# NM_001354640.2(CIROP):c.571C>T (p.Arg191Ter)

https://sugi.bio/variant/cirop-p-arg191ter

## Summary

**CIROP p.Arg191Ter (c.571C>T)** is classified **Pathogenic** in CIROP (ClinVar, No assertion criteria, 1 submitter; last evaluated 2022-03-15). Very rare (popmax 0.00699%, afr); Associated with heterotaxy, visceral, 12, autosomal.

**At a glance:** Pathogenic · review: No assertion criteria · rsID rs764530848 · 1 submitter · 1 linked condition · very rare (popmax 0.00699%, afr)

## For patients & families {#patients}

This is a change in the CIROP gene that is reported as disease-causing, but on limited review, submitted by 1 submitter, and is linked to heterotaxy, visceral, 12, autosomal.

*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:** [Condition overview & support (NIH GARD)](https://rarediseases.info.nih.gov/diseases/0026669/index) · [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [CIROP](https://sugi.bio/atlas/gene/CIROP/) |
| Protein change (HGVS p.) | p.Arg191Ter |
| Coding change (HGVS c.) | c.571C>T |
| MANE Select transcript | [NM_001354640](https://www.ncbi.nlm.nih.gov/nuccore/NM_001354640) |
| dbSNP | [rs764530848](https://www.ncbi.nlm.nih.gov/snp/rs764530848/) |
| Variant type | single nucleotide variant |
| Location | chr14:23103707-23103707 (GRCh38) |
| ClinVar | [VCV1344495](https://www.ncbi.nlm.nih.gov/clinvar/variation/1344495/) |

**All HGVS expressions:** `NC_000014.8:g.23572916G>A`, `NC_000014.9:g.23103707G>A`, `NM_001354640.2:c.571C>T`, `NM_001402427.1:c.580C>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 and, for splice-region changes, SpliceAI (below), not from a missing predictor score.
- SpliceAI predicts **donor loss** (Δ 0.37) — consistent with the pathogenic call
- Conservation: phyloP 3.418, GERP -1.27, phastCons 0.512 — highly conserved position (PP3-type support)
- Molecular consequence: **nonsense (stop-gain)** — a predicted loss-of-function variant. *Descriptive; not an applied PVS1 code.*
- Nonsense-mediated decay: the premature termination codon is **in exon 4 of 16**, so the transcript is predicted to undergo NMD.
- CADD: **PHRED 32.0**. 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 deltas (raw): acceptor loss **0.00**, donor loss **0.37**, acceptor gain **0.00**, donor gain **0.09**. Largest is donor loss, 32 bp away.
- SpliceAI deltas (masked): acceptor loss **0.00**, donor loss **0.00**, acceptor gain **0.00**, donor gain **0.09**.
  Masked SpliceAI — what Ensembl VEP and the Broad lookup serve by default — is below the reporting threshold here, so those tools show **no splice signal** for this allele. Masking zeroes a loss scored against a position that is not an annotated splice site, and a gain that merely strengthens an existing one, so the raw score above is describing a cryptic site rather than the site the variant sits on. *No ACMG code is assigned either way.*
- Pangolin: Δ**0.45** (loss), gain 0.11 / loss 0.45. Agrees with SpliceAI. An independent predictor to SpliceAI — a different model trained on different data. *Descriptive; ClinGen's SVI calibration covers SpliceAI, not Pangolin, so no ACMG code is assigned.*
- Population frequency (gnomAD v4.1): grpmax **0.00699%** (afr) · FAF95 0.00233% · FAF99 0.0014% · 4/57,258 in the highest group · 11/702,850 alleles overall — very rare (popmax 0.00699%, afr).

| Ancestry group | Allele frequency | 1 in |
| --- | --- | --- |
| African / African-American (grpmax) | 0.00699% | 14,315 |
| South Asian | 0.00592% | 16,898 |
| European (non-Finnish) | 0.000779% | 128,324 |

*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.*

## Protein context {#protein}

Residue **191** lies in a UniProt-annotated variant site (in htx12).

AlphaFold model confidence (whole protein): pLDDT 73.73, 35% of residues very-high.

## Clinical significance {#significance}

**Pathogenic** — review status No assertion criteria *(no assertion criteria provided)*, last evaluated 2022-03-15.

**Submitter consensus:** unanimous (1/1 Pathogenic).

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| OMIM | Pathogenic | no assertion criteria provided | literature only | 2022-03-15 |

## Associated conditions {#conditions}

[heterotaxy, visceral, 12, autosomal](https://sugi.bio/atlas/disease/heterotaxy-visceral-12-autosomal/).

**Reported phenotype names (ClinVar):** Heterotaxy, visceral, 12, autosomal.

## Similar variants {#similar}

Related CIROP variant pages (same residue, condition, or type): [CIROP p.Gln528Ter](/variant/cirop-p-gln528ter), [CIROP p.Arg22Ter](/variant/cirop-p-arg22ter), [CIROP p.Gly180Arg](/variant/cirop-p-gly180arg), [CIROP p.Gly511Glu](/variant/cirop-p-gly511glu), [CIROP p.Ser31Phe](/variant/cirop-p-ser31phe), [CIROP p.Tyr68Cys](/variant/cirop-p-tyr68cys), [CIROP p.Arg389Ile](/variant/cirop-p-arg389ile), [CIROP p.Ser384Leu](/variant/cirop-p-ser384leu).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-14); gnomAD v4.1 (Broad Institute, built 2026-10-14); 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 1344495). 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.*