This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Gynae), Subject name: Gynaecology & Obstetrics
Down's syndrome is due to: 
Select and explain. 
A. 5/12 translocation, B. 18 trisomy, C. 21trisomy, D. 14/21 trisomy
C: 21trisomy
Answer: C: 21trisomy 
Explanation: Ans: c (21 trisomy)Ref: Nelson Pediatrics, 19th ed., Pg. 384Trisomy 21, Down's syndrome seen in 1/600-800 births. Please note the clinical features which are often asked Hypotonia Dysplasia of the pelvis Flat face, cardiac malformations Speckled irises Simian crease (Brushfield spots) Varying degrees of mental Short, broad hands and growth retardation Hypoplasia of middle Upward slanted palpebral phalanx of 5th finger fissures and epicanthic folds Intestinal atresia, and high arched palate