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atypical Rett syndrome - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

atypical Rett syndrome

MONDO:0017746

Also known as:Rett syndrome variantatypical RTTRett like syndrome

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Overview

A neurodevelopmental disorder that is diagnosed when a child presents with a Rett-like syndrome but does not fulfill all the diagnostic criteria for typical Rett syndrome (classic/typical RTT).

Clinical Trials2 registered · 2 recruiting

Patient Orgs1 organizations · Rett Syndrome Research Trust

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

No HPO annotations are available for this condition.

GeneReviews

Clinical Guidance

CDKL5 deficiency disorder (CDD) is a developmental and epileptic encephalopathy (DEE) characterized by severe early-onset epilepsy and motor, cognitive, visual, and autonomic disturbances [, , , , , , , ]. Movement disorders include chorea, dystonia, and stereotypical hand and leg movements . Cardiac involvement is nonspecific . Because the full spectrum of phenotypic severity is still emerging, especially given the possibility of mosaicism (in males and females) and the potential for skewed X-chromosome inactivation (in females), an individual with a de novo CDKL5 pathogenic variant may have a mild phenotype (for example, minimal epilepsy and global developmental delays). To date, approximately 500 individuals have been identified with CDD .

Diagnosis

Drawn from GeneReviews diagnostic guidelines, newborn screening panel status (RUSP), and ClinGen gene-disease validity classifications. Reflects current clinical evidence and consensus where available.

GeneReviews

Diagnostic Criteria

For the purposes of this GeneReview, the terms "male" and "female" are narrowly defined as the individual's biological sex at birth as it determines clinical care . Diagnostic criteria for CDKL5 deficiency disorder (CDD) have been proposed .

Suggestive Findings

CDD should be suspected in females and males with motor and cognitive developmental delays and epilepsy with onset in the first year of life (developmental delays and early-onset epilepsy constitute the minimal clinical diagnostic criteria proposed by ). Note: (1) Although females are more commonly affected than males with this X-linked disorder, the severity of manifestations in affected females and males can be equivalent.

Treatment

Compiled from FDA-approved drug records, orphan drug designations, and FDA Adverse Event Reporting System (FAERS) safety data. GeneReviews management guidance is included where available.

No approved treatments are currently available for atypical Rett syndrome. The disease remains an area of unmet medical need.

GeneReviews

Management Guidelines

International consensus recommendations for the assessment and management of individuals with CDKL5 deficiency disorder (CDD) have been published (full text). The management of individuals with CDD is complex and requires multiple specialty appointments; referral to a CDKL5 Center of Excellence may allow families to more easily coordinate care for affected individuals (to date, ten CDKL5 Centers of Excellence have been established in the United States).

Prognosis

Based on GeneReviews surveillance recommendations, HPO phenotype frequency and severity annotations, and published prevalence estimates from Orphanet and OMIM.

GeneReviews

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. In general, annual assessments by a medical home/primary care physician and specialists are needed.

Table 7.

CDKL5 Deficiency Disorder: Recommended Surveillance

System/Concern | Evaluation | Frequency

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

2 clinical trials registered, 2 recruiting. Interventions under study include other interventions. Research is primarily sponsored by academic and government institutions.

12 publications have been identified in PubMed for atypical Rett syndrome. Research spans Epidemiology / Natural History (33%), Case Report / Case Series (25%), and Basic Science / Preclinical (25%).

Research Type	Count	% of Total
Disease patterns and progression	4	33%

Data assembled from 5 of 12 sources · Last updated Sep 19, 2026, 5:32 PM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Patient Support

Patient Advocacy Groups

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Rett Syndrome Research TrustPrimary Focus

USWebsite ↗

Patient Advocacy Groups (PAGs) provide support, resources, and community for patients and caregivers.

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Medical References

External Resources

Orphanet

European rare disease database

Orphanet:3095

GARD

Genetic and Rare Diseases Info Center

GARD:4694

Questions for Your Care Team

→Are any of the 2 active clinical trials a good fit for my situation?
→Are there specialists or centers of excellence for this condition in my area?
→How can I connect with Rett Syndrome Research Trust and other patient organizations for support?

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GeneReviews

Differential Diagnosis

Table 3. Developmental and Epileptic Encephalopathies in the Differential Diagnosis of CDKL5 Deficiency Disorder

Gene(s)	Disorder	MOI
ARX	ARX-related DEE (OMIM 308350)	XL FOXG1
GABRA1	GABRA1-related DEE (OMIM 615744)	AD
GABRB3	GABRB3-related DEE (OMIM 617113)	AD
GABRG2	GABRG2-related DEE (OMIM 618396)	AD GRIN2A
KCNQ2	KCNQ2-related developmental epileptic encephalopathy (OMIM 613720)	AD KCNT1
MECP2	MECP2 classic Rett syndrome (See MECP2 Disorders.)	XL MECP2 duplication syndrome
PCDH19	PCDH19-related DEE (OMIM 300088)	XL SCN1A
SCN2A	SCN2A-related DEE (OMIM 613721)	AD SCN8A
SLC2A1	Classic glucose transporter type 1 deficiency syndrome (See Glucose Transporter Type 1 Deficiency Syndrome.)	AD(AR)1 STXBP1

Source: GeneReviews — "CDKL5 Deficiency Disorder"

atypical Rett syndrome

Overview

Clinical Presentation

Clinical Guidance

Diagnosis

Diagnostic Criteria

Suggestive Findings

Treatment

Management Guidelines

Prognosis

Surveillance Guidelines

Research Landscape

Patient Support

Patient Advocacy Groups

Medical References

External Resources

Orphanet

GARD

Subtypes

Related Diseases

Questions for Your Care Team

Questions for Your Care Team

Differential Diagnosis

Constitutional

Neurologic

Vision

Therapies Under Investigation

Clinical Trials

Neurologic

Feeding

Development

Psychiatric

Gastrointestinal

Respiratory

Musculoskeletal

Family/Community

Recent Publications

Latest News & Developments

A global literature review of comorbidities and concomitant supportive medications among individuals with Rett syndrome.

Family quality of life in the context of Rett syndrome: insights from Brazilian families.

Pilot study: the impact of simulation-based pediatric basic life support training on the performance of caregivers of children with Rett syndrome.

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