Rett Syndrome
If one child has Rett Syndrome, can my next child have it too?
Most Rett Syndrome cases arise from a new, non-inherited MECP2 gene change, so the chance of a future child being affected is usually low (around 1% or less) — though a small number of families carry a higher risk, which genetic counselling and parental testing can clarify. A clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre under qualified clinician care.
When you've already walked the Rett journey with one child, it's natural to wonder what a future pregnancy might hold — here is the gentle, honest picture.
In short
In the great majority of families, Rett Syndrome arises from a brand-new (de novo) change in the MECP2 gene that was not inherited from either parent — so the chance of it happening again in a future child is usually low, around 1% or less. A smaller number of families carry a higher recurrence risk, which is exactly why genetic counselling and testing are so valuable before planning your next pregnancy. Only a clinical genetics team, looking at your child's specific gene result, can give you a figure that truly fits your family.Understanding the genetics, gently
Rett Syndrome is most often caused by a change in a single gene called MECP2, found on the X chromosome. A few important things help make sense of recurrence:- Most cases are de novo. The genetic change happened spontaneously, for the first time, in your child — it was not passed down. When this is confirmed, the chance of a sibling being affected is small.
- A small chance of "germline mosaicism". Occasionally a parent carries the change only in some of their egg or sperm cells without being affected themselves. This is why the recurrence risk is quoted as low rather than zero, and why testing matters.
- Rarely, a mother is a carrier. In a small number of families a mother carries an MECP2 change without symptoms (because of how the X chromosome works). Here the recurrence chance is meaningfully higher — and knowable in advance through testing.
This is why no honest answer can be a single number for everyone. The path forward is clear and reassuring: find out which situation applies to your family.
Your practical next steps
- Ask for genetic counselling — ideally before a next pregnancy. A genetic counsellor reviews your child's confirmed MECP2 result and your family history.
- Parental testing can clarify whether a parent carries the change, turning uncertainty into a clear, personal risk figure.
- Prenatal and reproductive options (such as prenatal testing) can be discussed once your family's specific risk is understood.
Knowledge here is empowering — it replaces worry with a plan.
The Pinnacle way
A clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care — never from an app or online form, and recurrence risk itself is confirmed through a clinical genetics service. While genetic questions are answered by your genetics team, Pinnacle walks beside your child's development every day — explore our [therapy and developmental support](/) for children with Rett Syndrome, understand your child's profile through the clinician-administered AbilityScore®, and see how occupational therapy supports daily skills and communication.Trusted sources
WHO ICD-11 classifies Rett Syndrome and its genetic basis; the American Academy of Pediatrics (HealthyChildren.org) describes the typically de novo, non-inherited nature of most cases; NICE guidance supports referral to clinical genetics for counselling and recurrence-risk assessment.Next step — For your child's day-to-day development, [book a developmental assessment with a Pinnacle clinician](/) — and ask your paediatrician for a referral to a clinical genetics service to confirm your family's specific recurrence risk.
This is general information, not a diagnosis — a clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre under qualified clinician care.
What to watch
Before planning a future pregnancy, watch for whether your child's MECP2 gene result has been confirmed and whether parental genetic testing has been done — these determine your family's true recurrence risk and should prompt referral to a clinical genetics service.
Try this at home
Keep a copy of your child's genetic test report; it is the single most useful thing to bring to a genetic counselling appointment when planning your next pregnancy.
Trusted sources
Developed by SETU Consortium · Pinnacle Blooms Network · Last reviewed 2026-06-10
This is general information, not a diagnosis. A clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care.
Frequently asked
Is Rett Syndrome usually inherited?
No — in most children Rett Syndrome is caused by a brand-new (de novo) change in the MECP2 gene that was not passed down from either parent. This is why the chance of a sibling being affected is usually low.
What is the typical recurrence risk for a future child?
When the gene change is confirmed to be de novo, the recurrence risk is generally quoted as low — around 1% or less — to allow for the rare possibility of germline mosaicism. A clinical genetics team gives your family its exact figure.
How can I find out my family's exact risk?
Ask your paediatrician for a referral to a clinical genetics service. Genetic counselling, alongside your child's confirmed MECP2 result and sometimes parental testing, gives a personalised recurrence risk before a future pregnancy.
Can a parent carry the gene without symptoms?
Rarely, yes — a mother may carry an MECP2 change without symptoms because of how the X chromosome works. This raises recurrence risk and is exactly what genetic testing is designed to detect.