IL1RAPL1 encodes interleukin 1 receptor accessory protein like 1 (696 aa). May regulate secretion and presynaptic differentiation through inhibition of the activity of N-type voltage-gated calcium channel. May activate the MAP kinase JNK. Plays a role in neurite outgrowth. Highest expression in Nerve Tibial (2.4 TPM) and Brain Spinal cord cervical c-1 (1.7 TPM).

Intellectual disability, X-linked 21 is associated with mutations in the IL1RAPL1 gene on chromosome X.

The IL1RAPL1 protein participates in Interleukin-38 signaling, Receptor-type tyrosine-protein phosphatases, and Interleukin-1 family signaling pathways.

IL1RAPL1 is classified as a druggable target (Cell Surface, Druggable Genome, and Kinase categories) with score 0.0.

Genetic testing for IL1RAPL1 is available. Testing is considered confirmatory for diagnosis.

Biomarker and diagnostic research for intellectual disability, X-linked 21 has been reported in the published literature.

Phenotype severity distribution: 2 always present features, 1 very common feature, 5 common features.

No clinical trials have been registered for intellectual disability, X-linked 21.

57 publications have been identified in PubMed for intellectual disability, X-linked 21. Research spans Basic Science / Preclinical (39%), Epidemiology / Natural History (19%), and Clinical Trial Publication (13%).

Recent Publications

• Zhao X (2026). [PMID: 41525319](https://pubmed.ncbi.nlm.nih.gov/41525319/). *PLoS One*. [Basic Science / Preclinical]

• Liu N (2026). [PMID: 40884535](https://pubmed.ncbi.nlm.nih.gov/40884535/). *J Magn Reson Imaging*. [Epidemiology / Natural History]

• Burton BK (2026). [PMID: 41547052](https://pubmed.ncbi.nlm.nih.gov/41547052/). *Mol Genet Metab*. [Clinical Trial Publication]

• Alessandrì MG (2026). [PMID: 41776642](https://pubmed.ncbi.nlm.nih.gov/41776642/). *Orphanet J Rare Dis*. [Epidemiology / Natural History]

• Farooqi NNU (2026). [PMID: 41982083](https://pubmed.ncbi.nlm.nih.gov/41982083/). *Dev Neurobiol*. [Basic Science / Preclinical]

• Kumar A (2026). [PMID: 41946974](https://pubmed.ncbi.nlm.nih.gov/41946974/). *J Hum Genet*. [Clinical Trial Publication]

• Nelson MA (2026). [PMID: 39579284](https://pubmed.ncbi.nlm.nih.gov/39579284/). *J Autism Dev Disord*. [Clinical Trial Publication]

• Zhao Y (2026). [PMID: 41705901](https://pubmed.ncbi.nlm.nih.gov/41705901/). *Prenat Diagn*. [Basic Science / Preclinical]

• Brott JT (2026). [PMID: 42048321](https://pubmed.ncbi.nlm.nih.gov/42048321/). *PLoS One*. [Basic Science / Preclinical]

• Patel K (2026). [PMID: 40820925](https://pubmed.ncbi.nlm.nih.gov/40820925/). *J Pediatr Orthop*. [Basic Science / Preclinical]