SF3A3

Chr 1

splicing factor 3a subunit 3

Also known as: PRP9, PRPF9, SAP61, SF3a60

NCBI Gene: 10946ENSG00000183431UniProt: Q12874

This gene encodes subunit 3 of the splicing factor 3a protein complex. The splicing factor 3a heterotrimer includes subunits 1, 2 and 3 and is necessary for the in vitro conversion of 15S U2 snRNP into an active 17S particle that performs pre-mRNA splicing. Subunit 3 interacts with subunit 1 through its amino-terminus while the zinc finger domain of subunit 3 plays a role in its binding to the 15S U2 snRNP. This gene has a pseudogene on chromosome 20. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2016]

43
ClinVar variants
5
Pathogenic / LP
1.00
pLI score· haploinsufficient
0
Active trials
Clinical Summary— SF3A3
⚡
Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.
📋
ClinVar Variants
5 Pathogenic / Likely Pathogenic· 36 VUS of 43 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Dual constrained — LoF & missense intolerant
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
0.12LOEUF
pLI 1.000
Z-score 5.70
OE 0.03 (0.01–0.12)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
3.62Z-score
OE missense 0.37 (0.32–0.44)
99 obs / 264.6 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.03 (0.01–0.12)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.37 (0.32–0.44)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.97
0≤1.21.6
LoF obs/exp: 1 / 39.8Missense obs/exp: 99 / 264.6Syn Z: 0.22

ClinVar Variant Classifications

43 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic4
Likely Pathogenic1
VUS36
Likely Benign2
4
Pathogenic
1
Likely Pathogenic
36
VUS
2
Likely Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
0
0
4
0
4
Likely Pathogenic
0
0
1
0
1
VUS
0
33
3
0
36
Likely Benign
0
1
1
0
2
Benign
0
0
0
0
0
Total0349043

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

SF3A3 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools