GPCPD1

gene
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Also known as KIAA1434GDE5GDPD6

Summary

GPCPD1 (glycerophosphocholine phosphodiesterase 1, HGNC:26957) is a protein-coding gene on chromosome 20p12.3, encoding Glycerophosphocholine phosphodiesterase GPCPD1 (Q9NPB8). May be involved in the negative regulation of skeletal muscle differentiation, independently of its glycerophosphocholine phosphodiesterase activity.

Predicted to enable glycerophosphocholine phosphodiesterase activity. Predicted to be involved in glycerophospholipid catabolic process. Predicted to act upstream of or within skeletal muscle tissue development. Predicted to be located in cytosol.

Source: NCBI Gene 56261 — RefSeq curated summary.

At a glance

  • GWAS associations: 8
  • Clinical variants (ClinVar): 82 total
  • MANE Select transcript: NM_019593

Identifiers

Gene identifiers

FieldValue
HGNC IDHGNC:26957
Approved symbolGPCPD1
Nameglycerophosphocholine phosphodiesterase 1
Location20p12.3
Locus typegene with protein product
StatusApproved
AliasesKIAA1434, GDE5, GDPD6
Ensembl geneENSG00000125772
Ensembl biotypeprotein_coding
OMIM614124
Entrez56261

Gene structure

Transcript identifiers

Ensembl transcripts: 19 — 14 protein_coding, 2 retained_intron, 2 nonsense_mediated_decay, 1 protein_coding_CDS_not_defined

ENST00000379019, ENST00000418646, ENST00000462080, ENST00000473797, ENST00000481038, ENST00000481690, ENST00000633552, ENST00000718343, ENST00000873924, ENST00000873925, ENST00000873926, ENST00000873927, ENST00000922545, ENST00000922546, ENST00000959744, ENST00000959745, ENST00000959746, ENST00000959747, ENST00000959748

RefSeq mRNA: 1 — MANE Select: NM_019593 NM_019593

CCDS: CCDS13090

Canonical transcript exons

ENST00000379019 — 20 exons

ExonStartEnd
ENSE0000102655356108425611006
ENSE0000165361555861945586269
ENSE0000347283255650175565078
ENSE0000347402255586845558819
ENSE0000349107355842815584322
ENSE0000349257255987255598821
ENSE0000349924955754135575545
ENSE0000350017455701475570239
ENSE0000351036855783805578611
ENSE0000351061555739155573969
ENSE0000351070955579455558105
ENSE0000352683155674835567560
ENSE0000352743955758165575978
ENSE0000354268755800085580131
ENSE0000358184655933275593411
ENSE0000362345655599405560076
ENSE0000362652555614655561530
ENSE0000363000655667335566772
ENSE0000378289756043645604440
ENSE0000403482955444395547850

Expression profiles

Bgee: expression breadth ubiquitous, 256 present calls, max score 97.53.

FANTOM5 (CAGE): breadth ubiquitous, TPM avg 49.9843 / max 1979.7405, expressed in 1812 samples.

FANTOM5 promoters (5 alternative TSS)

Promoter IDTPM avgSamples expressed
18631543.20311806
1863144.53221264
1863131.5351591
2089800.3880207
1863070.3260144

Top tissues by expression

256 total, by Bgee expression score (0-100, higher = more expressed):

TissueAnatomy IDExpression scoreQuality
palpebral conjunctivaUBERON:000181297.53gold quality
monocyteCL:000057697.00gold quality
bone marrowUBERON:000237196.75gold quality
leukocyteCL:000073896.61gold quality
bone marrow cellCL:000209296.37gold quality
endothelial cellCL:000011596.09gold quality
visceral pleuraUBERON:000240195.63gold quality
calcaneal tendonUBERON:000370195.36gold quality
tibialis anteriorUBERON:000138595.32gold quality
epithelial cell of pancreasCL:000008394.91gold quality
trabecular bone tissueUBERON:000248394.65gold quality
bloodUBERON:000017894.62gold quality
primary visual cortexUBERON:000243694.48gold quality
Brodmann (1909) area 23UBERON:001355494.12gold quality
middle temporal gyrusUBERON:000277194.00gold quality
spermCL:000001993.97gold quality
tonsilUBERON:000237293.94gold quality
cartilage tissueUBERON:000241893.73gold quality
cerebellar vermisUBERON:000472093.67gold quality
occipital lobeUBERON:000202193.57gold quality
tibiaUBERON:000097993.52gold quality
spleenUBERON:000210693.44gold quality
pancreatic ductal cellCL:000207993.13gold quality
saliva-secreting glandUBERON:000104493.00gold quality
esophagus squamous epitheliumUBERON:000692093.00gold quality
minor salivary glandUBERON:000183092.98gold quality
granulocyteCL:000009492.95gold quality
lungUBERON:000204892.95gold quality
parietal pleuraUBERON:000240092.88gold quality
adrenal tissueUBERON:001830392.88gold quality

Single-cell (SCXA)

Detected in 2 experiment(s), a significant marker in 2.

ExperimentMarker?Max mean expression
E-MTAB-3929yes192.31
E-ANND-3yes9.59

Regulation

Is transcription factor: no

miRNA regulators (miRDB)

234 targeting GPCPD1, top 30 by miRDB confidence (max_score; target_count = how many genes the miRNA targets in total — lower means more specific):

miRNAMax scoreAvg scoremiRNA target_count
HSA-MIR-190A-3P100.0080.355520
HSA-MIR-30A-5P100.0076.313233
HSA-MIR-30B-5P100.0076.293248
HSA-MIR-30C-5P100.0076.293248
HSA-MIR-30D-5P100.0076.323233
HSA-MIR-30E-5P100.0076.323242
HSA-MIR-196A-5P100.0068.16684
HSA-MIR-196B-5P100.0068.16681
HSA-MIR-29A-3P100.0073.111835
HSA-MIR-29B-3P100.0073.181833
HSA-MIR-29C-3P100.0073.151833
HSA-MIR-3163100.0077.238605
HSA-MIR-3646100.0073.565283
HSA-MIR-4262100.0073.263931
HSA-LET-7A-3P100.0074.033932
HSA-LET-7B-3P100.0074.083913
HSA-LET-7F-1-3P100.0074.023928
HSA-MIR-98-3P100.0074.083907
HSA-MIR-3120-5P100.0065.56965
HSA-MIR-656-3P100.0072.152788
HSA-MIR-5011-5P100.0083.465820
HSA-MIR-1252-5P100.0069.802774
HSA-MIR-6748-5P100.0065.811057
HSA-MIR-450099.9972.722367
HSA-MIR-118499.9968.191458
HSA-MIR-186-5P99.9970.833707
HSA-MIR-428299.9975.366408
HSA-MIR-181A-5P99.9972.962995
HSA-MIR-181B-5P99.9972.972996
HSA-MIR-181C-5P99.9972.952996

Literature-anchored findings (GeneRIF, showing 8)

  • common genetic variants in GPCPD1 are associated with scaling of visual cortical surface area in humans (PMID:22343285)
  • We have identified EDI3, a key enzyme controlling GPC and choline metabolism; Because inhibition of it corrects the GPC/PC ratio and decreases the migration capacity of tumor cells, it represents a possible target for therapeutic intervention. (PMID:22570503)
  • EDI3 links choline metabolism to integrin expression, cell adhesion and spreading (PMID:25482527)
  • Circular RNA circSNX6 promotes sunitinib resistance in renal cell carcinoma through the miR-1184/GPCPD1/ lysophosphatidic acid axis. (PMID:34626691)
  • Inhibiting the glycerophosphodiesterase EDI3 in ER-HER2+ breast cancer cells resistant to HER2-targeted therapy reduces viability and tumour growth. (PMID:36670508)
  • Hypoxia-induced GPCPD1 depalmitoylation triggers mitophagy via regulating PRKN-mediated ubiquitination of VDAC1. (PMID:36803235)
  • Gpcpd1-GPC metabolic pathway is dysfunctional in aging and its deficiency severely perturbs glucose metabolism. (PMID:38238601)
  • EDI3 knockdown in ER-HER2+ breast cancer cells reduces tumor burden and improves survival in two mouse models of experimental metastasis. (PMID:38816770)

Cross-species orthologs

9 orthologs

OrganismSymbolGene ID
danio_reriogpcpd1ENSDARG00000016011
mus_musculusGpcpd1ENSMUSG00000027346
rattus_norvegicusGpcpd1ENSRNOG00000053201
drosophila_melanogasterCG2818FBGN0031566
drosophila_melanogasterCG9394FBGN0034588
drosophila_melanogasterCG11619FBGN0036836
drosophila_melanogasterCG18135FBGN0036837
drosophila_melanogasterCG3942FBGN0038008
caenorhabditis_elegansWBGENE00011511

Protein

Protein identifiers

Glycerophosphocholine phosphodiesterase GPCPD1Q9NPB8 (reviewed: Q9NPB8)

Alternative names: Glycerophosphodiester phosphodiesterase 5

All UniProt accessions (4): Q9NPB8, A0A0J9YVP8, A0A0J9YY12, H0Y565

UniProt curated annotations — full annotation on UniProt →

Function. May be involved in the negative regulation of skeletal muscle differentiation, independently of its glycerophosphocholine phosphodiesterase activity.

Subcellular location. Cytoplasm. Cytosol.

Tissue specificity. Widely expressed, with highest expression in spinal chord.

Similarity. Belongs to the glycerophosphoryl diester phosphodiesterase family.

RefSeq proteins (1): NP_062539* (*=MANE)

Domains & families (InterPro)

IDNameType
IPR002044CBM20Domain
IPR013783Ig-like_foldHomologous_superfamily
IPR013784Carb-bd-like_foldHomologous_superfamily
IPR017946PLC-like_Pdiesterase_TIM-brlHomologous_superfamily
IPR030395GP_PDE_domDomain
IPR034839CBM20_GPCPD1Domain
IPR051578GDPDFamily
IPR057506C2_GPCPD1Domain

Pfam: PF00686, PF03009, PF25329

Enzyme classification (BRENDA):

  • EC 3.1.4.46 — glycerophosphodiester phosphodiesterase (BRENDA: 38 organisms, 62 substrates, 23 inhibitors, 29 Km, 19 kcat entries)

Substrate kinetics (BRENDA)

10 substrates with measured Km, best-characterized 10. Km ranges are aggregated across organisms/conditions.

SubstrateKm (mM)Measurements
BIS(P-NITROPHENYL) PHOSPHATE0.12–3.955
GLYCEROPHOSPHOCHOLINE0.036–25
P-NITROPHENYL PHOSPHATE0.12–495
GLYCEROPHOSPHOETHANOLAMINE0.2–0.223
GLYCEROPHOSPHOGLYCEROL0.2–0.623
BIS(P-NITROPHENYL PHOSPHATE)3.5–72
GLYCEROPHOSPHOINOSITOL0.392
GLYCEROPHOSPHOSERINE0.662
BIS(4-NITROPHENYL) PHOSPHATE3.561
BIS(GLYCEROPHOSPHO)GLYCEROL0.61

Catalyzed reactions (Rhea), 1 shown:

  • sn-glycerol 3-phosphocholine + H2O = sn-glycerol 3-phosphate + choline + H(+) (RHEA:16061)

UniProt features (19 total): strand 7, modified residue 3, domain 2, helix 2, binding site 2, chain 1, turn 1, sequence variant 1

Structure

Experimental structures (PDB)

1 structures.

PDBMethodResolution (Å)
2Z0BX-RAY DIFFRACTION2

Predicted structure (AlphaFold)

ModelpLDDTFraction very-high
AF-Q9NPB8-F187.450.70

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Ligand- & substrate-binding residues (2): 70; 88–89

Post-translational modifications (3): 175, 424, 608

Function

Pathways and Gene Ontology

Reactome pathways

2 pathways

IDPathway
R-HSA-1483115Hydrolysis of LPC
R-HSA-1483152Hydrolysis of LPE

MSigDB gene sets: 228 (showing top): TGGTGCT_MIR29A_MIR29B_MIR29C, AAGCAAT_MIR137, GOBP_PHOSPHOLIPID_METABOLIC_PROCESS, ACTACCT_MIR196A_MIR196B, GOBP_MUSCLE_TISSUE_DEVELOPMENT, IVANOVA_HEMATOPOIESIS_MATURE_CELL, MORI_IMMATURE_B_LYMPHOCYTE_UP, GOBP_ORGANOPHOSPHATE_METABOLIC_PROCESS, GOBP_GLYCEROLIPID_METABOLIC_PROCESS, GERY_CEBP_TARGETS, UEDA_PERIFERAL_CLOCK, GOBP_MUSCLE_STRUCTURE_DEVELOPMENT, INGRAM_SHH_TARGETS_UP, GOBP_SKELETAL_MUSCLE_ORGAN_DEVELOPMENT, GOBP_ORGANOPHOSPHATE_CATABOLIC_PROCESS

GO Biological Process (3): skeletal muscle tissue development (GO:0007519), glycerophospholipid catabolic process (GO:0046475), lipid metabolic process (GO:0006629)

GO Molecular Function (6): glycerophosphocholine phosphodiesterase activity (GO:0047389), starch binding (GO:2001070), protein binding (GO:0005515), phosphoric diester hydrolase activity (GO:0008081), hydrolase activity (GO:0016787), carbohydrate binding (GO:0030246)

GO Cellular Component (2): cytosol (GO:0005829), cytoplasm (GO:0005737)

Reactome top-level categories

Rollup of top-1 pathways:

CategoryPathways
Glycerophospholipid biosynthesis2

GO top-level categories

Rollup of top GO terms by namespace:

CategoryTerms
binding2
cellular anatomical structure2
striated muscle tissue development1
skeletal muscle organ development1
glycerophospholipid metabolic process1
phospholipid catabolic process1
glycerolipid catabolic process1
primary metabolic process1
phosphoric diester hydrolase activity1
polysaccharide binding1
phosphoric ester hydrolase activity1
catalytic activity1
cytoplasm1
intracellular anatomical structure1

Protein interactions and networks

STRING

1269 interactions, top by confidence (×1000):

Protein AProtein BPartner UniProtScore
GPCPD1GDPD5Q8WTR4589
GPCPD1CHPT1Q8WUD6588
GPCPD1CHKAP35790553
GPCPD1GDE1Q9NZC3536
GPCPD1TATDN3Q17R31530
GPCPD1CEPT1Q9Y6K0514
GPCPD1OTOL1A6NHN0472
GPCPD1ANGEL2Q5VTE6470
GPCPD1PCYT1BQ9Y5K3464
GPCPD1TDRPQ86YL5455
GPCPD1BEND7Q8N7W2453
GPCPD1TMX4Q9H1E5449
GPCPD1SHLD1Q8IYI0443
GPCPD1LYPLA1O75608434
GPCPD1UTP20O75691433

IntAct

7 interactions, top by confidence:

ABTypeScore
SLC35D3GPCPD1psi-mi:“MI:0915”(physical association)0.670
GPCPD1TK1psi-mi:“MI:0915”(physical association)0.370
SLC35D3ATP6V0A1psi-mi:“MI:0914”(association)0.350
PCBD1PTPDC1psi-mi:“MI:0914”(association)0.350
ZNF418ZNF195psi-mi:“MI:0914”(association)0.350
SLC35D3ERLIN2psi-mi:“MI:0914”(association)0.350

BioGRID (14): GPCPD1 (Affinity Capture-MS), GPCPD1 (Affinity Capture-MS), GPCPD1 (Affinity Capture-MS), GPCPD1 (Affinity Capture-MS), GPCPD1 (Affinity Capture-MS), LYPLA1 (Affinity Capture-Western), GPCPD1 (Affinity Capture-Western), VDAC1 (Affinity Capture-MS), VDAC1 (Affinity Capture-Western), GPCPD1 (Affinity Capture-Western), GPCPD1 (Affinity Capture-MS), GPCPD1 (Affinity Capture-RNA), GPCPD1 (Proximity Label-MS), GPCPD1 (Two-hybrid)

ESM2 similar proteins: A0JN80, A2RV18, A2VE39, D2HRF1, D3ZG52, D3ZVK1, E1BMP7, G3GTP0, I0IUP3, O02697, P0DM58, P37202, P42338, P48736, P49717, P49917, Q08162, Q0P4R5, Q0V9Q6, Q0V9R3, Q0WPN0, Q17632, Q3EBC8, Q3V3E1, Q5F310, Q5R5N8, Q5R6L3, Q5R981, Q5U2P0, Q5U2Z5, Q5ZKG3, Q6GN11, Q6NQJ6, Q80VJ4, Q8BTF7, Q8BTI9, Q8C0L9, Q8C0S1, Q8CI75, Q8N1G2

Diamond homologs: A0A1D8PNZ7, A2X8A7, A2XNL6, A2Y8U6, P43585, P77736, Q02979, Q10003, Q10B79, Q21407, Q2V4F9, Q658H5, Q680A6, Q6EPQ3, Q74ZH9, Q80VJ4, Q8C0L9, Q8RB32, Q94A21, Q9NPB8, Q9SGA2, Q9ULT8, O14169, O90760, Q10728, Q1RJ28, Q5UQV3, Q9DBR7, Q9JL55, Q9JL56, Q9NZC3, O07592, Q9C104, P37965, Q3T0T0, Q86WC6, Q9D119, Q9FLM1

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

82 variants total. Per-class counts are floors (≥ shown; pagination cap):

ClassificationCount (floor)
Pathogenic0
Likely pathogenic0
Uncertain significance57
Likely benign4
Benign2

Top pathogenic / likely-pathogenic (0)

SpliceAI

3629 predictions. Top by Δscore:

VariantEffectΔscore
20:5557966:A:Cdonor_gain1.0000
20:5557969:C:CAdonor_gain1.0000
20:5557975:T:Adonor_gain1.0000
20:5557985:T:Adonor_gain1.0000
20:5558678:A:Cdonor_gain1.0000
20:5558680:TTA:Tdonor_loss1.0000
20:5558681:TA:Tdonor_loss1.0000
20:5558682:A:ACdonor_gain1.0000
20:5558682:A:ATdonor_loss1.0000
20:5558682:AC:Adonor_gain1.0000
20:5558683:C:CGdonor_gain1.0000
20:5558683:CC:Cdonor_gain1.0000
20:5558683:CCA:Cdonor_gain1.0000
20:5558683:CCAG:Cdonor_gain1.0000
20:5558683:CCAGT:Cdonor_gain1.0000
20:5558815:GAACC:Gacceptor_gain1.0000
20:5558817:ACC:Aacceptor_gain1.0000
20:5558818:CC:Cacceptor_gain1.0000
20:5558818:CCC:Cacceptor_gain1.0000
20:5558819:CC:Cacceptor_gain1.0000
20:5558820:C:CAacceptor_loss1.0000
20:5558820:C:CCacceptor_gain1.0000
20:5558820:C:Tacceptor_gain1.0000
20:5558821:T:Aacceptor_loss1.0000
20:5559938:A:ACdonor_gain1.0000
20:5559939:C:CCdonor_gain1.0000
20:5559939:CATT:Cdonor_gain1.0000
20:5560076:CCTAG:Cacceptor_gain1.0000
20:5561578:C:CTacceptor_gain1.0000
20:5561579:A:Tacceptor_gain1.0000

AlphaMissense

4446 scored. Top likely-pathogenic:

VariantProtein changeam_pathogenicity
20:5558021:A:GW585R0.999
20:5558021:A:TW585R0.999
20:5558104:C:TG557E0.999
20:5558105:C:AG557W0.999
20:5558105:C:GG557R0.999
20:5558105:C:TG557R0.999
20:5558735:T:AR539S0.999
20:5558735:T:GR539S0.999
20:5558736:C:GR539T0.999
20:5558807:C:AK515N0.999
20:5558807:C:GK515N0.999
20:5559945:G:CC509W0.999
20:5559960:A:CF504L0.999
20:5559960:A:TF504L0.999
20:5559962:A:GF504L0.999
20:5559981:C:AR497S0.999
20:5559981:C:GR497S0.999
20:5561483:T:AK459N0.999
20:5561483:T:GK459N0.999
20:5561484:T:AK459I0.999
20:5567496:A:GL405P0.999
20:5573925:G:TA349D0.999
20:5573948:A:CN341K0.999
20:5573948:A:TN341K0.999
20:5575440:C:TG325D0.999
20:5575443:C:GR324P0.999
20:5575447:G:CH323D0.999
20:5575449:C:TG322D0.999
20:5580105:A:GW126R0.999
20:5580105:A:TW126R0.999

dbSNP variants (sampled 300 via entrez): RS1000046252 (20:5554494 C>T), RS1000111597 (20:5593406 A>T), RS1000208723 (20:5611785 C>G,T), RS1000268171 (20:5548016 A>T), RS1000269042 (20:5548780 G>A), RS1000324098 (20:5605576 C>T), RS1000378169 (20:5598540 A>C), RS1000395282 (20:5604968 CAA>C), RS1000472586 (20:5580827 C>T), RS1000473843 (20:5555368 G>A), RS1000556405 (20:5578894 T>A,C), RS1000630136 (20:5587874 C>T), RS1000662111 (20:5592546 C>T), RS1000675275 (20:5560684 C>T), RS1000818703 (20:5585206 G>A)

Disease associations

OMIM: gene MIM:614124 | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

8 associations (top):

StudyTraitp-value
GCST001411_1Occipital cortical area (total cortical area interaction)6.000000e-09
GCST006473_2Diffusing capacity of the lung for carbon monoxide traits4.000000e-07
GCST006616_4Uterine fibroid number (single vs multiple)1.000000e-06
GCST009391_2087Metabolite levels2.000000e-06
GCST010204_144Low density lipoprotein cholesterol levels1.000000e-11
GCST010243_12Apolipoprotein B levels1.000000e-13
GCST010245_100LDL cholesterol levels2.000000e-08
GCST012232_37Lipoprotein (a) levels7.000000e-10

EFO canonical traits (8, from GWAS)

EFO IDTrait name
EFO:0004771visual cortical surface area measurement
EFO:0008381total cortical area measurement
EFO:0009369diffusing capacity of the lung for carbon monoxide
EFO:0009410uterine fibroid measurement
EFO:0010373phosphatidylcholine 32:1 measurement
EFO:0004611low density lipoprotein cholesterol measurement
EFO:0004615apolipoprotein B measurement
EFO:0006925lipoprotein A measurement

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

58 total (human), top 30 by PubMed support.

ChemicalActions (top 5)PubMed papers
bisphenol Aaffects cotreatment, decreases expression, affects expression, increases expression4
sodium arsenitedecreases expression, affects cotreatment, increases abundance3
Air Pollutantsaffects expression, increases abundance, increases expression3
Arsenicaffects methylation, affects cotreatment, decreases expression, increases abundance3
Valproic Acidaffects expression, increases expression3
Cyclosporineincreases expression3
methylmercuric chlorideincreases expression2
Acetaminophenaffects expression, increases expression2
Cadmiumincreases abundance, increases expression, decreases expression2
Folic Aciddecreases expression, affects cotreatment, increases expression2
Nickelincreases expression2
Ozoneaffects expression, increases abundance2
Phenylmercuric Acetateaffects cotreatment, decreases expression2
GSK-J4increases expression1
FR900359decreases phosphorylation1
triphenyl phosphateaffects expression1
tris(1,3-dichloro-2-propyl)phosphateincreases expression1
manganese chloridedecreases expression, increases abundance, affects cotreatment1
resorcinoldecreases expression1
di-n-butylphosphoric acidaffects expression1
perfluoro-n-nonanoic acidincreases expression1
4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamideaffects cotreatment, decreases expression1
clothianidinincreases expression1
ICG 001increases expression1
dorsomorphinaffects cotreatment, decreases expression1
jinfukangaffects cotreatment, increases expression1
prothioconazoleincreases expression1
NSC 689534affects binding, increases expression1
4-(4-((5-(4,5-dimethyl-2-nitrophenyl)-2-furanyl)methylene)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzoic acidincreases expression1
Sunitinibincreases expression1

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.

No linked Atlas pages yet — the cross-entity mesh grows as the corpus expands.