic unless the member requesting genetic assessment
has given consent for the information to be revealed. In some instances, a genetic history reveals
information, such as that a child has been adopted or is the result of artificial insemination, or that a
current husband is not the child’s father information that a family doesn’t want revealed. The member of
the family seeking counseling has the right to decide whether this information may be shared with other
family members. The ideal time for counseling is before a first pregnancy. Some couples take this step
even before committing themselves to marriage so they can offer not to involve their partner in a marriage
if children of the marriage would be subject to a serious inherited disorder. Other couples first become
aware of the need for genetic counseling after the birth of a first child with a disorder. It is best if they
receive counseling before a second pregnancy. A couple may not be ready for this, however, until the
initial shock of their first child’s condition and the grief reaction that may accompany it have run their
course. Only then are they ready for information and decision making. Even if a couple decides not to
have any more children, it is important that they know that genetic counseling is available should their
decision change. Also be certain that they are aware that as their children reach reproductive age, they,
too, may benefit from genetic counseling. Couples who are most apt to benefit from a referral for genetic
testing or counseling include:
• A couple who has a child with a congenital disorder or an inborn error of metabolism. Many
congenital disorders occur because of teratogenic invasion during pregnancy that has gone
unrecognized. Learning that the abnormality occurred by chance rather than inheritance is
important, because the couple will not have to spend the remainder of their childbearing years in
fear that another child may be born with the disorder (although a chance circumstance could
occur again). If a definite teratogenic agent, such as a drug a woman took during pregnancy, can
be identified, the couple can be advised about preventing this occurrence in a future pregnancy.
• A couple whose close relatives have a child with a genetic disorder such as a translocation
disorder or an inborn error of metabolism. It is difficult to predict the expected occurrence of many
“familial” or multifactorial disorders. In these instances, counseling should be aimed at educating
the couple about the disorder, treatment available, and the prognosis or outcome of the disorder.
Based on this information, the couple can make an informed reproductive choice about children.
• Any individual who is a known balanced translocation carrier. Understanding of his or her own
chromosome structure and the process by which future children could be affected can help such
an individual make an informed choice about reproduction or can alert him or her to the
importance of fetal karyotyping during any future pregnancy.
• Any individual who has an inborn error of metabolism or chromosomal disorder. Any person with
a disease should know the inheritance pattern of the disease and, like those who are balanced
translocation carriers, should be aware if prenatal diagnosis is possible for his or her disorder.
• A consanguineous (closely related) couple. The more closely related are two people, the more
genes they have in common, so the more likely it is that a recessively inherited disease will be
expressed. A brother and sister, for example, have about 50% of their genes in common; first
cousins have about 12% of their genes in common.
• Any woman older than 35 years and any man older than 55 years. This is directly related to the
association between advanced parental age and the occurrence of Down syndrome.
• Couples of ethnic backgrounds in which specific illnesses are known to occur. Mediterranean
people, for example, have a high incidence of thalassemia, a blood disorder; those with a Chinese
ancestry have a high incidence of glucose-6- phosphate dehydrogenase (G6PD) deficiency, a
blood disorder where destruction of red cells can occur.

Nursing Responsibilities
Nurses play important roles in assessing for signs and symptoms of genetic disorders, in offering support
to individuals who seek genetic counseling, and in helping with reproductive genetic testing procedures
by such actions as:
1. Explaining to a couple what procedures they can expect to undergo.
2. Explaining how different genetic screening tests are done and when they are usually offered.
3. Supporting a couple during the wait for test results.
4. Assisting couples in values clarification, planning, and decision making based on test results.

Genetic Disorders Assessment

1. History
a. Obtain information and document diseases in family members for a minimum of three
generations. Remember to include half brothers and sisters or anyone related in any way
as family.
b. Document the mother’s age because some disorders increase in incidence with age.
c. Document also whether the parents are consanguineous or related to each other.
d. Documenting the family’s ethnic background can reveal risks for certain disorders that
occur more commonly in some ethnic groups than others. If the couple seeking
counseling is unfamiliar with their family history, ask them to talk to senior family members
about other relatives (grandparents, aunts, uncles) before they come for an interview.
Have them ask specifically for instances of spontaneous miscarriage or children in the
family who died at birth.
e. Extensive prenatal history of any affected person should be obtained to determine
whether environmental conditions could account for the condition.
2. Physical Assessment
a. A careful physical assessment of any family member with a disorder, child’s siblings, and
the couple seeking counseling is needed. It is possible for an individual to have a minimal
expression of a disorder that has gone previously undiagnosed.
b. During inspection, pay particular attention to certain body areas, such as the space
between the eyes; the height, contour, and shape of ears; the number of fingers and
toes, and the presence of webbing. Dermatoglyphics (the study of surface markings of
the skin) can also be helpful. Note any abnormal fingerprints or palmar creases as these
are present with some disorders. Abnormal hair whorls or coloring of hair can also be
present.
c. Careful inspection of newborns is often sufficient to identify a child with a potential
chromosomal disorder. Infants with multiple congenital anomalies, those born at less
than 35 weeks’ gestation, and those whose parents have had other children with
chromosomal disorders need extremely close assessment.
3. Diagnostic Testing
a. Karyotyping
A sample of peripheral venous blood or a scraping
of cells from the buccal membrane is taken. Cells
are allowed to grow until they reach metaphase,
the most easily observed phase. Cells are then
stained, placed under a microscope, and
photographed. Chromosomes are identified
according to size, shape, and stain; cut from the
 photograph, and arranged. Any additional, lacking, or abnormal chromosomes can be
visualized by this method. A newer method of staining, FISH, allows karyotyping to be
done immediately, rather than waiting for the cells to reach metaphase. This makes it
possible for a report to be obtained in only 1 day. Fetal skin cells can be obtained by
amniocentesis or CVS. A few fetal cells circulate in the maternal bloodstream, most
noticeably trophoblasts, lymphocytes, and granulocytes. They are present but few during
the first and second trimesters but plentiful during the third trimester. Such cells can be
cultured and used for genetic testing for such disorders as the trisomy.
b. Maternal Serum Screening
Alpha-fetoprotein (AFP) is a glycoprotein
produced by the fetal liver that reaches a
peak in maternal serum between the 13th
and 32nd week of pregnancy. Most
pregnant women have an MSAFP test
done routinely at the 15th week of
pregnancy. If the result is abnormal,
amniotic fluid is then assessed.
Unfortunately, the MSAFP test has a
false-positive rate of about 30% if the date
of conception is not well documented. Use
of a “triple study” (AFP, estriol, and hCG)
reduces this false-positive rate, although
false-positive reports still occur.
c. Chorionic Villi Sampling
CVS is a diagnostic technique that involves the retrieval and analysis of chorionic villi from
the growing placenta for chromosome or DNA analysis. The test is highly accurate and
yields no more false-positive results than does amniocentesis. Although this procedure
may be done as early as week 5 of pregnancy, it is more commonly done at 8 to 10 weeks.
With this technique, the chorion cells are located by ultrasound. A thin catheter is then
inserted vaginally, or a biopsy needle is inserted abdominally or intravaginally, and
several chorionic cells are removed for analysis. CVS carries a small risk (less than 1%)
of causing excessive bleeding, leading to pregnancy loss. After CVS, instruct a woman to
report chills or fever suggestive of infection or symptoms of threatened miscarriage
(uterine contractions or vaginal bleeding). Women with an Rh-negative blood type need
Rh immune globulin administration after the procedure to guard against isoimmunization
in the fetus. The cells removed in CVS are karyotyped or submitted for DNA analysis to
reveal whether the fetus has a genetic disorder. Because chorionic villi cells are rapidly
 dividing, results are available quickly, perhaps as soon as the next day. If a twin or multiple
pregnancy is present, with two or more separate placentas, cells should be removed
separately from each placenta. Because fraternal twins are derived from separate ova,
one twin could have a chromosomal abnormality while the other does not.
d. Amniocentesis
Amniocentesis is the withdrawal of amniotic
fluid through the abdominal wall for analysis at
the 14th to 16th week of pregnancy. Because
amniotic fluid has reached about 200 mL at this
point, enough fluid can be withdrawn for
karyotyping of skin cells found in the fluid as
well as an analysis of AFP or
acetylcholinesterase. For the procedure, a
pocket of amniotic fluid is located by
ultrasound. Then a needle is inserted
transabdominally, and about 20 mL of fluid is
aspirated.
e. Percutaneous Umbilical Blood Sampling
PUBS, or cordocentesis, is the removal of blood from the fetal umbilical cord at about 17
weeks using an amniocentesis technique. This allows analysis of blood components as
well as more rapid karyotyping than is possible when only skin cells are removed.

f. Fetal imaging
Magnetic resonance imaging (MRI) and ultrasound are diagnostic tools used to assess a
fetus for general size and structural disorders of the internal organs, spine, and limbs.
Because some genetic disorders are associated with physical appearance, both methods
may be helpful. Ultrasound is used concurrently with amniocentesis.
g. Fetoscopy
Fetoscopy is the insertion of a fiberoptic fetoscope through a small incision in the mother’s
abdomen into the uterus and membranes to visually inspect the fetus for gross
abnormalities. It can be used to confirm an ultrasound finding, to remove skin cells for
DNA analysis, or to perform surgery for a congenital disorder such as a stenosed urethra.
 h. Preimplantation Diagnosis
Preimplantation diagnosis is possible for in vitro fertilization procedures. It may be
possible in the future for a naturally fertilized ovum to be removed from the uterus by
lavage before implantation and studied for DNA analysis this same way. The ovum would
then be reinserted or not, depending on the findings and the parents’ wishes. This would
provide genetic information extremely early in a pregnancy.

Chromosome – the structure that weaves genes into strands in the nucleus of all body cells.
Genes – basic units of heredity that determine both the physical and mental characteristics of
people.
Genetics – study of how and why chromosomal disorders occur; the science of heredity.
Genome – complete set of genes present
Genotype – actual gene composition
Website: fact-sheet-9-x-linked-recessive-inheritance (genetics.edu.au)

Study Questions

• Download a research article on the topic ‘Genetic Assessment and Counselling’ from
ScienceDirect. Submit a 300-word essay reflection.

Flagg (2018). Maternal and Child Health Nursing: Care of the Childbearing and Childrearing Family.
Wolters Kluwer.