2. Introduction
• It is named after John Langdon Down, the British physician
who described the syndrome in 1866.
• The condition was identified as chromosome 21 trisomy by
Jerome Lejejune in 1959.
• Down Syndrome(DS) is the leading chromosomal cause of
mental retardation
• It is the most frequently reported birth defect
(Massimini,2000).
3. • DS occurs in 1 in every 700 live births
• Increasing maternal and paternal age is a risk factor.
• It is caused by a genetic imbalance resulting in the presence of
an extra twenty-first chromosome, or trisomy 21, in all or most
of the body's cells.
4. • 95% of DS cases result from a failure of chromosome 21 to
split completely during formation of the egg or sperm
(nondisjunction).
• A gamete is a mature male or female germ cell (sperm or egg).
• When the abnormal gamete joins a normal one, the result is
three copies of chromosome 21.
• Down syndrome occurs in all human populations & analogous
effects have been found in other in species such as
chimpanzees and mice.
5. • Often D.S. associated with some impairment of cognitive
ability and physical growth.
• D.S. patient tend to have lower than average cognitive ability
and mild- moderate disabilities.
• Children with D.S. who have received family support,
enrichment therapies, tutoring have been known to graduate
from school & college.
• Very few have a severe to high degree of intellectual
disabilities.
6.
7. Clinical Features
• Common physical features of D.S. are-
• macroglosia(protruding and oversized tongue).
• Microgenia- abnormal small chin
• Flat nasal bridge
• Small oral cavity
• Short neck
• Almond shaped eyes caused by epicanthic fold of eyelids( formerly known
as Mongoloid fold)
• Joint laxity in all limbs specially in atlanto-axial joint
• The incidence of atlantoaxial instability (AAI) ranges from 15 to 20%
• (American Academy of Pediatrics).
• Shorter limbs.
• Single transverse palmar crease in one or both palms
8. • Poor muscle tone usually hypotonicity
• Larger than normal space between big toes & second toes
• They may have a broad head and very round face.
• Language skills shows difference between understanding and
expressing speech, may have delay speech.
• Adult D.S. have short stature- the average height for men is 5
feet 1 inch(157 cm), for women 4 feet 9 inches( 144 cm)
• Individuals with D.S are also at high risk of obesity as they
aged.
9. • Developmental findings include delayed development and
impaired motor control.
• Feeding problems may be evident at birth and may require
intervention.
• Musculoskeletal manifestations may include pes planus
(flatfoot).
• thoracolumbar scoliosis.
• Patellar and possibly atlantoaxial instability.
10. • Other impairments are-
• Sensory changes
• Loss of Bladder and Bowl control
• Increased loss of strength
• Decreased motor skills
• Visual impairments-cataract, nystagmus are common.
• Other health concerns are-
• Congenital Heart diseases,
• Recurrent ear infections,
• Thyroid dysfunction,
• obstructive sleep apnea.
11. Complications
• Individuals with Down syndrome have a higher risk for many
conditions.
• Approximately 40 to 66% of children with DS also have
congenital heart disease (Harris and Shea ;Marino and
Pueschel, 1996), may need to undergo major corrective
surgeries soon after birth or later in life, while minor health
problems requiring no therapy.
12. • Malignancies- hematological malignancies like leukemia are
common in individuals with D.S.
• Risk for acute lymphoblastic leukemia is at least 10 times
more common in DS and for the megakaryoblastic form
of Acute myelogenous leukemia is at least 50 times more
common in DS.
• Others are hypothyroidism, GI complications (Hirschsprung's
disease – absence of nerve cells which controls colon
movements), increased risk of development of epilepsy,
compression of spinal cord due to subluxation of atlanto- axial
joint.
13. Management
• Depends on particular manifestations of conditions-for
instance, baby with GI complications may need to undergo
major surgery to rectify the defect.
• Early childhood interventions should be involved from birth
itself so as to help, co-ordinate & plan effective strategies for
learning and development, which comprises-
• Physiotherapy-to achieve normal developmental milestones,
to improve muscle tone, prevention of orthopedic deformities.
• Speech therapy
• Occupational therapy