Extra 18th autosomal chromosomes results in

Options

A. Edward's syndrome
B. Patau's syndrome
C. Down's syndrome
D. None of the above

Answer

To solve the question regarding the result of having an extra 18th autosomal chromosome, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Autosomes**:
- Autosomes are the chromosomes that are not involved in determining the sex of an individual. Humans have 22 pairs of autosomes and 1 pair of sex chromosomes.

**Hint**: Remember that autosomes are the non-sex chromosomes.

2. **Identify the Condition**:
- The question specifies an "extra 18th autosomal chromosome." This condition is known as "trisomy 18."

**Hint**: Trisomy means having three copies of a chromosome instead of the usual two.

3. **Name the Syndrome**:
- Trisomy 18 is also referred to as "Edwards syndrome." It is a genetic disorder caused by the presence of an extra 18th chromosome.

**Hint**: Look for the specific name associated with trisomy 18.

4. **Symptoms and Prognosis**:
- Individuals with Edwards syndrome often face severe developmental issues. Many do not survive past the fetal stage, and those who are born may have significant health problems and typically have a short life expectancy.

**Hint**: Consider the implications of having an extra chromosome on development and health.

5. **Eliminate Other Options**:
- Patau syndrome is associated with trisomy 13, and Down syndrome is associated with trisomy 21. Therefore, these options do not relate to the extra 18th chromosome.

**Hint**: Cross-reference the chromosome numbers with the syndromes to confirm.

### Conclusion:
The correct answer to the question "Extra 18th autosomal chromosomes results in" is **Edwards syndrome**.