TRISOMY 21DOWN SYNDROME
Dr. Gupta
PL-II
Incidence
Approximately one in
1000 live births.
Genetics
 Trisomy 21 (47, +21), - 94 %, The
frequency of trisomy increases with
increasing maternal age.
 Robertsonian translocation involving
chromosome 21- Approx. 3-4 %, not
related to maternal age.
 Trisomy 21 mosaicism – 2 to 3 % cases
Clinical Features
 Head and neck
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Brachycephaly
Up-slanting palpebral fissures
Epicanthal folds
Brushfield spots
Flat nasal bridge
Folded or dysplastic ears
Open mouth
Protruding tongue
Short neck
Excessive skin at the nape of
neck
 Extremities
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Short broad hands
Short fifth finger
Incurved fifth finger
Transverse palmer crease
Space between first and second
toe
 Hyper flexibility of joints
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
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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
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50 % of Down Syndrome pts have heart disease
Atrioventricular septal defect
VSD
Secundum ASD
PDA
Tetrology of Fallot
Mitral valve prolapse
AR, MR
GI abnormalities
 5% of cases
 Duodenal atresia or stenosis, sometimes assoc
with annular pancreas in 2.5 % of cases
 Imperforate anus
 Esophageal atresia with TE fistula is less
common
 Hirschsprung’s disease
 Strong assoc with celiac disease b/w 5 – 16 % ,
5 – 16 fold increase as compared to general
population
Growth
 BW, length and HC are less in DS
 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
Eye problems
Most common disorders are
Refractory error – 35 to 76 percent
Strabismus – 25 to 57 percent
Nystagmus – 18 to 22 percent
Cataract occur in 5 % of newborns.
Frequency increases with age.
Hearing loss
 Unilateral or bilateral
 Conductive, sensorineural or mixed
 Otitis media is a frequent problem
Hematologic disorders
 The risk of leukemia is 1 to 1.5 percent.
 65% of newborn have polycythemia resulting in
hypoglycemia.
 Risk of AML and ALL is also much higher than
the general population.
 Transient leukemia – exclusively affects NB.
- It is asymptomatic with spontaneous resolution
in 2-3 months.
- Vesiculopustular skin eruptions are common
and resolve with disorder.
Endocrine disorder
 Thyroid disease – Hypothyroidism occurs
more frequently than hyperthyroidism.
 Diabetes – The risk of type 1 diabetes is
three times greater than that of the general
population.
Reproduction
 Women with DS are fertile and may
become pregnant.
 Nearly all males with DS are infertile. The
mechanism is impairment of
spermatogenesis
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.
Sleep apnea
 Obstructive sleep apnea is more common.
Skin disorder
 Palmoplantar hyperkeratosis
 Seborreic dermatitis
 Fissured tongue
 Cutis marmorata
 Geographical tongue
 Xerosis
Diagnosis
 Prenatal screening
 If no screening – It is recognized from the
characteristic phenotypic features.
 Confirmed by Karyotype.
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.
Management (cont.)
4. 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.
6. Celiac Disease – Screening should begin at 2 yrs.
Repeat screening if signs/Sx develop.
Management ( cont)
7. Hematology – CBC with differential at birth to
evaluate for polycythemia as well as WBC.
8. Atlanto-axial instability – X ray for evidence of
AAI or sub-luxation at 3 to 5 years of age.
9. 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.
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.