C18ORF21
Chr 18ribonuclease MRP subunit p24
Also known as: C18orf21, HsT3108, PNAS-124, PNAS-131, XTP13
This protein is a specific component of the MRP ribonucleoprotein endoribonuclease complex that processes precursor ribosomal RNA. Mutations cause autosomal recessive primary microcephaly, typically presenting in infancy with severe intellectual disability and growth retardation. The gene shows low constraint against loss-of-function variants, which is consistent with the recessive inheritance pattern observed in affected families.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
ClinVar Variant Classifications
6 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories· variant type breakdown unavailable
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | — | — | — | — | 3 |
Likely Pathogenic | — | — | — | — | 1 |
VUS | — | — | — | — | 2 |
Likely Benign | — | — | — | — | 0 |
Benign | — | — | — | — | 0 |
| Total | — | 6 | |||
Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
C18ORF21 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →No open access results found
External Resources
Links to major genomics databases and tools