This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics And Genetic Disorders, Subject name: Pediatrics
All the following are features of Down syndrome except: 
Select and explain. 
A. Brushfield's spots in iris, B. Simian crease, C. Mental retardation, D. Hypertonia
D: Hypertonia
Answer: D: Hypertonia 
Explanation: d. Hypertonia(Ref: Nelson's 20/e p 610-615, Ghai 8/e p 637-639)Hypotonia is a feature of Down syndrome and not hypertoniaImportant clinical features of Down SyndromeI C a PROBLEM SomewhereIncurved 5th finger (clinodactylyQ/Intellectual disabilityCongenital heart diseaseQAcute Leukemia/Alzheimer's diseaseQ/Atlantoaxial instabilityQProtruding tongueRound faceOcciput flat/Open, wide fontanelleQBrushfield spots in irisQ/BrachycephalyLow (depressed) nasal bridgeEpicanthic foldQ/Ears low-set & dysplasticMonogoloid slantQ/Mental retardationSandle gapQ/Simian palmar creaseQ