Failure of closure of posterior neupore causes?
**Core Concept**
The posterior neuropore is a critical structure in the early development of the central nervous system (CNS). Its failure to close can lead to the formation of a neural tube defect, which affects brain development and function.
**Why the Correct Answer is Right**
The posterior neuropore is a small opening at the end of the neural tube that should close by the 28th day of gestation. Failure of closure results in a defect in the neural tube, leading to conditions such as spina bifida or anencephaly. This is due to the abnormal development of the neural crest cells and the failure of the neural tube to undergo proper closure.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the failure of closure of the posterior neuropore.
**Option B:** While anencephaly is a neural tube defect, it is not the specific result of failure to close the posterior neuropore. Anencephaly typically occurs when the anterior neuropore fails to close.
**Option C:** This option is incorrect because spina bifida is a neural tube defect, but it is more commonly associated with failure of closure of the anterior neuropore.
**Clinical Pearl / High-Yield Fact**
Neural tube defects can occur due to genetic or environmental factors, including maternal diabetes, folic acid deficiency, and exposure to certain toxins.
**Correct Answer: C. Spina bifida**