Chapter 2, Problem 50P

Summary Introduction

To analyze:

The given link and study the Fragile X syndrome

Introduction:

Fragile X syndrome-

It is an X- linked dominant inherited disease. The condition is characterized by trouble in learning, developmental problems, and intellectual debility. In X- linked dominant diseases, one copy of mutated allele is enough to cause the disease that is present on the X chromosome.

The trinucleotide repeats:

The DNA- Deoxyribonucleic acid is a double helix structure, comprises three lettered code known as “Codons” or “Trinucleotide repeats”. The disorders that are related to Trinucleotide repeat shows the mutation that exceeds the normal codon repeats per gene or introns, halting the normal functioning of that gene.

In Fragile X syndrome, both genders are equally affected, but the severity can be seen more in males than females. The gene that causes Fragile X syndrome is FMR $\text{1}$, located on the X chromosome. Females are less likely to be affected as there is (XX) two X chromosome, if one is mutated other can functions normally, while in case of males, there is single X chromosome that makes them prone to be affected. Females tend to show milder effects.