SERPINB2

Chr 18

serpin family B member 2

Also known as: HsT1201, PAI, PAI-2, PAI2, PLANH2

NCBI Gene: 5055 ENSG00000197632 UniProt: P05120 OMIM: 173390

The SERPINB2 protein inhibits urokinase-type plasminogen activator, functioning as a serine protease inhibitor involved in regulating fibrinolysis and apoptosis. Mutations cause plasminogen activator inhibitor-2 deficiency, inherited in an autosomal recessive pattern. This gene shows very low constraint against loss-of-function variants, which is consistent with recessive inheritance where heterozygous carriers are typically unaffected.

OMIM ResearchSummary from RefSeq, UniProt

Predicted to enable serine-type endopeptidase inhibitor activity. Predicted to be involved in fibrinolysis and negative regulation of apoptotic process. Predicted to be located in extracellular region and plasma membrane. Predicted to be active in obsolete extracellular space. [provided by Alliance of Genome Resources, Jun 2026]

OMIM ResearchGenerating clinical summary…

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

1.53

LOEUF

Multiple*

Mechanism· predicted

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.53LOEUF

pLI 0.000

Z-score -0.09

OE 1.02 (0.70–1.53)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

-0.77Z-score

OE missense 1.15 (1.03–1.27)

257 obs / 224.4 exp

Tolerant

Tolerant to missense variation

Observed / Expected Ratios?

LoF OE?1.02 (0.70–1.53)

0≤0.351.4

Missense OE?1.15 (1.03–1.27)

0≤0.61.4

Synonymous OE?1.23

0≤1.21.6

LoF obs/exp: 17 / 16.6Missense obs/exp: 257 / 224.4Syn Z: -1.65

Background carrier burden — how many people carry a rare variant somewhere in SERPINB2?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 110

600 rare PASS variants

Rare truncating (LoF)

1 in 1,800

68 rare PASS variants

Rare synonymous (reference)

1 in 130

218 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for SERPINB2. A background rate for each class, not the frequency of any particular variant; thin-coverage exons undercount.

By genetic ancestry · 9 gnomAD groups · rare = under 0.1% in that group

Group	People	Missense	Truncating
European (non-Finnish)	~556k	1 in 130	1 in 2,000
South Asian	~43k	1 in 61	1 in 880
Remaining (unassigned)	~30k	1 in 56	1 in 860
European (Finnish)	~27k	1 in 330	none seen
Admixed American	~22k	1 in 98	1 in 2,200
African / African American	~21k	1 in 69	1 in 1,600
East Asian	~20k	1 in 120	1 in 800
Ashkenazi Jewish	~13k	1 in 290	≈ 1 in 3,200
Middle Eastern	~2,884	1 in 69	≈ 1 in 1,400

Each group is summed over the variants that are rare in that group. Grey ≈ figures rest on fewer than five expected carriers — too few to distinguish groups. Differences mostly reflect how many people were sampled and how much variation each ancestry carries, not disease risk.

Exome coverage (gnomAD): 6 of 7 coding exons well covered in gnomAD exomes; exon 5 marginal. Genomes: all 7.? see exons ↓