Down’s syndrome an update

everything regarding DOWN'S SYNDROME is given with updates.

1. 1 in 650 to 700. Nomenclature This condition derives its name from Dr. Langdon Down ,who first described it in the clinical lecture reports of the London hospital in 1866.

2. Abnormality Frequency (%) Trisomy 21. (nondisjunction of chr.-21 in maternal meiosis – 1). 95 Robertsonian translocation –D/G-(21q/21q , 22q/21q ) 4 Mosaicism (Often less severely affected than those with full syndrome.) 1

3. Cause Recurrence risks Trisomy 21 1/200 to 1/100 Translocation Male: 1-3% Female: 10-15% Translocation between 21q & 21q 100%

4. Newborn period: Hypotonia , sleepy excess nuchal skin . Craniofacial: Brachycephaly ; epicanthic folds & brush-field spots on eye ; upward sloping palpebral fissures ; protruding tongue ; small ears ; flat nasal bridge . Limbs: Single palmar crease ( “simian crease” ) , small middle phalanx of 5 th finger , wide gap between 1 st & 2 nd toes . Cardiac: Atrial & ventricular septal defect ; common atrioventricular canal ; patent ductus arteriosus . Others: Anal atresia , duodenal atresia , Hirsch-prung disease. Short stature , strabismus . Average I.Q. of young adults is around 40 to 45(RANGE → 20-50) . Social skills well-developed , most of the children are happy & very affectionate . May be associated with ALL & AML(M7) . Antibody against thyroid may develop- Autoimmune Thyroiditis.

5. They are susceptible to infection & often have congenital heart disease ( in about 50% of all cases ). So , they usually die young . Generally they have a lifetime of about 40 – 50 years , except in severe cases .

6. High resolution USG. Chorionic villus analysis . Cultured amniotic cells . FISH technique . Prenatal screening programmes have been introduced based on the so called “triple” or “quadruple” tests of maternal serum at 16 weeks’ gestation .

7. Diagnosis by FISH technique

8. Epicanthic fold Flat nasal bridge Protruding tongue Karyotype: Trisomy 21 Robertsonian translocation Mosaicism Simian crease Brushfield spots Epicanthic fold Short ear Protruding tongue Large gap between 1 st & 2 nd toes

9. Questions? Questions? Questions? Questions??