Which one of the following is an example of an autosomal recessive disorder?

Options

A. Phenylketonuria and haemophilia
B. colour blindness and haemophilia
C. Phenylketonuria and thalassemia
D. Color blindness and sickle cell anaemia

Answer

To determine which of the given options is an example of an autosomal recessive disorder, we need to understand the definitions and characteristics of autosomal recessive disorders.

### Step-by-Step Solution:

1. **Understand Autosomal Recessive Disorders**:
- Autosomal disorders are those that are linked to the autosomes (non-sex chromosomes).
- Recessive means that two copies of the recessive allele (one from each parent) are required for the disorder to manifest.

2. **Analyze the Options**:
- **Option 1: Phenylketonuria and Hemophilia**:
- Phenylketonuria (PKU) is an autosomal recessive disorder.
- Hemophilia is an X-linked recessive disorder.
- **Conclusion**: This option has one autosomal recessive disorder (PKU) and one X-linked disorder (Hemophilia).

- **Option 2: Colorblindness and Hemophilia**:
- Colorblindness is an X-linked recessive disorder.
- Hemophilia is also an X-linked recessive disorder.
- **Conclusion**: This option does not contain any autosomal recessive disorders.

- **Option 3: Phenylketonuria and Thalassemia**:
- Phenylketonuria (PKU) is an autosomal recessive disorder.
- Thalassemia is also an autosomal recessive disorder.
- **Conclusion**: Both disorders in this option are autosomal recessive.

- **Option 4: Colorblindness and Sickle Cell Anemia**:
- Colorblindness is an X-linked recessive disorder.
- Sickle Cell Anemia is an autosomal recessive disorder.
- **Conclusion**: This option has one autosomal recessive disorder (Sickle Cell Anemia) and one X-linked disorder (Colorblindness).

3. **Identify the Correct Answer**:
- The only option that contains two autosomal recessive disorders is **Option 3: Phenylketonuria and Thalassemia**.

### Final Answer:
**The correct answer is Option 3: Phenylketonuria and Thalassemia.**

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