CDKL5 deficiency disorder (CDD) is the current, consensus-based medical name for this rare neurodevelopmental condition, which was historically referred to as "atypical Rett syndrome." While you may still encounter older terms in medical literature or clinical records, CDKL5 deficiency disorder is the standardized term used by clinicians and researchers to describe the condition caused by mutations in the CDKL5 gene. What are the common synonyms for CDKL5 deficiency disorder? Because the clinical understanding of CDKL5 deficiency disorder has evolved rapidly since the gene was first identified, patients and families often encounter multiple names in their medical records. Historically, because many patients presented with features overlapping with Rett syndrome, the condition was classified as a variant. Today, CDKL5 deficiency disorder is recognized as a distinct clinical entity. Common synonyms and historical terms include: Atypical Rett syndrome (Hanefeld variant) Early-onset seizure variant of Rett syndrome CDKL5-related epilepsy X-linked infantile spasm syndrome (sometimes used in genetic contexts) How is the condition classified in medical databases? To ensure accuracy in clinical settings, medical professionals rely on standardized classification systems. Using these official identifiers can help when searching for the latest research on CDKL5 deficiency disorder: OMIM (Online Mendelian Inheritance in Man): Listed under #300672 as "CDKL5 Deficiency Disorder." Orphanet: Classified as ORPHA:140939, specifically indexed as "CDKL5 deficiency disorder." ICD-10/11: While coding varies, it is frequently categorized under genetic disorders involving epilepsy or neurodevelopmental delay. Why does the terminology for CDKL5 deficiency disorder vary? The shift in nomenclature reflects advancements in genetic testing. Before the specific CDKL5 gene was isolated in 2004, patients were often diagnosed based purely on symptoms, leading to the "atypical Rett" label. As our ability to map the genome improved, the medical community moved toward naming the condition after the specific gene involved. This shift is crucial for CDKL5 deficiency disorder because it separates the condition from classic Rett syndrome, which is typically caused by mutations in the MECP2 gene. Next steps Consult a geneticist or neurologist to ensure your medical records reflect the most current terminology for CDKL5 deficiency disorder. Connect with the 71 members of the DiseaseMaps.org community who share lived experiences with this diagnosis. Visit the International Foundation for CDKL5 Research (IFCR) for the latest clinical trial information. Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition. References NIH Genetic and Rare Diseases Information Center (GARD): CDKL5 deficiency disorder Orphanet: CDKL5 deficiency disorder (ORPHA:140939) OMIM (Online Mendelian Inheritance in Man): #300672 International Foundation for CDKL5 Research (IFCR)

Short answer · Medically reviewed summary · Last updated: 2026-05-08

CDKL5 deficiency disorder (CDD) is the current, consensus-based medical name for this rare neurodevelopmental condition, which was historically referred to as "atypical Rett syndrome." While you may still encounter older terms in medical literature or clinical records, CDKL5 deficiency disorder is the standardized term used by clinicians and researchers to describe the condition caused by mutations in the CDKL5 gene. What are the common synonyms for CDKL5 deficiency disorder? Because the clinical understanding of CDKL5 deficiency disorder has evolved rapidly since the gene was first identified, patients and families often encounter multiple names in their medical records. Historically, because many patients presented with features overlapping with Rett syndrome, the condition was classified as a variant.

CDKL5 synonyms

Name: CDKL5 synonyms
Creator: DiseaseMaps Editorial Team
Published: 2016-07-10UTC06:22:26.0000000

Other names for CDKL5: synonyms, acronyms and related terms used by doctors and patients.

CDKL5 deficiency disorder (CDD) is the current, consensus-based medical name for this rare neurodevelopmental condition, which was historically referred to as "atypical Rett syndrome." While you may still encounter older terms in medical literature or clinical records, CDKL5 deficiency disorder is the standardized term used by clinicians and researchers to describe the condition caused by mutations in the CDKL5 gene.

What are the common synonyms for CDKL5 deficiency disorder?

Because the clinical understanding of CDKL5 deficiency disorder has evolved rapidly since the gene was first identified, patients and families often encounter multiple names in their medical records. Historically, because many patients presented with features overlapping with Rett syndrome, the condition was classified as a variant. Today, CDKL5 deficiency disorder is recognized as a distinct clinical entity. Common synonyms and historical terms include:

Atypical Rett syndrome (Hanefeld variant)

Early-onset seizure variant of Rett syndrome

CDKL5-related epilepsy

X-linked infantile spasm syndrome (sometimes used in genetic contexts)

How is the condition classified in medical databases?

To ensure accuracy in clinical settings, medical professionals rely on standardized classification systems. Using these official identifiers can help when searching for the latest research on CDKL5 deficiency disorder:

OMIM (Online Mendelian Inheritance in Man): Listed under #300672 as "CDKL5 Deficiency Disorder."

Orphanet: Classified as ORPHA:140939, specifically indexed as "CDKL5 deficiency disorder."

ICD-10/11: While coding varies, it is frequently categorized under genetic disorders involving epilepsy or neurodevelopmental delay.

Why does the terminology for CDKL5 deficiency disorder vary?

The shift in nomenclature reflects advancements in genetic testing. Before the specific CDKL5 gene was isolated in 2004, patients were often diagnosed based purely on symptoms, leading to the "atypical Rett" label. As our ability to map the genome improved, the medical community moved toward naming the condition after the specific gene involved. This shift is crucial for CDKL5 deficiency disorder because it separates the condition from classic Rett syndrome, which is typically caused by mutations in the MECP2 gene.

Next steps

Consult a geneticist or neurologist to ensure your medical records reflect the most current terminology for CDKL5 deficiency disorder.

Connect with the 71 members of the DiseaseMaps.org community who share lived experiences with this diagnosis.

Visit the International Foundation for CDKL5 Research (IFCR) for the latest clinical trial information.

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.