# NM_001005273.3(CHD3):c.2050C>T (p.Arg684Ter)

https://sugi.bio/variant/chd3-p-arg684ter

## Summary

**CHD3 p.Arg684Ter (c.2050C>T)** is classified **Pathogenic** in CHD3 (ClinVar, Single submitter, 1 submitter; last evaluated 2019-06-14). Absent from gnomAD v4.1; Associated with CHD3-related disorders.

**At a glance:** Pathogenic · review: Single submitter · 1 submitter · 1 linked condition · absent from gnomAD v4.1

## For patients & families {#patients}

This is a change in the CHD3 gene that is reported as disease-causing, but on limited review, submitted by 1 submitter, and is linked to CHD3-related disorders.

*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 | [CHD3](https://sugi.bio/atlas/gene/CHD3/) |
| Protein change (HGVS p.) | p.Arg684Ter |
| Coding change (HGVS c.) | c.2050C>T |
| MANE Select transcript | [NM_001005273](https://www.ncbi.nlm.nih.gov/nuccore/NM_001005273) |
| Variant type | single nucleotide variant |
| Location | chr17:7898101-7898101 (GRCh38) |
| ClinVar | [VCV4933412](https://www.ncbi.nlm.nih.gov/clinvar/variation/4933412/) |

**All HGVS expressions:** `NC_000017.10:g.7801419C>T`, `NC_000017.11:g.7898101C>T`, `NM_001005271.3:c.2227C>T`, `NM_001005273.3:c.2050C>T`, `NM_001437504.1:c.2227C>T`, `NM_001437507.1:c.2215C>T`, `NM_001437508.1:c.2215C>T`, `NM_001437509.1:c.2215C>T`, `NM_005852.4:c.2050C>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 3.918, GERP 0.878, phastCons 1 — highly conserved position (PP3-type support)
- Molecular consequence: **nonsense (stop-gain)** — a predicted loss-of-function variant. the gene is **loss-of-function-intolerant** (LOEUF 0.257, pLI 1), supporting a loss-of-function disease mechanism. *Descriptive; not an applied PVS1 code.*
- Nonsense-mediated decay: the premature termination codon is **in exon 12 of 40**, so the transcript is predicted to undergo NMD.
- CADD: **PHRED 40.0**. 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: **absent from gnomAD v4.1** — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

*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}

**CHD3** population constraint: LOEUF 0.257, pLI 1, missense-Z 8.4269. *Lower LOEUF and higher pLI indicate a gene that tolerates loss-of-function poorly; ClinGen dosage is the curated haploinsufficiency call.*

Curated gene–disease validity (ClinGen):

- **Snijders Blok-Campeau syndrome** — Definitive (AD)

## Protein context {#protein}

Residue **684** lies in a UniProt-annotated variant site (in snibcps).

AlphaFold model confidence (whole protein): pLDDT 63.21, 15% of residues very-high.

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

*Describes the biological roles of CHD3 (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:** CHD3's established molecular role includes transcription cis-regulatory region binding. In Reactome, CHD3 is annotated in disease pathway(s) including **Potential therapeutics for SARS**.

**Disease mechanism (Reactome):** CHD3 loss or alteration is curated in [Potential therapeutics for SARS](https://reactome.org/content/detail/R-HSA-9679191).

### Pathways affected {#pathways}

CHD3 participates in **13 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Potential therapeutics for SARS](https://reactome.org/content/detail/R-HSA-9679191) | curated |
| [HDACs deacetylate histones](https://reactome.org/content/detail/R-HSA-3214815) | curated |
| [Interaction of NuRD complexes with transcription factors](https://reactome.org/content/detail/R-HSA-9940951) | curated |
| [NuRD complex assembly](https://reactome.org/content/detail/R-HSA-9937850) | curated |
| [RNA Polymerase I Transcription Initiation](https://reactome.org/content/detail/R-HSA-73762) | curated |
| [Regulation of TP53 Activity through Acetylation](https://reactome.org/content/detail/R-HSA-6804758) | curated |
| [SUMOylation of chromatin organization proteins](https://reactome.org/content/detail/R-HSA-4551638) | curated |
| [Differentiation of naive CD4+ T cells to T helper 2 cells (Th2 cells)](https://reactome.org/content/detail/R-HSA-9976102) | electronic |
| [ERCC6 (CSB) and EHMT2 (G9a) positively regulate rRNA expression](https://reactome.org/content/detail/R-HSA-427389) | electronic |
| [Regulation of PTEN gene transcription](https://reactome.org/content/detail/R-HSA-8943724) | electronic |
| [Regulation of endogenous retroelements by KRAB-ZFP proteins](https://reactome.org/content/detail/R-HSA-9843940) | electronic |
| [Regulation of endogenous retroelements by Piwi-interacting RNAs (piRNAs)](https://reactome.org/content/detail/R-HSA-9845323) | electronic |
| [Transcriptional regulation of brown and beige adipocyte differentiation by EBF2](https://reactome.org/content/detail/R-HSA-9844594) | electronic |

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

**Molecular function:** transcription cis-regulatory region binding, RNA binding, ATP hydrolysis activity, ATP-dependent chromatin remodeler activity.

**Biological process:** negative regulation of transcription by RNA polymerase II, chromatin remodeling, spindle organization, centrosome cycle.

## Clinical significance {#significance}

**Pathogenic** — review status Single submitter *(criteria provided, single submitter)*, last evaluated 2019-06-14.

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

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Blueprint Genetics | Pathogenic | criteria provided, single submitter | clinical testing | 2019-06-14 |

## Associated conditions {#conditions}

[CHD3-related disorders](https://sugi.bio/atlas/disease/chd3-related-disorders/).

**Reported phenotype names (ClinVar):** CHD3-related disorders.

## Similar variants {#similar}

Related CHD3 variant pages (same residue, condition, or type): [CHD3 p.Arg1172Gln](/variant/chd3-p-arg1172gln), [CHD3 p.Arg1342Gln](/variant/chd3-p-arg1342gln), [CHD3 p.Arg985Gln](/variant/chd3-p-arg985gln), [CHD3 p.Arg1491His](/variant/chd3-p-arg1491his), [CHD3 p.Glu1653Ter](/variant/chd3-p-glu1653ter), [CHD3 p.Met1085Ile](/variant/chd3-p-met1085ile), [CHD3 p.Ala1289Thr](/variant/chd3-p-ala1289thr), [CHD3 p.Arg1342Trp](/variant/chd3-p-arg1342trp).

### 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 4933412). 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.*