Hereditary disease in which urine turns black on exposure due to presence of homogenetisic acid

Options

A. Ketonuria
B. Phenylketonuria
C. Hematuria
D. Alkaptonuria

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a hereditary disease characterized by urine turning black upon exposure due to the presence of a specific compound.

2. **Identifying Key Terms**: The key terms in the question are "hereditary disease," "urine turns black," and "homogenetic acid."

3. **Analyzing Options**: The options provided in the video transcript include:
- Ketonuria
- Phenylketonuria
- Hematuria
- Alkaptonuria

4. **Defining Each Condition**:
- **Ketonuria**: This condition involves the presence of ketones in urine, often associated with diabetes or starvation.
- **Phenylketonuria (PKU)**: A genetic disorder that leads to brain damage due to the inability to metabolize phenylalanine.
- **Hematuria**: This refers to the presence of blood in the urine, which can indicate various medical conditions.
- **Alkaptonuria**: This is a rare inherited disorder where the body cannot break down the amino acids phenylalanine and tyrosine, leading to the accumulation of homogentisic acid.

5. **Identifying the Correct Answer**: Among the options, Alkaptonuria is the condition that specifically mentions the presence of homogentisic acid, which is responsible for the black coloration of urine upon exposure to air.

6. **Conclusion**: The hereditary disease in which urine turns black due to the presence of homogentisic acid is called **Alkaptonuria**.