100% recurrence of disease in Down’s syndrome
**Core Concept**
Down's syndrome is a genetic disorder caused by an extra copy of chromosome 21, leading to various physical and cognitive abnormalities. Individuals with Down's syndrome are at an increased risk of developing certain medical conditions, including leukemia and gastrointestinal atresias.
**Why the Correct Answer is Right**
The condition associated with 100% recurrence in Down's syndrome is leukemia, specifically acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Studies have shown that children with Down's syndrome have a significantly higher incidence of leukemia, with some reports indicating a 100% recurrence rate. The exact mechanism is not fully understood, but it is thought to be related to the extra copy of chromosome 21, which may lead to overexpression of certain genes involved in cell growth and proliferation.
**Why Each Wrong Option is Incorrect**
* **Option A:** While gastrointestinal atresias are a common complication in Down's syndrome, they do not have a 100% recurrence rate.
* **Option B:** Congenital heart defects are also prevalent in Down's syndrome, but they do not have a 100% recurrence rate.
* **Option C:** Alzheimer's disease is a concern in older adults with Down's syndrome, but it is not specifically associated with a 100% recurrence rate.
**Clinical Pearl / High-Yield Fact**
Down's syndrome individuals are at a higher risk of developing leukemia due to the extra copy of chromosome 21, which may lead to overexpression of certain genes involved in cell growth and proliferation.
**Correct Answer: D. Leukemia**