Source: Indian Express
Why in News?
Every year on 22nd July, World Fragile X Awareness Day is observed to raise awareness about the rare genetic disorder Fragile X, also known as Martin-Bell syndrome.
What is Fragile X or Martin-Bell Syndrome?
About:
- Fragile X syndrome (FXS) is an inherited genetic disease passed down from parents to children that causes intellectual and developmental disabilities.
- FXS is the most common hereditary cause of mental disability in boys. It affects 1 in 4,000 boys.
- It’s less common in girls, affecting about 1 in every 8,000. Boys usually have more severe symptoms than girls.
- People with FXS usually experience a range of developmental and learning problems.
- The disease is a chronic or lifelong condition. Only some people with FXS are able to live independently.
Causes:
FXS is caused by a defect in the FMR1 gene located on the X chromosome.
The FMR1 (Fragile X Mental Retardation 1 gene) gene is located on the X chromosome in humans. It is responsible for producing a protein called FMRP (Fragile X Mental Retardation Protein), which plays a crucial role in normal brain development and function.
Risks:
- Women who are carriers are at an increased risk for premature menopause, or menopause that starts before the age of 40.
- Men who are carriers are at increased risk for a condition known as Fragile X Tremor Ataxia Syndrome (FXTAS).
- The disorder results in progressive cerebellar ataxia, action tremor, Parkinsonism and cognitive decline.
- It also can lead to difficulty with balance and walking. Male carriers may also be at an increased risk for Dementia.
Linked with Inheritance:
Women who carry Fragile X have a 50% chance of passing the mutated gene to each of her children. If she passes the affected gene, her children will either be carriers, or they will have Fragile X syndrome.
Men who carry Fragile X will pass the premutation to all their daughters but none of their sons. These daughters are carriers, but they do not have Fragile X syndrome.
