TRISOMY 21DOWN SYNDROME
Incidence
Approximately one in
1000 live births.
 Down syndrome is a genetic condition that causes delays in physical and
intellectual development characterized by a genetic defect in chromosome
pair 21.
 The genetic defect associated with Down syndrome is the presence of extra
material on chromosome pair 21.
 Individuals with Down syndrome have 47 chromosomes instead of the usual
46
 Down syndrome is the most frequently occurring chromosomal disorder, not
related to race, nationally, religion or socioeconomic status .
 Types and causes of Down Syndrome:
 There are 3 chromosomal patterns that result in Down Syndrome:
 1- Trisomy 21(nondisjunction) = (47, +21), - 94 %, duplication of
chromosome 21 without separation ,The frequency of trisomy increases with
increasing maternal age.
 2- Robertsonian translocation involving chromosome 21- Approx. 3-4 %, not
related to maternal age. Extra piece of chromosome tranlocated on another
chromosome 21
 3- Trisomy 21 mosaicism – 2 to 3 % cases mixture of two types of cells
some contains 47 some contains 46
 Diagnosis of Down Syndrome:

Diagnosis of Down syndrome depends on combination of clinical presentation and genetic
testing:
 1- Prenatal screening Tests estimate the
risk of baby having Down Syndrome
 2- Clinical Features
Neonatal features
 Flat facial profile
 Poor Moro reflex
 Excessive skin at the
nape of neck
 Slanted palpebral
fissures
 Hypotonia
 Hyper flexibility of
joints
 Dysplasia of pelvis
 Anomalous ears
 Dysplasia of
midphalanx of fifth
finger
 Transverse palmer
crease
Mental Retardation




Almost all DS babies have MR.
Mildly to moderately retarded .
Starts in the first year of life.
Average age of sitting(11 mon), and walking (26
mon) is twice the typical age.
 First words at 18 months.
 IQ declines through the first 10 years of age,
reaching a plateau in adolescence that continues
into adulthood.
Heart Disease
 50 % of Down Syndrome pts have heart disease
 Atrioventricular septal defect, Ventriculoseptial
defect, Tetrology of Fallot and Mitral valve
prolapse
Eye problems
Most common disorders are : Strabismus – 25 to
57 percent Nystagmus – 18 to 22 percent
Cataract occur in 5 % of newborns.
Hearing loss
 Unilateral or bilateral , Otitis media is a frequent problem
 Obstructive sleep apnea is more common.
Growth
 Reduced growth rate
 Prevalence of obesity is greater in DS
 Weight is less than expected for length in
infants with DS, and then increases
disproportion ally so that they are obese by
age 3-4 yrs
Atlantoaxial instability
 Excessive mobility of atlas (C1) and the
axis (C2), may lead to subluxation of the
cervical spine.
 Diagnosis made by lateral neck radiograph.
 Patients are advised to avoid contact
sports.
Management
1. Growth – Measurements should be plotted on the appropriate growth
chart for children with DS.
 This will help in prevention of obesity and early diagnosis of celiac
disease and hypothyroidism.
2. Cardiac disease – All newborns should be evaluated by cardiac ECHO
for CHD in consultation with pediatric cardiologist.
3. Hearing – Screening to be done in the newborn period, every 6
months until 3 yrs of age and then annually.
Eye disorders - An eye exam should be performed in the newborn period
or at least before 6 months of age to detect strabismus, nystagmus,
and cataracts.
5. Thyroid Function – Should be done in newborn period and should be
repeated at six and 12 months , and then annually.
Management (cont.)
6- Atlanto-axial instability – X ray for evidence of
AAI or sub-luxation at 3 to 5 years of age.
7- Alzheimer’s disease – Adult with a Down
Syndrome has earlier onset of symptoms. When
diagnosis is considered, thyroid disease and
possible depression should be excluded.
8- Dental Care: The teeth tend to be small,
irregularly and spaced, early dental Care is required
to ensure adequate dentition
9-Special education Training for mentally retarded
children
The Roles of physiotherapists:







1-Correct posture alignment
2- maintain normal ROM
3-Prevent long term of orthopaedic deformities
4- Use elastic bands to prevent excessive hip movements
5- Radiographic screening to determine presence of neck instability
6- promote optimal growth and development
7- Identify complications associated with down Syndrome
 In Evaluation:





Hypotonia
Delay in achieving gross motor milestones (sitting, standing and walking)
Retarded development of postural reactions due to ligamentous laxity, decreased
strength and hypotonia
Walking is painful and endurance will be decreased
Trunk posture, ligamentous laxity, hypotonia, decreased strength of the trunk lead to
development of kyphosis when the child learn to sit
 They never learn to active move their pelvis in upright position
cannot hold their head and trunk erect position, result in impaired
breathing, role of P.T help the child to learn the proper sitting.
 Atlantoaxial instability : up to 15% of children with DS result in
impingement on the spinal cord with neurological signs, careful
counselling should ensure that activities are modified.
 They are delayed in acquistation of movement control and antigravity
strength: the rate of development is slower than normal
 Persistence of primitive reflexes beyond their normal age
 Failure to achieve normal balance and walking, lack sufficent power
to maintain stability
 Hypotonia, delayed reaction, increased reaction time
 Treatment:
 1- Down syndrome children are managed by muiltidiscripancy team of
health care professionals
 2-Special education and training are given yo children with mental
retardation
 3-Repeated screening and treatment are essenital to children having visual
and hearing problems
 4- early intervention with P.T should begin shortly after birth to improve
muscle strength that essnital for achiving noraml motor development
 5- Physiotherapist should teach these children the proper way for standing
and reducing gait problems
 6- Therapist should teach these children the proper way of promotion of
postural control and balance
 7- Intervention should begin in the age of 6-8 weeks after birth in the way of
indvidual treatment and home programs are recommended
 8- Active interventions should be ended after achiving functional walking
and balance in standing(24 – 26 months)
 9- Postural reaction should be taught to children(righting, equilbrium and
protective reactions)
 10- Automatic stability and balancing skills should be achieved by these
children in static and dynamic positions
 11- Gait training to achieve proper walking skills
 12- Chest physiotherapy to improve :

Respiratory efficiency
 Increase lung expansion
 Remove Secretions
 By Postural drainage, Chest percussion, chest vibrations, Deep breathing
exercises
Mortality
Median age of death has increased from 25 yrs
in 1983 to 49 yrs in 1997, an average of 1.7 yrs
increase per year.
Most likely cause of death is CHD, Dementia,
Hypothyroidism and Leukemia.
Improved survival is because of increased
placements of infants in homes and
changes in treatment for common causes of
death.
Survival is better for males and blacks.
Counseling
 May begin when a prenatal diagnosis is made.
 Discuss the wide range of variability in
manifestation and prognosis.
 Medical and educational treatments and
interventions should be discussed.
 Initial referrals for early intervention, informative
publications, parent groups, and advocacy
groups.