# NM_001040716.2(PC):c.787C>T (p.Arg263Ter)

https://sugi.bio/variant/pc-p-arg263ter

## Summary

**PC p.Arg263Ter (c.787C>T)** is classified **Pathogenic** in PC (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-07-20). Very rare (popmax 0.00267%, afr); Associated with Fetal anomalies with a likely genetic cause.

**At a glance:** Pathogenic · review: Multiple submitters · 2 submitters · 2 linked conditions · very rare (popmax 0.00267%, afr)

## For patients & families {#patients}

This is a change in the PC gene that is considered disease-causing, submitted by 2 submitters, and is linked to Fetal anomalies with a likely genetic cause.

*Reference information, not medical advice, and not a prediction for any individual. A genetic counselor or clinician can interpret what it means for you and your family.*

**Support & next steps:** [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [PC](https://sugi.bio/atlas/gene/PC/) |
| Protein change (HGVS p.) | p.Arg263Ter |
| Coding change (HGVS c.) | c.787C>T |
| MANE Select transcript | [NM_001040716](https://www.ncbi.nlm.nih.gov/nuccore/NM_001040716) |
| Variant type | single nucleotide variant |
| Location | chr11:66870418-66870418 (GRCh38) |
| ClinVar | [VCV3902729](https://www.ncbi.nlm.nih.gov/clinvar/variation/3902729/) |

**All HGVS expressions:** `NC_000011.10:g.66870418G>A`, `NC_000011.9:g.66637889G>A`, `NG_008319.1:g.92959C>T`, `NM_000920.4:c.787C>T`, `NM_001040716.2:c.787C>T`, `NM_022172.3:c.787C>T`

## Computational & population evidence {#evidence}

**Concordance:** 1 independent predictor **concordant** with the ClinVar classification.

- **Missense predictors (AlphaMissense/REVEL/SaProt) do not apply** to this variant type — they score amino-acid substitutions only. For non-missense variants the computational signal comes from conservation (below), not from a missing predictor score.
- Conservation: phyloP 5.696, GERP 1.18, phastCons 1 — highly conserved position (PP3-type support)
- Molecular consequence: **nonsense (stop-gain)** — a predicted loss-of-function variant. Gene population constraint: LOEUF 0.539, pLI 0.065118. *Descriptive; not an applied PVS1 code.*
- Nonsense-mediated decay: the premature termination codon is **in exon 9 of 23**, so the transcript is predicted to undergo NMD.
- CADD: **PHRED 37.0**. No single ClinGen-calibrated threshold exists and the expert panels that use CADD disagree — GUCY2D/AIPL1 require ≥ 20.0 for an untranslated-region variant, ABCA4 ≥ 28.1 for a synonymous or indel variant, the Pulmonary Hypertension panel imports Pejaver 2022's missense-calibrated numbers, and the Antibody Deficiencies panel declines CADD entirely for PIK3CD. CADD v1.7 also incorporates Zoonomia phyloP, so it partly re-expresses the conservation above. *Descriptive; no threshold applied.*
- SpliceAI: **not assessed** — no allele at this position is in our SpliceAI release, either because it lies outside the scored MANE transcript scope or because every allele is below Δ0.2. We cannot tell which, so this claims neither; absence is not evidence against a splicing effect.
- Population frequency (gnomAD v4.1): grpmax **0.00267%** (afr) · FAF95 0.000443% · FAF99 0.000166% · 2/74,910 in the highest group · 3/1,613,574 alleles overall — very rare (popmax 0.00267%, afr).

| Ancestry group | Allele frequency | 1 in |
| --- | --- | --- |
| African / African-American (grpmax) | 0.00267% | 37,455 |
| European (non-Finnish) | 8.47e-05% | 1,180,016 |

*Computational predictors are not independent (ClinGen Variant Classification guidance): AlphaMissense (Cheng et al. 2023) carries the ACMG weight for missense and conservation (phyloP/GERP/phastCons) for non-missense; REVEL (Pejaver-2022 calibrated strength bands) and SaProt (Su et al. 2023, structure-aware, ClinVar-independent protein language model, raw LLR) are shown as orthogonal agreement signals, not additive. For frequency, the gnomAD v4.1 grpmax filtering allele frequency (FAF95) is ClinGen's designated BA1/BS1 input (gnomAD v4 guidance v3.0, June 2025); BA1/BS1 thresholds are disease-specific, not a blanket 5%. Predictions, not a clinical determination.*

## Gene constraint & dosage {#gene-context}

**PC** population constraint: LOEUF 0.539, pLI 0.065118, missense-Z 3.7757; ClinGen dosage — haploinsufficiency gene assoc. with recessive phenotype, triplosensitivity Not yet evaluated/3. *Lower LOEUF and higher pLI indicate a gene that tolerates loss-of-function poorly; ClinGen dosage is the curated haploinsufficiency call.*

## Protein context {#protein}

Residue **263** lies in the biotin carboxylation domain; the atp-grasp domain; a β-strand.

AlphaFold model confidence (whole protein): pLDDT 90.53, 71% of residues very-high.

**10 experimental structure(s)** (PDB): [3BG3](https://www.rcsb.org/structure/3BG3), [3BG9](https://www.rcsb.org/structure/3BG9), [7WTA](https://www.rcsb.org/structure/7WTA), [7WTB](https://www.rcsb.org/structure/7WTB), [7WTC](https://www.rcsb.org/structure/7WTC), [7WTD](https://www.rcsb.org/structure/7WTD) — incl. mutant structure 3BG9.

## What this gene does {#gene-function}

*Describes the biological roles of PC (the gene this variant disrupts) — not effects measured for this specific variant. A damaging variant is expected to affect these functions and pathways; the degree depends on the variant.*

**How this variant is thought to act:** PC's established molecular role includes pyruvate carboxylase activity. p.Arg263Ter falls in the biotin carboxylation domain. In Reactome, PC is annotated in disease pathway(s) including **Defective HLCS causes multiple carboxylase deficiency**.

**Disease mechanism (Reactome):** PC loss or alteration is curated in [Defective HLCS causes multiple carboxylase deficiency](https://reactome.org/content/detail/R-HSA-3371599).

### Pathways affected {#pathways}

PC participates in **4 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Defective HLCS causes multiple carboxylase deficiency](https://reactome.org/content/detail/R-HSA-3371599) | curated |
| [Biotin transport and metabolism](https://reactome.org/content/detail/R-HSA-196780) | curated |
| [Gluconeogenesis](https://reactome.org/content/detail/R-HSA-70263) | curated |
| [Pyruvate metabolism](https://reactome.org/content/detail/R-HSA-70268) | curated |

### Molecular function & processes (GO — experimentally supported) {#go}

**Molecular function:** pyruvate carboxylase activity, identical protein binding.

**Biological process:** NADP+ metabolic process, negative regulation of gene expression, viral RNA genome packaging, viral release from host cell, NAD+ metabolic process, host-mediated activation of viral process.

## Clinical significance {#significance}

**Pathogenic** — review status Multiple submitters *(criteria provided, multiple submitters, no conflicts)*, last evaluated 2026-07-20.

**Submitter consensus:** unanimous (2/2 Pathogenic).

**Submission history:** 2 submissions (2025–2026); classifications have been stable.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Pathogenic | criteria provided, single submitter | clinical testing | 2025-05-23 |
| Genetics Laboratory, Great Ormond Street Hospital NHS Foundation Trust, North Thames Genomic Laboratory Hub | Pathogenic | criteria provided, single submitter | clinical testing | 2026-07-20 |

## Associated conditions {#conditions}

[Fetal anomalies with a likely genetic cause](https://sugi.bio/atlas/disease/fetal-anomalies-with-a-likely-genetic-cause/), [pyruvate carboxylase deficiency disease](https://sugi.bio/atlas/disease/pyruvate-carboxylase-deficiency-disease/).

**Reported phenotype names (ClinVar):** Fetal anomalies with a likely genetic cause, Pyruvate carboxylase deficiency, ATAXIA WITH LACTIC ACIDOSIS II, LEIGH NECROTIZING ENCEPHALOPATHY DUE TO PYRUVATE CARBOXYLASE DEFICIENCY, LEIGH SYNDROME DUE TO PYRUVATE CARBOXYLASE DEFICIENCY, PC DEFICIENCY, Pyruvate Carboxylase Deficiency Disease.

## Similar variants {#similar}

Related PC variant pages (same residue, condition, or type): [PC p.Arg263Gln](/variant/pc-p-arg263gln), [PC p.Arg263=](/variant/pc-p-arg263), [PC p.Arg263Gly](/variant/pc-p-arg263gly), [PC c.1368+1G>A](/variant/pc-c-1368-plus-1g-a), [PC c.1826-1G>C](/variant/pc-c-1826-minus-1g-c), [PC c.1983-116C>T](/variant/pc-c-1983-minus-116c-t), [PC c.633+2T>C](/variant/pc-c-633-plus-2t-c), [PC p.Ala610Thr](/variant/pc-p-ala610thr).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-14); gnomAD v4.1 (Broad Institute, built 2026-10-06); AlphaMissense (Cheng et al. 2023, © Google DeepMind — CC BY 4.0, built 2026-01-27); REVEL (Ioannidis et al. 2016 — ODbL, built 2026-07-13); SaProt (Su et al. 2023 — MIT, built 2026-10-14); SpliceAI (Illumina — free for non-commercial use, built 2026-10-13); CADD (Rentzsch et al. 2019, University of Washington — free for non-commercial use, built 2026-10-10); Conservation (phyloP/phastCons/GERP) (UCSC hg38 470-way mammal (Hiller Lab) + Ensembl Compara, built 2026-07-12); gnomAD Non-coding Constraint (Gnocchi) (Chen et al. 2024, Broad Institute — CC0, built 2026-10-11); gnomAD Regional Missense Constraint (Broad Institute — CC0, built 2026-10-13); Pangolin (Zeng & Li 2022 — CC BY 4.0, built 2026-10-11); Repeat regions (UCSC — RepeatMasker, TRF, segmental duplications, built 2026-10-11); ClinGen (ClinGen, built 2026-09-22); UniProt (CC BY 4.0); Reactome / GO (CC BY 4.0, built 2026-09-23); MaveDB (per-record license, built 2026-10-11); CIViC (CC0, built 2026-09-22); Orphanet (Orphanet, built 2026-06-12)

*Primary record: NCBI ClinVar (variation 3902729). Classifications reflect these databases as of the page's build date and may change. Free reference use — not medical advice; consult the primary submitters and a clinician.*