Kisho is an information platform, not a medical provider. Nothing on this site constitutes medical advice, diagnosis, or treatment recommendations. All content is aggregated from publicly available sources (including ClinicalTrials.gov, PubMed, FDA.gov, and Orphanet) and is provided for informational purposes only. Clinical trial eligibility, treatment decisions, and any health-related actions should always be discussed with a qualified healthcare professional. Kisho does not endorse any specific therapy, organization, or clinical trial. Terms of use · Privacy policy
A nonsyndromic X-linked mental retardation (NS-XLMR) characterized by mild intellectual deficit. FRAXE is the most common form of NS-XLMR.
Features include always present findings: Delayed speech and language development and Intellectual disability; and common findings: Intrauterine growth retardation. 19 total HPO annotations.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Brain and nerves | 5 | Delayed speech and language development, Aggressive behavior, Compulsive behaviors |
Head and neck | 2 | Microcephaly, Long upper lip |
Growth and development | 2 | Short stature, Intrauterine growth retardation |
Arms and legs | 1 | Recurrent hand flapping |
Pregnancy and birth | 1 | Fetal distress |
Age of onset: before birth.
AFF2 encodes ALF transcription elongation factor 2 (1,311 aa). RNA-binding protein. Might be involved in alternative splicing regulation through an interaction with G-quartet RNA structure Highest expression in Brain Cerebellar Hemisphere (10.5 TPM) and Brain Cerebellum (7.6 TPM).
FRAXE intellectual disability is associated with mutations in the AFF2 gene on chromosome X.
AFF2 is classified as a druggable target with score 4.7.
Genetic testing for AFF2 is available. Testing is considered confirmatory for diagnosis.
Biomarker and diagnostic research for FRAXE intellectual disability has been reported in the published literature.
Phenotype severity distribution: 2 always present features, 1 common feature.
Estimated prevalence: 1-9 in 1,000,000 (Rare).
No clinical trials have been registered for FRAXE intellectual disability.
134 publications have been identified in PubMed for FRAXE intellectual disability. Kisho has analyzed 97 by research type. Research spans Review / Meta-Analysis (46%), Basic Science / Preclinical (31%), and Epidemiology / Natural History (7%).
Research Type | Count | % of Total |
|---|---|---|
Research summaries | 45 | 46% |
Laboratory research | 30 | 31% |
Disease patterns and progression | 7 | 7% |
Testing and diagnosis research | 5 | 5% |
New treatment approaches | 4 | 4% |
Patient case studies | 3 | 3% |
Other research | 2 | 2% |
Clinical study results | 1 | 1% |
Tkemladze T (2026). [PMID: 41044236](https://pubmed.ncbi.nlm.nih.gov/41044236/). *Eur J Hum Genet*. [Diagnostic / Biomarker]
Li Y (2026). [PMID: 40683950](https://pubmed.ncbi.nlm.nih.gov/40683950/). *Cell Death Differ*. [Basic Science / Preclinical]
Bourgeois JA (2026). [PMID: 41940304](https://pubmed.ncbi.nlm.nih.gov/41940304/). *Front Neurol*. [Review / Meta-Analysis]
Sarimski K (2026). [PMID: 41979662](https://pubmed.ncbi.nlm.nih.gov/41979662/). *Nervenarzt*. [Review / Meta-Analysis]
Kuruppath P (2026). [PMID: 41559886](https://pubmed.ncbi.nlm.nih.gov/41559886/). *Eur J Neurosci*. [Review / Meta-Analysis]
Nunes IS (2026). [PMID: 41087597](https://pubmed.ncbi.nlm.nih.gov/41087597/). *J Hum Genet*. [Case Report / Case Series]
Weissgold S (2026). [PMID: 42028919](https://pubmed.ncbi.nlm.nih.gov/42028919/). *J Intellect Disabil Res*. [Review / Meta-Analysis]
Arsenault J (2025). [PMID: 40232934](https://pubmed.ncbi.nlm.nih.gov/40232934/). *Cell Rep*. [Basic Science / Preclinical]
van der Lei MB (2025). [PMID: 40299377](https://pubmed.ncbi.nlm.nih.gov/40299377/). *Biomedicines*. [Review / Meta-Analysis]
Parkhill M (2025). [PMID: 40102109](https://pubmed.ncbi.nlm.nih.gov/40102109/). *Trends Pharmacol Sci*. [Review / Meta-Analysis]
Data assembled from 6 of 12 sources · Last updated Sep 20, 2026, 11:11 AM UTC
Online Mendelian Inheritance in Man
European rare disease database
Genetic and Rare Diseases Info Center
Common questions about FRAXE intellectual disability