This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic and genetic disorders, Subject name: Pediatrics
Which of the following is not observed in cri-du-chat syndrome? 
Select and explain. 
A. Hypeonia, B. Characteristic shrill cry, C. Microcephaly, D. Mental retardation
A: Hypeonia
Answer: A: Hypeonia 
Explanation: Hypotonia is seen in cri-du-chat syndrome, not hypeonia Cri-du-chat syndrome occurs due to deletion of chromosome 5p Main features: Hypotonia Characteristic shrill cry (cat-like cry) in the first few weeks of life) Microcephaly Hypeelorism Bilateral epicanthal folds High-arched palate Wide and flat nasal bridge Intellectual disability Ref: Nelson textbook of pediatrics 21st edition Pgno: 666