{"h1":"If one child has Rett Syndrome, can my next child have it too?","faq":[{"a":"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.","q":"Is Rett Syndrome usually inherited?"},{"a":"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.","q":"What is the typical recurrence risk for a future child?"},{"a":"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.","q":"How can I find out my family's exact risk?"},{"a":"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.","q":"Can a parent carry the gene without symptoms?"}],"lang":"en","slug":"if-one-child-has-rett-syndrome-can-my-next-child-have-it-too","title":"Rett Syndrome recurrence risk in siblings","entity":{"key":"rett","kind":"condition","name":"Rett Syndrome","slug":null},"lenses":[{"kind":"stakeholder","label":"Parent","value":"parent"},{"kind":"domain","label":"Adaptive","value":"adaptive"},{"kind":"intent","label":"Support","value":"support"},{"kind":"lifecycle","label":"Plan","value":"plan"},{"kind":"route","label":"Special-Education","value":"special-education"},{"kind":"empowerment","label":"Early Clarity","value":"early_clarity"}],"parent":{"key":"conditions","label":"Conditions"},"related":[{"lang":"en","slug":"can-rett-syndrome-be-prevented","title":"Can Rett Syndrome Be Prevented?"},{"lang":"en","slug":"what-causes-rett-syndrome-in-young-children","title":"What Causes Rett Syndrome in Young Children?"},{"lang":"en","slug":"does-rett-syndrome-run-in-families","title":"Does Rett Syndrome Run in Families?"},{"lang":"en","slug":"what-causes-rett-syndrome-in-children","title":"What causes Rett syndrome in children?"},{"lang":"en","slug":"is-rett-syndrome-genetic-or-hereditary","title":"Is Rett Syndrome Genetic or Hereditary?"},{"lang":"en","slug":"can-rett-syndrome-be-detected-before-birth","title":"Can Rett Syndrome be detected before birth?"}],"summary":"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. AbilityScore® is part of Pinnacle’s developmental assessment. Diagnosis, where needed, requires an appropriately qualified healthcare professional.","answer_md":"*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.*\n\n## In short\nIn 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.\n\n## Understanding the genetics, gently\nRett 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:\n\n- **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.\n- **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.\n- **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.\n\nThis 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.**\n\n## Your practical next steps\n- **Ask for genetic counselling** — ideally before a next pregnancy. A genetic counsellor reviews your child's confirmed MECP2 result and your family history.\n- **Parental testing** can clarify whether a parent carries the change, turning uncertainty into a clear, personal risk figure.\n- **Prenatal and reproductive options** (such as prenatal testing) can be discussed once your family's specific risk is understood.\n\nKnowledge here is empowering — it replaces worry with a plan.\n\n## The Pinnacle way\nAbilityScore® is part of Pinnacle’s developmental assessment. Diagnosis, where needed, requires an appropriately qualified healthcare professional — 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®](/ask/what-is-the-abilityscore-and-how-is-it-calculated), and see how [occupational therapy](https://www.pinnacleblooms.org/best-occupational-therapy-center-india-proven-improvement-rate) supports daily skills and communication.\n\n## Trusted sources\nWHO 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.\n\n**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.\n\nThis is general information, not a diagnosis — individual assessment and diagnosis require an appropriately qualified healthcare professional.","canonical":"https://pinnacleblooms.org/ask/if-one-child-has-rett-syndrome-can-my-next-child-have-it-too","editorial":{"reviewed_at":"2026-06-11T20:12:18.613642+00:00","reviewed_by":null,"developed_by":"SETU Consortium · Pinnacle Blooms Network"},"alternates":[{"href":"https://pinnacleblooms.org/ask/if-one-child-has-rett-syndrome-can-my-next-child-have-it-too","lang":"en","indexable":true}],"dimensions":[{"key":"conditions","label":"Conditions"}],"meta_title":"Rett Syndrome: Can a Sibling Be Affected Too?","meta_robots":"index, follow, max-image-preview:large","everyday_tip":"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.","published_at":"2026-06-10T13:14:00.398329+00:00","reading_paths":[{"key":"understand","items":[{"lang":"en","slug":"is-rett-syndrome-genetic-or-hereditary","title":"Is Rett Syndrome Genetic or Hereditary?","reason":"Linked from this answer"},{"lang":"en","slug":"what-causes-rett-syndrome-in-children","title":"What causes Rett syndrome in children?","reason":"Linked from this answer"},{"lang":"en","slug":"how-does-rett-syndrome-affect-a-child-s-daily-life","title":"How Rett Syndrome Affects a Child's Daily Life","reason":"Same topic"},{"lang":"en","slug":"is-rett-syndrome-considered-a-disability","title":"Is Rett Syndrome considered a disability?","reason":"Same topic"},{"lang":"en","slug":"what-are-common-myths-about-rett-syndrome","title":"What are common myths about Rett Syndrome?","reason":"Same topic"},{"lang":"en","slug":"what-are-the-types-or-levels-of-rett-syndrome","title":"Types and Stages of Rett Syndrome","reason":"Same 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support","total":67},{"key":"home","items":[{"lang":"en","slug":"how-can-i-support-my-child-with-rett-syndrome-at-home","title":"How can I support my child with Rett Syndrome at home?","reason":"Same topic"}],"label":"At home & in everyday life","total":1}],"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.","authority_links":[{"url":"https://icd.who.int","label":"WHO ICD-11 classification of Rett Syndrome"},{"url":"https://www.healthychildren.org","label":"AAP HealthyChildren.org on genetic conditions in children"},{"url":"https://www.nice.org.uk","label":"NICE guidance on referral for clinical genetics counselling"}],"last_reviewed_at":"2026-06-10T13:14:00.398329+00:00","meta_description":"Most Rett Syndrome arises from a new, non-inherited gene change, 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