Down syndrome, also known as trisomy 21, is a genetic disorder in which a person has extra
chromosome. Chromosomes are small “packages” of genes in the body. They determine how a baby’s
body forms and functions as it grows during pregnancy and after birth. Typically, a baby is born with 46
chromosomes. Babies with Down syndrome have an extra copy of one of these chromosomes,
chromosome 21. A medical term for having an extra copy of a chromosome is ‘trisomy.’ Therefore, Down
syndrome is also referred to as Trisomy 21.
1.4.1 DESCRIPTION
Trisomy 21, also known as Down syndrome, is a genetic disorder caused by the presence of an
extra copy of chromosome 21 in a person's cells. Typically, individuals have 46 chromosomes in each cell,
with 23 inherited from each parent. However, in individuals with trisomy 21, there is an additional copy of
chromosome 21, resulting in a total of 47 chromosomes. This extra genetic material disrupts normal
development and leads to the characteristic physical and intellectual features associated with Down
syndrome.
1.4.2 TYPES
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Trisomy 21
 (nondisjunction) accounts for 95% of known cases of Down syndrome. This type of Down
syndrome results in an embryo with three copies of chromosome 21 instead of two and
happens when a pair of 21st chromosomes in either the sperm or the egg fails to
separate before or during conception. This causes the extra chromosome to be replicated
in every cell of the body.
Translocation Down Syndrome
 accounts for 4% of all cases of Down syndrome. In this occurrence, part of chromosome
21 breaks off during cell division and attaches to another chromosome – typically
chromosome 14. The total number of chromosomes remains at 26, but the extra part of
21 causes characteristics of Down syndrome to appear.
Mosaic Down Syndrome
 occurs when nondisjunction of chromosome 21 takes place in only one of the initial cell
divisions instead of all. This causes a mixture of two types of cells, some containing 46
chromosomes while others contain 47. Mosaicism accounts for only 1% of all cases of
Down syndrome and research has indicated that individuals with mosaic Down syndrome
may have fewer characteristics than those with the other types present.
1.4.3 ETIOLOGY AND RISK FACTORS
Etiology
Trisomy 21 is caused by the presence of an extra copy of chromosome 21 in the cells. This extra genetic
material is due to a nondisjunction event during cell division, either in the egg or sperm cell.
Disease Process and Pathophysiology
During Fertilization, an egg containing two copies of chromosome 21 is fertilized by a sperm containing
one copy, resulting in the formation of a zygote with three copies of chromosome 21. The trisomic zygote
continues to divide and develop into an embryo with three copies of chromosome 21 in every cell. The
presence of the extra chromosome 21 disrupts normal embryonic development, leading to structural and
functional abnormalities.
Risk factors
Advancing maternal age. A woman's chances of giving birth to a child with Down syndrome increase
with age because older eggs have a greater risk of improper chromosome division. A woman's risk of
conceiving a child with Down syndrome increases after 35 years of age. However, most children with
Down syndrome are born to women under age 35 because younger women have far more babies.
Being carriers of the genetic translocation for Down syndrome. Both men and women can pass the
genetic translocation for Down syndrome on to their children.
Having had one child with Down syndrome. Parents who have one child with Down syndrome and
parents who have a translocation themselves are at an increased risk of having another child with Down
syndrome. A genetic counselor can help parents assess the risk of having a second child with Down
syndrome.
1.4.4 ASSESSMENT FINDINGS (CLINICAL MANIFESTATIONS)
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Flat occiput and a flattened facial appearance.
Hypotonia
Small brachycephalic head.
Flat nasal bridge.
Upward-slanting palpebral fissures.
Brushfield spots.
Protruding tongue.
Small and dysplastic ears.
Generous nuchal skin.
Intellectual disability, ranging from mild to moderate.
Developmental delays in motor skills, speech, and language.
Congenital heart defects, which may require surgical intervention.
Gastrointestinal abnormalities, such as esophageal atresia or Hirschsprung's disease.
Hearing and vision problems.
Increased risk of certain medical conditions, including thyroid disorders, leukemia, and earlyonset Alzheimer's disease.
1.4.5 DISEASE PROCESS AND PATHOPHYSIOLOGY
With Down Syndrome or trisomy 21, a process called nondisjunction accounts for about 95% of
cases. Non-disjunction means the chromosomes don’t split apart. If the chromosomes in this first step
don’t split apart, then one cell ends up with both chromosomes and the other gets none. Then the final
result is 2 cells with an extra chromosome, and two cells missing a chromosome. Now, if a sperm cell
combines with any of these that have a duplicate of chromosome, then the combined cell will have one
extra copy of chromosome 21, in other words, “three chromosome 21s”, or trisomy 21. Having an extra
chromosome 21 is one of the most common chromosomal disorders and not surprisingly it has an effect
on almost every organ system in the body. It is typically associated with a delay in cognitive ability,
physical growth and particular set of body and facial characteristics.
1.4.6 AT LEAST FOUR (4) RELEVANT NURSING DIAGNOSES RANKED ACCORDING TO PRIORITY
1. Impaired Verbal Communication: difficulty forming words and sentences r/t Speech and
Language Delay.
2. Impaired Social Interaction: difficulty initiating and maintaining social relationships r/t Cognitive
and Developmental delays.
3. Risk for aspiration r/t Oral Motor Dysfunction.
4. Risk for sudden infant death r/t congenital heart defects
1. Predisposing Factors:
 Advanced maternal age: Women aged 35 and older have a higher risk of conceiving a
child with Down syndrome. This is because as women age, the chances of errors in
chromosome division during egg formation increase.
 Parental carrier of chromosomal translocation: In rare cases, one of the parents may
carry a balanced translocation involving chromosome 21. This increases the risk of
passing on an extra copy of chromosome 21 to the offspring.
 Previous child with Down syndrome: Parents who have had a child with Down syndrome
have a slightly increased risk of having another child with the condition.
 Maternal exposure to certain environmental factors: Prenatal exposure to factors such
as certain chemicals, radiation, or infections may slightly increase the risk of Down
syndrome, though the exact mechanisms are not fully understood.
2. Precipitating Factors:
 Errors during cell division: During the formation of reproductive cells (eggs or sperm),
errors can occur in chromosome division, leading to an extra chromosome 21 in the
embryo.
 Maternal lifestyle factors: Maternal lifestyle choices such as smoking, excessive alcohol
consumption, or poor nutrition during pregnancy can increase the risk of chromosomal
abnormalities, including Trisomy 21.
 Maternal medical conditions: Certain maternal medical conditions, such as diabetes,
obesity, or autoimmune disorders, may be associated with an increased risk of having a
baby with Down syndrome.
 Exposure to certain medications: Some medications taken during pregnancy may
increase the risk of chromosomal abnormalities in the fetus.
 Environmental factors: While the role of environmental factors is not fully understood,
exposure to certain environmental toxins or pollutants may contribute to the
development of Down syndrome in some cases.
Nursing Management:
Provide adequate nutrition to the patient: Individuals with Down syndrome often have specific
nutritional needs or may face challenges in feeding due to oral-motor difficulties. Proper nutrition supports
overall health, growth, and development, helping to mitigate potential complications associated with
malnutrition.
Advice the parents to regularly visit their doctor: Regular medical check-ups allow for early detection
and management of any emerging health issues. Prompt intervention can prevent complications and
improve the overall health outcomes for individuals with Down syndrome.
Assess the parents’ understanding towards Down Syndrome: Understanding the condition helps
parents effectively support their child's needs, navigate healthcare systems, and access appropriate
resources and therapies. It also aids in fostering a positive family environment conducive to the child's
well-being.
Provide emotional support and motivation to the family: A diagnosis of Down syndrome can be
challenging for families, emotionally and psychologically. Offering emotional support and motivation helps
families cope with the challenges, build resilience, and maintain a positive outlook, which in turn
contributes to the overall well-being of the individual with Down syndrome.
Medical Management:
Regular health monitoring: Down syndrome is associated with various medical conditions such as
congenital heart defects, thyroid disorders, and respiratory issues. Regular health monitoring enables
early detection and intervention, which can prevent complications and improve outcomes.
Management of congenital heart defects: Congenital heart defects are common in individuals with
Down syndrome. Effective management involves timely diagnosis, specialized care, and potentially
surgical intervention to address structural abnormalities and ensure optimal cardiac function.
Respiratory support: Individuals with Down syndrome may have respiratory problems, such as
obstructive sleep apnea or respiratory infections. Respiratory support, including interventions such as
oxygen therapy or mechanical ventilation, when necessary, helps maintain adequate oxygenation and
respiratory function.
Medication management: Individuals with Down syndrome may require medications for various reasons,
such as managing thyroid dysfunction, cardiac conditions, or other associated health issues. Proper
medication management ensures appropriate dosing, monitoring for side effects, and adherence to
treatment regimens.
Pharmacologic Management:
Administration of Thyroid hormone: Hypothyroidism is common in individuals with Down syndrome.
Administering thyroid hormone replacement therapy helps normalize thyroid function, promoting overall
health and preventing associated complications such as growth delays and cognitive impairment.
Digitalis and Diuretics: These medications are commonly used in the management of congenital heart
defects, which are prevalent in individuals with Down syndrome. Digitalis helps improve cardiac function,
while diuretics help manage fluid retention, contributing to better cardiovascular health.
Vaccines: Individuals with Down syndrome may be more susceptible to certain infections due to immune
system differences. Vaccination helps prevent serious infectious diseases and their complications,
reducing the risk of illness and improving overall health outcomes.
Surgical Management:
There is no specific surgical treatment for Down syndrome: Down syndrome itself does not require
surgical intervention. However, if there are associated health problems such as congenital heart defects
or gastrointestinal issues, surgical treatment may be necessary. Surgical interventions aim to correct
anatomical abnormalities or alleviate symptoms, improving the quality of life for individuals with Down
syndrome.