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*Correspondence: Dr. Preeti Bhardwaj Kothiwal Dental College Moradabad (U.P) India Phone numbers:09411405205 prety.dr@gmail.com.
Down syndrome (DS) is a genetic disorder caused by nondisjunction of 21st chromosome during gametogenesis. It is also known as trisomy 21. Most people with this syndrome have mild or moderate mental retardation, microdontia, cardiac anamolies, hypotonic muscles, and mongoloid facies.
Down syndrome, Trisomy, Non-disjunction