SERPINI1

Chr 3AD

serpin family I member 1

Also known as: HNS-S1, HNS-S2, PI12, neuroserpin

This gene encodes neuroserpin, a serine protease inhibitor that inhibits plasminogen activators and protects neurons from plasmin-mediated damage while regulating synaptic plasticity. Mutations cause familial encephalopathy with neuroserpin inclusion bodies (FENIB), an autosomal dominant condition characterized by progressive encephalopathy and epilepsy. The gene shows tolerance to loss-of-function variants (low pLI), suggesting the pathology arises through a different mechanism than simple protein loss.

OMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismADLOEUF 0.641 OMIM phenotype
Clinical SummarySERPINI1
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Gene-Disease Validity (ClinGen)
progressive myoclonus epilepsy · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.33) despite low pLI — interpret in context.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
0.64LOEUF
pLI 0.027
Z-score 2.68
OE 0.33 (0.180.64)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.42Z-score
OE missense 0.92 (0.821.03)
194 obs / 211.2 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.33 (0.180.64)
00.351.4
Missense OE0.92 (0.821.03)
00.61.4
Synonymous OE0.89
01.21.6
LoF obs/exp: 6 / 18.4Missense obs/exp: 194 / 211.2Syn Z: 0.70
DN
0.7132th %ile
GOF
0.7028th %ile
LOF
0.2093th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median
GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

SERPINI1 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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