# What is Rett Syndrome, and its ICD-11 features in early childhood?

Canonical: https://pinnacleblooms.org/ask/what-is-rett-syndrome-and-what-are-its-icd-11-features-in-early-childhood
Publisher: Pinnacle Blooms Network / Bharath Healthcare Laboratories Private Limited

Rett syndrome (ICD-11 LD90.0) is a neurodevelopmental disorder, usually from MECP2 variants and predominantly affecting females, marked by normal early development followed by regression with loss of purposeful hand use and language, stereotypic midline hand movements, gait abnormality and head-growth deceleration. Seizures and autonomic features are common, warranting prompt neurology referral.

*A girl with normal early milestones who then plateaus and loses purposeful hand use — that clinical arc is the signature of Rett syndrome.*

## In short
Rett syndrome (ICD-11 **LD90.0**) is a neurodevelopmental disorder, in most classic cases caused by pathogenic *MECP2* variants, affecting predominantly females. It is characterised by a period of apparently normal early development followed by regression, with loss of acquired purposeful hand skills and spoken language, gait abnormalities, and the emergence of stereotypic midline hand movements. It is a clinically and genetically defined condition — not a therapy-first label.

## The science, briefly
The ICD-11 framing reflects the recognised natural history. After largely typical development through roughly 6–18 months, early childhood features include:
- **Regression** — loss of previously acquired purposeful hand use and expressive language
- **Hand stereotypies** — characteristic midline wringing, washing, clapping or mouthing movements
- **Gait and motor abnormalities** — apraxia, truncal ataxia, or loss of ambulation
- **Deceleration of head growth** (acquired microcephaly in classic presentations)
- Frequently associated features: breathing irregularities when awake, bruxism, seizures, autonomic dysfunction and disrupted sleep

Genetic confirmation (*MECP2*) supports classic Rett; atypical variants involve *CDKL5* and *FOXG1*. Because seizures and autonomic involvement are common, this warrants prompt **paediatric neurology** referral alongside developmental support.

## The Pinnacle way
Developmental measurement supports care planning; diagnosis requires an appropriately qualified healthcare professional., under qualified clinician care — never from an app or online form. For confirmed cases we coordinate multidisciplinary support spanning [Rett syndrome care](/rett-syndrome), [occupational therapy](https://www.pinnacleblooms.org/best-occupational-therapy-center-india-proven-improvement-rate) for hand function and posture, and a baseline via the [clinician-administered AbilityScore®](/ask/what-is-the-abilityscore-and-how-is-it-calculated).

## Trusted sources
WHO ICD-11 (LD90.0); WHO ICF functioning framework; consensus diagnostic criteria for Rett syndrome.

**Next step —** For a child showing developmental regression or hand stereotypies, expedite neurology referral and [partner with Pinnacle](/rett-syndrome) for coordinated developmental support.

This is general information, not a diagnosis — individual assessment and diagnosis require an appropriately qualified healthcare professional.

## Sources
- WHO ICD-11 — Rett syndrome (LD90.0): https://icd.who.int/
- WHO — neurodevelopmental disorders overview: https://www.who.int/

## Connected topics and perspectives
- Conditions: https://pinnacleblooms.org/ask/conditions
- Doctor: https://pinnacleblooms.org/ask/lens/stakeholder/doctor
- Context: https://pinnacleblooms.org/ask/lens/domain/context
- Definition: https://pinnacleblooms.org/ask/lens/intent/definition
- Screen: https://pinnacleblooms.org/ask/lens/lifecycle/screen
- Special Education: https://pinnacleblooms.org/ask/lens/route/special-education
- Early Clarity: https://pinnacleblooms.org/ask/lens/empowerment/early_clarity

## Related question paths

### Understand the subject
- What is Rett Syndrome?: https://pinnacleblooms.org/ask/what-is-rett-syndrome
- ICD-11 Classification of Rett Syndrome (LD90.0): https://pinnacleblooms.org/ask/what-is-the-icd-11-classification-for-rett-syndrome
- What is Rett Syndrome, and what does it look like in early childhood?: https://pinnacleblooms.org/ask/what-is-rett-syndrome-and-what-does-it-look-like-in-early-childhood
- What is the SNOMED CT concept for Rett Syndrome?: https://pinnacleblooms.org/ask/what-is-the-snomed-ct-concept-for-rett-syndrome
- How Rett Syndrome Affects a Child's Daily Life: https://pinnacleblooms.org/ask/how-does-rett-syndrome-affect-a-child-s-daily-life
- Is Rett Syndrome considered a disability?: https://pinnacleblooms.org/ask/is-rett-syndrome-considered-a-disability
- Is Rett Syndrome Genetic or Hereditary?: https://pinnacleblooms.org/ask/is-rett-syndrome-genetic-or-hereditary
- What are common myths about Rett Syndrome?: https://pinnacleblooms.org/ask/what-are-common-myths-about-rett-syndrome
- Types and Stages of Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-types-or-levels-of-rett-syndrome
- What causes Rett syndrome in children?: https://pinnacleblooms.org/ask/what-causes-rett-syndrome-in-children
- Early Intervention Outcomes in Rett Syndrome (Under 7): https://pinnacleblooms.org/ask/what-does-current-research-show-about-early-intervention-outcomes-for-rett-syndrome-in-children-under-7
- Conditions That Occur Alongside Rett Syndrome: https://pinnacleblooms.org/ask/what-other-conditions-often-occur-alongside-rett-syndrome

### Recognise signs & concerns
- Early indicators of Rett syndrome for paediatricians: https://pinnacleblooms.org/ask/what-early-indicators-of-rett-syndrome-should-a-paediatrician-watch-for
- Rett Syndrome Red Flags Warranting Referral: https://pinnacleblooms.org/ask/what-clinical-red-flags-for-rett-syndrome-warrant-referral-in-a-young-child
- When to refer suspected Rett syndrome for developmental therapy: https://pinnacleblooms.org/ask/when-should-a-doctor-refer-a-child-with-suspected-rett-syndrome-for-developmental-therapy
- Can Rett Syndrome Be Cured?: https://pinnacleblooms.org/ask/can-rett-syndrome-be-cured
- Can Rett Syndrome Be Prevented?: https://pinnacleblooms.org/ask/can-rett-syndrome-be-prevented
- Rett Syndrome in Boys: https://pinnacleblooms.org/ask/do-boys-show-rett-syndrome-differently
- Do girls show Rett Syndrome differently?: https://pinnacleblooms.org/ask/do-girls-show-rett-syndrome-differently
- Spotting Possible Rett Syndrome Early: https://pinnacleblooms.org/ask/how-can-a-frontline-health-worker-spot-a-child-with-possible-rett-syndrome-early
- Should I be worried my child might have Rett Syndrome?: https://pinnacleblooms.org/ask/should-i-be-worried-my-child-might-have-rett-syndrome
- Early Signs of Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-early-signs-of-rett-syndrome
- Early signs of Rett syndrome in a 1-year-old boy: https://pinnacleblooms.org/ask/what-are-the-early-signs-of-rett-syndrome-in-a-1-year-old-boy
- Early Signs of Rett Syndrome in a 1-Year-Old Girl: https://pinnacleblooms.org/ask/what-are-the-early-signs-of-rett-syndrome-in-a-1-year-old-girl

### Explore causes & influences
- Known contributing factors for Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-known-contributing-factors-for-rett-syndrome-in-early-childhood
- Are boys more likely to have Rett Syndrome?: https://pinnacleblooms.org/ask/are-boys-more-likely-to-have-rett-syndrome
- Are girls more likely to have Rett Syndrome?: https://pinnacleblooms.org/ask/are-girls-more-likely-to-have-rett-syndrome
- Early Intervention for Rett Syndrome, UNCRPD & the SDGs: https://pinnacleblooms.org/ask/how-does-early-intervention-for-rett-syndrome-advance-un-child-rights-uncrpd-and-the-sdgs
- What Causes Rett Syndrome in Young Children?: https://pinnacleblooms.org/ask/what-causes-rett-syndrome-in-young-children
- Cost-effectiveness of early therapy for Rett Syndrome in young children: https://pinnacleblooms.org/ask/what-is-the-cost-effectiveness-of-early-therapy-for-rett-syndrome-in-young-children
- Prevalence and Public-Health Burden of Rett Syndrome in India: https://pinnacleblooms.org/ask/what-is-the-prevalence-and-public-health-burden-of-rett-syndrome-among-young-children-in-india

### Understand assessment
- Standardised tools for assessing Rett syndrome in early childhood: https://pinnacleblooms.org/ask/which-standardised-tools-are-used-to-assess-rett-syndrome-in-early-childhood
- Rett Syndrome Diagnostic Pathway in Children Under 7: https://pinnacleblooms.org/ask/what-is-the-recommended-screening-and-diagnostic-pathway-for-rett-syndrome-in-children-under-7
- How AbilityScore Tracks Progress in a Child with Rett Syndrome: https://pinnacleblooms.org/ask/how-does-abilityscore-track-progress-in-a-child-with-rett-syndrome
- How Rett Syndrome Is Assessed in a Young Child: https://pinnacleblooms.org/ask/how-is-rett-syndrome-assessed-in-a-young-child
- How Rett Syndrome Is Assessed in Children Under 7: https://pinnacleblooms.org/ask/how-is-rett-syndrome-assessed-in-children-under-7
- What an AbilityScore® of 0–100 means for a child with Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-0-100-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 100–200 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-100-200-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 200–300 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-200-300-mean-for-a-child-with-rett-syndrome
- AbilityScore 300–400 in Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-300-400-mean-for-a-child-with-rett-syndrome
- What an AbilityScore of 400–500 Means in Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-400-500-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 500–600 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-500-600-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 600–700 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-600-700-mean-for-a-child-with-rett-syndrome

### Explore therapy & support
- How Grandparents and Caregivers Can Support a Child with Rett Syndrome: https://pinnacleblooms.org/ask/as-a-grandparent-or-caregiver-how-can-i-support-a-child-with-rett-syndrome-day-to-day
- Can a Child with Rett Syndrome Attend a Mainstream School?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-attend-a-mainstream-school
- Can a Child with Rett Syndrome Attend a Regular School?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-attend-a-regular-school
- Can a Child with Rett Syndrome Live Independently?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-grow-up-to-live-independently
- Helping a Child with Rett Syndrome Take Part and Learn: https://pinnacleblooms.org/ask/how-can-a-classroom-teacher-help-a-child-with-rett-syndrome-take-part-and-learn
- Identifying and Supporting Children Under 7 with Rett Syndrome: https://pinnacleblooms.org/ask/how-can-a-district-early-intervention-programme-identify-and-support-children-under-7-with-rett-syndrome
- How can a teacher include a child with Rett Syndrome in a mainstream classroom?: https://pinnacleblooms.org/ask/how-can-a-teacher-include-and-support-a-young-child-with-rett-syndrome-in-a-mainstream-classroom
- How does therapy help a child with Rett Syndrome make progress?: https://pinnacleblooms.org/ask/how-does-therapy-help-a-child-with-rett-syndrome-make-progress
- How is Rett Syndrome diagnosed in a child?: https://pinnacleblooms.org/ask/how-is-rett-syndrome-diagnosed-in-a-child
- How is Rett Syndrome supported through therapy?: https://pinnacleblooms.org/ask/how-is-rett-syndrome-supported-through-therapy
- Rett Syndrome AbilityScore®: What to Do Next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-0-100-what-should-we-do-next
- Rett Syndrome with an AbilityScore of 100–200: your next step: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-100-200-what-should-we-do-next

### At home & in everyday life
- How can I support my child with Rett Syndrome at home?: https://pinnacleblooms.org/ask/how-can-i-support-my-child-with-rett-syndrome-at-home