How is Fragile X Inherited

Summary

This video explains the inheritance of the FMR1 gene mutation linked to Fragile X syndrome, detailing how it can be passed from parents to children. It clarifies that sons inherit the Y chromosome from their fathers, while daughters of a father with a premutation become carriers. If the mother carries the mutation, each child has a 50% chance of inheriting it, with the likelihood of developing Fragile X syndrome influenced by CGG repeat counts. The importance of consulting a genetic counselor for understanding test results and family health implications is emphasized.

Takeaways

• 🧬 The fmr1 gene mutation, associated with Fragile X syndrome, is inherited through the X chromosome from either parent.
• 👶 Sons inherit their Y chromosome from their fathers, so they cannot inherit the fmr1 mutation if the mother has a normal gene.
• 👧 Daughters inherit their father's X chromosome, making them premutation carriers but rarely passing on the full mutation to their children.
• 📊 The risk of passing the fmr1 gene mutation depends on the number of CGG repeats in the mother's gene.
• 🔍 Mothers who are carriers of the gene mutation have a 50% chance of passing it to each child.
• ❗ Premutation carriers can pass the full mutation to their offspring, leading to Fragile X syndrome.
• 🧑‍⚕️ Consultation with a licensed genetic counselor is recommended for individuals with specific questions about genetic test results.
• 👨‍👩‍👧‍👦 Understanding family genetics can help in identifying at-risk family members for testing.
• 💡 Early diagnosis and intervention can positively impact health outcomes for those affected by the mutation.
• 🌐 For more information and support, individuals can contact resources like fragilex.org.

Q & A

What is the FMR1 gene mutation, and where is it located?

The FMR1 gene mutation is located on the X chromosome and can affect an individual's genetic health, particularly in relation to fragile X syndrome.

How is the FMR1 gene mutation inherited?

The inheritance of the FMR1 gene mutation can occur from either parent, except in very rare cases involving the deletion of the gene.

What is the difference between the X chromosomes in females and males?

Females have two X chromosomes, while males have one X and one Y chromosome.

If the mother has the typical FMR1 gene, what will happen to her children if the father is a premutation carrier?

The sons will not inherit the gene mutation as they receive the Y chromosome from their father. The daughters will all be premutation carriers, inheriting the father's X chromosome with the mutation.

What is the risk for daughters of a father who is a premutation carrier?

Daughters of a premutation carrier father will inherit the premutation but are unlikely to inherit the full mutation themselves, though their children may be at risk.

What happens if the mother is a carrier of the FMR1 gene mutation?

If the mother is a carrier, there is a 50% chance with each pregnancy that her child will inherit the gene mutation.

What factors influence whether a child inherits the full mutation of the FMR1 gene?

The number of CGG repeats on the FMR1 gene in the mother is the biggest known determining factor for whether the child will be a permutation carrier or inherit the full mutation.

What is fragile X syndrome?

Fragile X syndrome is a genetic condition resulting from the full mutation of the FMR1 gene, leading to various developmental issues and is the most common inherited cause of intellectual disability.

Why is it important to consult a licensed genetic counselor regarding FMR1 gene testing?

Consulting a licensed genetic counselor is important for understanding genetic test results and determining which family members should be tested, as this knowledge can affect health and inform potential interventions.

Where can individuals find more information about fragile X syndrome and treatment options?

Individuals can contact treatment resources at fragilex.org for more information regarding fragile X syndrome and available interventions.