This document outlines the learning objectives regarding Down syndrome, covering its definition, types, aetiology, epidemiology, clinical features, and management of the condition. Down syndrome is a genetic disorder caused by the presence of an extra chromosome 21, with three main types: full trisomy 21, mosaicism, and translocation. It presents with various clinical features and complications, necessitating a multidisciplinary approach for supportive care and therapeutic interventions.

1. DOWN SYNDROME

2. Learning Objectives
By the end of this session, a student is
expected to learn the following;
–Definition and types of Down syndrome
–Explain aetiology/risk factors Down syndrome
–Outline epidemiology of Down syndrome
–Explain clinical features of Down syndrome
–Establish diagnosis/ provisional and
differential diagnosis of Down syndrome

3. Learning Objectives cont...
–Provide pre-referral treatment of Down
syndrome
–Provide appropriate supportive care for Down
syndrome
–Provide counselling and follow-up services of
Down syndrome

4. Definition of Down syndrome
Is a genetic disorder caused by the presence
of all or part of a third copy of chromosome
21
OR
Is a genetic disorder caused when abnormal
cell division results in an extra full or partial
copy of chromosome 21

5. Types of Down Syndrome
1. Full Trisomy 21 Down syndrome
Trisomy 21 means there’s an extra copy of
chromosome 21 in every cell making a total
number of 47 instead of 46. This is the
most common form of Down syndrome.
Accounts 94% of all Down Syndrome cases
Can not be inherited and female cases are
fertile

6. Types of Down Syndrome cont…
2. Mosaicism Down syndrome
Mosaicism occurs when a child is born with
an extra chromosome in some but not all of
their cells. People with mosaic Down
syndrome tend to have fewer symptoms
than those with trisomy 21.
Accounts 2.4% of all Down Syndrome
cases
Can not be inherited, male cases are fertile

7. Types of Down Syndrome cont…
3. Translocation Down syndrome
In this type of Down syndrome, children
have only an extra part of chromosome 21.
There are 46 total chromosomes.
However, one of them has an extra
piece of chromosome 21 attached.
Accounts 3.3% of all Down Syndrome
cases
Can be inherited, cases are infertile

8. Epidemiology of Down
Syndrome
• It is the cause of 8% of all congenital disorders. Each year,
approximately 6000 children are born with down syndrome.
• Down syndrome accounts for about 33.3% of all moderate
and severe mental handicaps in school - aged children.
• Globally, as of 2010, Down syndrome results in about
17,000 deaths. The prevalence of Down syndrome
worldwide has increased because of increases in life span
in the last few decades

9. Aetiology of Down Syndrome
 Down syndrome is caused by three cytogenetic
variants namely;
1. Results from non disjunction during meiosis in
one of the parents - full trisomy 21 type.
2. Chromosomal translocation – part of
chromosome 21 attach to another chromosome.
3. Mosaicism – Most cases result from a trisomic
zygotic with mitotic loss of one chromosome.

10. Risk Factors of Down Syndrome
 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

11. Risk Factors of Down Syndrome cont…
 95% is due to maternal disjunction and 5%
from paternal disjunction
 Being carriers of the genetic
translocation for Down syndrome
 Having had one child with Down
syndrome

12. Pathogenesis of Down
Syndrome
• All cells in the body contain genes that are
grouped along chromosomes in the cell nucleus.
• There are normally 46 chromosomes in each cell -
23 inherited from the mother and 23 from the
father
• When some or all of a person’s cells have an
extra full or partial copy of chromosome 21,
Down syndrome occurs
– This extra chromosome causes problems as
the brain and physical features develop

13. Clinical Features of Down
Syndrome
– Flat occiput and a Flattened facial
appearance
– Small brachycephalic head
– Epicanthal folds
– Short neck
– Protruding tongue
– Upward slanting eye lids (palpebral fissures)
– Unusually shaped or small ears
– Poor muscle tone (Neuromuscular Hypotonia)
– Short height

14. Clinical Features of Down
Syndrome cont…
– Broad, short hands with a single crease in the
palm
– Relatively short fingers and small hands and
feet
– Joint hyper flexibility and hyper extensibility
– Tiny white spots on the colored part (iris) of
the eye called Brush field's spots
– Deviated foot toes (wide space between first
and second toes) – sandal gap
– Small nose and Flat nasal bridge
– Protruding tongue

15. Clinical Features of Down
Syndrome cont…
• Children with Down syndrome often reach
developmental milestones a little later than their
peers
– For example, there may be a delay in learning to
talk. A child may need speech therapy to help
them gain expressive language
• Fine motor skills may also be delayed. They can take
time to develop after the child acquires gross motor
skills
– On average, a child with Down syndrome will: sit
at 11 months, crawl at 17 months and walk at 26
months

16. Clinical Features of Down Syndrome
cont…
• There may also be problems with
attention, a tendency to make poor
judgments, and impulsive behavior.
• Have mild to moderate cognitive
impairment
• Language is delayed
• Short and long-term memory is affected

17. Complications of Down
Syndrome
– Heart defects (50%) e.g. atrioventricular septal
defect or ventricular septal defect, tetralogy of
Fallot and patent ductus arteriosus
– Gastrointestinal (GI) defects; such as
Duodenal atresia, Gastroesophageal reflux
disease, pyrolic stenosis, Hirschsprung’s
disease, Meckel’s diverticulum Anorectal
malformations - Imperforate anus or celiac
disease
– Sleep apnea; greater risk of obstructive sleep
apnea follows soft tissue and skeletal changes
that lead to the obstruction of

18. Complications of Down Syndrome cont…
– Immune disorders; abnormalities in immune
systems, poses increased risk of developing
autoimmune disorders, some forms of cancer
and infectious diseases, such as pneumonia
– Neoplasms; acute lymphoblastic leukemia and
the acute myeloid leukemia (acute
megakaryoblastic leukemia), testicular germ
cell cancer
– Dementia; signs and symptoms may begin
around age 50. Having Down syndrome also
increases the risk of developing Alzheimer's
disease

19. Complications of Down
Syndrome cont…
– Endocrine disease - congenital
hypothyroidism, Graves' disease/autoimmune
hypothyroidism, Type 1 diabetes mellitus
– Dental problems - gingivitis as well as early,
severe periodontal disease, necrotizing
ulcerative gingivitis, and early tooth loss
– Infertility – especially males
– Obesity

20. Complications of Down
Syndrome cont…
– Spinal problems. misalignment of the top two
vertebrae in the neck (atlantoaxial instability)
increases likelihood of serious injury to the
spinal cord from overextension of the neck
– Neurological – Epileptic seizures, Anxiety,
depression, hearing and vision problems and
autism
– Respiratory infections - Pneumonia, Ear
infections

21. Differential Diagnosis of Down
Syndrome
• Trisomy 13 (Patau syndrome)
• Trisomy 18 (Edwards syndrome)
• Crouzon syndrome
• CHARGE syndrome
• Robertsonian trisomy 21
• Zellweger syndrome

22. Investigations of Down Syndrome
• Diagnostic tests for Down syndrome
– Perinatal screening – alpha fetoprotein and genetic
testing/karyotyping
• Diagnostic tests for associated defects
– ECHO and ECG
– Abdominal pelvic ultrasound; Cranial USS
– Chest X – ray; Brain CT scan and/or MRI; EEG
• Routine tests
– Full blood picture; CRP/ESR

23. Treatment Plans of Down
Syndrome
• Supportive;
– a wide range of support and educational
programs that help both children with the Down
syndrome and their families exist.
– Collaboration from different disciplines is
necessary as there’s no one-size-fits-all
approach to treatment
– A team of providers include pediatrician, ENT
specialist, cardiologist, social workers and
others depending on complications present.
e.g. child may need help in crawling and
walking to talking and learning how to be social

24. Treatment plans of Down
syndrome cont…
• Physical occupational, and speech therapists are
all important
• Children with specific learning and development
difficulties may be eligible for educational support,
either in a mainstream or specialized school
• In recent years, the tendency has been to attend
mainstream schools, often with additional support
to help them integrate and progress
• Some children will make use of an Individualized
Education Program (IEP), which various
specialists will support

25. Counselling
• About the disease and its associated
conditions
• Adequate feeding
• Attend paediatric clinics for early detection
of syndrome related complication
• Genetic counseling

26. Follow up
• Developmental milestone/skills
• Anthropometrics
• Systemic screening/testing

27. Prognosis of Down
Syndrome
• Variable depending on the associated
complications
– ~75% of conception with trisomy 21 die in utero
– ~25-30% die in before 1st birthday; mainly from
bronchopneumonia and CHDs
– Some grow and live almost entirely on their own,
while others will need more help taking care of
themselves
– early right care makes a big difference in helping
such clients live a full and meaningful life

28. Prevention of Down Syndrome
• Primary:
– not preventable directly; however may reduce a risk
factor of giving birth at advanced age, genetic
counseling of reducing number of pregnancies in a
family that already have a child with Down syndrome
or a family history of the same
• Secondary: Early diagnosis (surveillance,
screening and testing) and multidisciplinary
approach of Down syndrome
• Tertiary: Management of evolving diseases and
complications of Down syndrome

29. Key Points
• Down syndrome is a genetic disorder. It
includes certain birth defects, learning
problems, and facial features. A child with
Down syndrome also may have heart defects
and problems with vision and hearing.
• A mother’s age at her child’s birth is the only
factor linked to the risk of having a baby with
Down syndrome. This risk increases with each
year of age, especially after age 35.

30. Key Points cont…
• Down syndrome can often be diagnosed before birth.
After birth, your baby may be diagnosed with a
physical exam. The healthcare provider may also take
a blood sample
• There is no cure for Down syndrome, but treatment is
available to help your child
• A child may need physical, occupational, and speech
therapy to help with his or her development. Many
children are helped with early intervention and special
education

31. Evaluation
1. A 4-year-old child presents with history of
delayed developmental skills and she was
born to a 55 year mom. The history of
colostomy at the 4th
day of extra uterine life
was remarkable. On examination: had flat
occiput with protruded tongue. Describe
the management of this child based on
diagnosis and definition, differential
diagnosis, investigations, treatment,
and follow – up.

32. References
• Tanzania standard treatment guidelines and essential
medicines list for children and adolescents - First Edition
October 2017
•
• Sathy (2005) Practical Paediatrics
2nd
Ed,PublisherElsevier,a division of Elsevier India private
LTD-New Delhi-INDIA
• Coovadia H.M,(1999) Paediatric & Child Health a Manual
for Health Professionals in the third World.
• Nelson Textbook of Paediatrics – 19th
Edition