Which is not associated with Down’s syndrome?
**Core Concept**
Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. It is characterized by intellectual disability, delayed speech, and physical abnormalities such as a flat face, short neck, and an upward slanting eye. The condition is associated with various medical complications, including heart defects, leukemia, and Alzheimer's disease.
**Why the Correct Answer is Right**
The correct answer is associated with Down's syndrome because it is a characteristic feature of the condition. Individuals with Down's syndrome often have a flat face, short neck, and an upward slanting eye due to the extra copy of chromosome 21. This is because the genes on chromosome 21 control the development of the face and head.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because individuals with Down's syndrome often have a flat face, which is a characteristic feature of the condition.
**Option B:** This is incorrect because individuals with Down's syndrome are at a higher risk of developing leukemia, which is a type of blood cancer.
**Option C:** This is incorrect because individuals with Down's syndrome are at a higher risk of developing Alzheimer's disease, which is a type of dementia.
**Clinical Pearl / High-Yield Fact**
Individuals with Down's syndrome have a higher risk of developing various medical complications, including heart defects, leukemia, and Alzheimer's disease. Regular medical check-ups and early intervention can help manage these complications and improve the quality of life for individuals with Down's syndrome.
**Correct Answer: B. Leukemia.**