Downs syndrome [TRISOMY 21]is the most common autosomal chromosome disorder..it is caused by nondysjunction [ failure to seperate chromosome at meosis- a form of cell division]during oogenesis.This syndrome is common witth increasing maternal age.around5% occur due to traslocation[ tranfer of chromosome material from one chromosome to other,chr14 and 21another 1% is due to mosaicism [ amixture of trisomy 21and karyotypically normal cells]'
CLINICAL FEATURE :brachycephly[small anteroposterior diameter],upslanting of eyes,epicanthic folds, protruded tongue,single plantar crease,incurved fingers[clinodactly] ,wide gap between 1st and 2nd toes,hypotonia, mental retardation
other feature include
@cardiovascular malformationsin 40% -atrioventricular septal defects
@duodenal atresia[non patency of duodenum],hirschsprungs disease
@acute lymphoblastic leukemia[ALL], acute myeloblastic leukemia[AML] nad trasient abnormal myelopoiesis
@hypothyroidism
@alzheimiers disese in majority by 40 years
downs syndrome can be diagnosed antenatally with maternal screening using, alpha foeo protein[14-16 wks],UE3,HCGand PAPP-A,AMNIOTIC FLUID STUDIES,CHORIONIC VILLOUS SAMPLING,ULTRA SOUND AT 11-20 WKS ARE ALSO USEFUL.
MESSAGE FOR PARENTS
* it is a life long problem
*many downs children attain high level of functioning and independence
*address medical and developmental problems 