# NM_004313.4(ARRB2):c.161T>C (p.Val54Ala)

https://sugi.bio/variant/arrb2-p-val54ala

## Summary

**ARRB2 p.Val54Ala (c.161T>C)** is classified **Uncertain significance** in ARRB2 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-10-02). AlphaMissense: likely pathogenic (0.8522); Very rare (popmax 0.000339%, nfe).

**At a glance:** Uncertain significance · review: Single submitter · 1 submitter · AlphaMissense likely pathogenic · very rare (popmax 0.000339%, nfe)

## For patients & families {#patients}

This is a change in the ARRB2 gene that is currently of uncertain significance — a definitive interpretation has not yet been established, submitted by 1 submitter.

*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 | [ARRB2](https://sugi.bio/atlas/gene/ARRB2/) |
| Protein change (HGVS p.) | p.Val54Ala |
| Coding change (HGVS c.) | c.161T>C |
| MANE Select transcript | [NM_004313](https://www.ncbi.nlm.nih.gov/nuccore/NM_004313) |
| Variant type | single nucleotide variant |
| Location | chr17:4716412-4716412 (GRCh38) |
| ClinVar | [VCV4643147](https://www.ncbi.nlm.nih.gov/clinvar/variation/4643147/) |

**All HGVS expressions:** `NC_000017.10:g.4619707T>C`, `NC_000017.11:g.4716412T>C`, `NM_001257328.2:c.161T>C`, `NM_001257329.2:c.161T>C`, `NM_001257330.2:c.161T>C`, `NM_001257331.2:c.116T>C`, `NM_001330064.2:c.-416T>C`, `NM_004313.4:c.161T>C`, `NM_199004.2:c.116T>C`, `NR_047516.2:n.220T>C`

## Computational & population evidence {#evidence}

**Concordance:** ClinVar classifies this **uncertain**; the computational predictors unanimously lean **damaging** — a triage signal, not a reclassification.

- AlphaMissense **likely pathogenic** (0.8522)
- REVEL 0.533 (indeterminate)
- SaProt LLR -11.791 (damaging) — agrees with AlphaMissense
- → **In-silico consensus:** AlphaMissense and SaProt both call this damaging; REVEL makes no call
- Conservation: phyloP 6.175, GERP 1.94, phastCons 1 — highly conserved (agrees)
- CADD: **PHRED 28.8**. 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.*
- Regional missense constraint: **o/e 0.70** across the covering region of the MANE Select transcript (4,710,722–4,721,036), spanning 10,314 bp. Chi-square p 5.2e-12. Describes the region, not this allele; gnomAD v4.1.1's own constrained determination. *Descriptive; no ACMG code 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 **0.000339%** (nfe) · FAF95 7.9e-05% · FAF99 5.4e-05% · 4/1,179,980 in the highest group · 4/1,613,838 alleles overall — very rare (popmax 0.000339%, nfe).

*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}

**ARRB2** population constraint: LOEUF 0.562, pLI 0.59516, missense-Z 2.6462. *Lower LOEUF and higher pLI indicate a gene that tolerates loss-of-function poorly; ClinGen dosage is the curated haploinsufficiency call.*

## Protein context {#protein}


AlphaFold model confidence (whole protein): pLDDT 83.97, 59% of residues very-high.

**1 experimental structure(s)** (PDB): [9UYM](https://www.rcsb.org/structure/9UYM).

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

*Describes the biological roles of ARRB2 (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:** ARRB2's established molecular role includes G protein-coupled receptor binding. In Reactome, ARRB2 is annotated in disease pathway(s) including **Paradoxical activation of RAF signaling by kinase inactive BRAF**, **Signaling by BRAF and RAF1 fusions**.

**Disease mechanism (Reactome):** ARRB2 loss or alteration is curated in [Paradoxical activation of RAF signaling by kinase inactive BRAF](https://reactome.org/content/detail/R-HSA-6802955), [Signaling by BRAF and RAF1 fusions](https://reactome.org/content/detail/R-HSA-6802952), [Signaling by RAF1 mutants](https://reactome.org/content/detail/R-HSA-9656223).

### Pathways affected {#pathways}

ARRB2 participates in **16 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Paradoxical activation of RAF signaling by kinase inactive BRAF](https://reactome.org/content/detail/R-HSA-6802955) | curated |
| ⚕ [Signaling by BRAF and RAF1 fusions](https://reactome.org/content/detail/R-HSA-6802952) | curated |
| ⚕ [Signaling by RAF1 mutants](https://reactome.org/content/detail/R-HSA-9656223) | curated |
| ⚕ [Signaling by high-kinase activity BRAF mutants](https://reactome.org/content/detail/R-HSA-6802948) | curated |
| ⚕ [Signaling by moderate kinase activity BRAF mutants](https://reactome.org/content/detail/R-HSA-6802946) | curated |
| ⚕ [Signaling downstream of RAS mutants](https://reactome.org/content/detail/R-HSA-9649948) | curated |
| [Cargo recognition for clathrin-mediated endocytosis](https://reactome.org/content/detail/R-HSA-8856825) | curated |
| [Clathrin-mediated endocytosis](https://reactome.org/content/detail/R-HSA-8856828) | curated |
| [G alpha (s) signalling events](https://reactome.org/content/detail/R-HSA-418555) | curated |
| [MAP2K and MAPK activation](https://reactome.org/content/detail/R-HSA-5674135) | curated |
| [TGFBR3 regulates TGF-beta signaling](https://reactome.org/content/detail/R-HSA-9839389) | curated |
| [Thrombin signalling through proteinase activated receptors (PARs)](https://reactome.org/content/detail/R-HSA-456926) | curated |
| [Ub-specific processing proteases](https://reactome.org/content/detail/R-HSA-5689880) | curated |
| [WNT5A-dependent internalization of FZD4](https://reactome.org/content/detail/R-HSA-5099900) | curated |
| [Activated NOTCH1 Transmits Signal to the Nucleus](https://reactome.org/content/detail/R-HSA-2122948) | electronic |
| [Activation of SMO](https://reactome.org/content/detail/R-HSA-5635838) | electronic |

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

**Molecular function:** G protein-coupled receptor binding, signaling receptor binding, enzyme binding, protein-macromolecule adaptor activity, ubiquitin protein ligase binding, angiotensin receptor binding.

**Biological process:** desensitization of G protein-coupled receptor signaling pathway, G protein-coupled receptor internalization, positive regulation of receptor internalization, transcription by RNA polymerase II, transforming growth factor beta receptor signaling pathway, protein ubiquitination.

## Clinical significance {#significance}

**Uncertain significance** — review status Single submitter *(criteria provided, single submitter)*, last evaluated 2025-10-02.

**Submitter consensus:** unanimous (1/1 Uncertain significance).

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Ambry Genetics | Uncertain significance | criteria provided, single submitter | clinical testing | 2025-10-02 |

**Reported phenotype names (ClinVar):** not specified, AllHighlyPenetrant.

## Similar variants {#similar}

Related ARRB2 variant pages (same residue, condition, or type): [ARRB2 p.Ile82=](/variant/arrb2-p-ile82), [ARRB2 p.Leu288=](/variant/arrb2-p-leu288), [ARRB2 p.Ala362Thr](/variant/arrb2-p-ala362thr), [ARRB2 p.Arg100Cys](/variant/arrb2-p-arg100cys), [ARRB2 p.Arg148Gln](/variant/arrb2-p-arg148gln), [ARRB2 p.Arg189Cys](/variant/arrb2-p-arg189cys), [ARRB2 p.Arg196Gln](/variant/arrb2-p-arg196gln), [ARRB2 p.Arg26Gln](/variant/arrb2-p-arg26gln).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-11); 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 2026-07-14); 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 4643147). 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.*