In _______ disorder, phenylalanine is accumulated and converted into phenyl pyruvic acid and other derivatives. Accumulation of these in brain results in mental retardation. These are also excreted through urine because of its poor absorption by kidney :-

Options

A. Alkaptonuria
B. Phenylketonuria
C. Sickle cell Anemia
D. Albinism

Answer

To solve the question regarding the disorder in which phenylalanine accumulates and is converted into phenylpyruvic acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Key Components**:
- The question mentions the accumulation of phenylalanine and its conversion into phenylpyruvic acid.
- It also states that this accumulation leads to mental retardation and that these compounds are excreted in urine.

2. **Understand the Disorder**:
- The disorder described is related to the metabolism of amino acids, specifically phenylalanine.
- When phenylalanine is not properly metabolized, it accumulates in the body.

3. **Link to Known Disorders**:
- The accumulation of phenylalanine is characteristic of a metabolic disorder known as Phenylketonuria (PKU).
- In PKU, the enzyme responsible for converting phenylalanine to tyrosine is deficient or absent, leading to the buildup of phenylalanine and its derivatives.

4. **Consequences of the Disorder**:
- The accumulation of these compounds in the brain can lead to neurological issues, including mental retardation.
- The excess phenylalanine and its derivatives are also poorly absorbed by the kidneys and thus excreted in urine.

5. **Final Answer**:
- The disorder in question is **Phenylketonuria (PKU)**.