# NM_001378615.1(CC2D2A):c.2773C>T (p.Arg925Ter)

https://sugi.bio/variant/cc2d2a-p-arg925ter

## Summary

**CC2D2A p.Arg925Ter (c.2773C>T)** is classified **Pathogenic/Likely pathogenic** in CC2D2A (ClinVar, Multiple submitters, 5 submitters; last evaluated 2025-01-06). Ultra-rare (popmax 0.0164%, mid); Associated with CC2D2A-related disorder.

**At a glance:** Pathogenic/Likely pathogenic · review: Multiple submitters · rsID rs386833748 · 5 submitters · 4 linked conditions · ultra-rare (popmax 0.0164%, mid)

## For patients & families {#patients}

This is a change in the CC2D2A gene that is considered likely disease-causing, submitted by 5 submitters, and is linked to CC2D2A-related disorder.

*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 | [CC2D2A](https://sugi.bio/atlas/gene/CC2D2A/) |
| Protein change (HGVS p.) | p.Arg925Ter |
| Coding change (HGVS c.) | c.2773C>T |
| MANE Select transcript | [NM_001378615](https://www.ncbi.nlm.nih.gov/nuccore/NM_001378615) |
| dbSNP | [rs386833748](https://www.ncbi.nlm.nih.gov/snp/rs386833748/) |
| Variant type | single nucleotide variant |
| Location | chr4:15557451-15557451 (GRCh38) |
| ClinVar | [VCV56300](https://www.ncbi.nlm.nih.gov/clinvar/variation/56300/) |

**All HGVS expressions:** `LRG_697:g.92586C>T`, `LRG_697t1:c.2773C>T`, `NC_000004.11:g.15559074C>T`, `NC_000004.12:g.15557451C>T`, `NG_013035.1:g.92586C>T`, `NM_001080522.2:c.2773C>T`, `NM_001378615.1:c.2773C>T`, `NM_001378617.1:c.2626C>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 2.202, GERP 2.01, phastCons 1 — highly conserved position (PP3-type support)
- Molecular consequence: **nonsense (stop-gain)** — a predicted loss-of-function variant. Gene population constraint: LOEUF 0.854, pLI 6.8922e-26. *Descriptive; not an applied PVS1 code.*
- Nonsense-mediated decay: the premature termination codon is **in exon 21 of 37**, so the transcript is predicted to undergo NMD.
- CADD: **PHRED 39.0**. 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: **no splice effect predicted**. SpliceAI outputs four numbers per variant, not one: acceptor loss, donor loss, acceptor gain, donor gain (DS_AL / DS_DL / DS_AG / DS_DG). A loss score is an existing splice site weakened or destroyed; a gain score is a new site created or an existing one strengthened. The release publishes its own filter rule, which we read from the dataset rather than assume: an allele is reported only if the largest of its four deltas reaches 0.2. No allele at this position is in the release, so all four are under 0.2 for every alternate allele here. No figure is shown because none was read: the bound is deduced from that absence. It is a result, not a gap in our data, because the release scores every possible substitution across the transcripts it covers (Ensembl MANE v1.4) before it filters, so what survives for a gene is one continuous stretch. What is measured is that this position sits inside the stretch covered for CC2D2A (2,098 scored positions, the nearest 12 bases away); what is taken from the release's own description, rather than measured, is that coverage inside that stretch is continuous. On that, SpliceAI did score it. *ClinGen's SVI treats the largest of the four as evidence against a splicing effect at or below 0.1, where it may support BP4, and as uninformative between 0.1 and 0.2. We cannot tell which applies here, so these SpliceAI data support neither BP4 nor PP3; that is a statement about this evidence alone, not about the variant's other evidence.*
- Population frequency (gnomAD v4.1): grpmax **0.0164%** (mid) · FAF95 6.8e-05% · FAF99 1.9e-05% · 1/6,080 in the highest group · 7/1,612,388 alleles overall — ultra-rare (popmax 0.0164%, mid).

| Ancestry group | Allele frequency | 1 in |
| --- | --- | --- |
| Middle Eastern (grpmax) | 0.0164% | 6,080 |
| Ashkenazi Jewish (not grpmax-eligible) | 0.00339% | 29,528 |
| Remaining individuals (not grpmax-eligible) | 0.0016% | 62,406 |
| African / African-American | 0.00134% | 74,792 |
| European (non-Finnish) | 0.000254% | 393,122 |

*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}

**CC2D2A** population constraint: LOEUF 0.854, pLI 6.8922e-26, missense-Z 0.46757; ClinGen dosage — haploinsufficiency gene assoc. with recessive phenotype, triplosensitivity 0/3. *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):

- **ciliopathy** — Definitive (AR)

## Protein context {#protein}

Residue **925** lies in a UniProt-annotated variant site (in rp93).

AlphaFold model confidence (whole protein): pLDDT 69.46, 13% of residues very-high.

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

*Describes the biological roles of CC2D2A (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.*


### Pathways affected {#pathways}

CC2D2A participates in **1 Reactome pathway** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| [Anchoring of the basal body to the plasma membrane](https://reactome.org/content/detail/R-HSA-5620912) | curated |

## Clinical significance {#significance}

**Pathogenic/Likely pathogenic** — review status Multiple submitters *(criteria provided, multiple submitters, no conflicts)*, last evaluated 2025-01-06.

**Submitter consensus:** conflicting (3 Likely pathogenic, 2 Pathogenic).

**Submission history:** 5 submissions (2018–2025); classifications have differed over time.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Illumina Laboratory Services, Illumina | Likely pathogenic | criteria provided, single submitter | clinical testing | 2018-12-18 |
| GeneDx | Pathogenic | criteria provided, single submitter | clinical testing | 2024-02-26 |
| Labcorp Genetics (formerly Invitae), Labcorp | Pathogenic | criteria provided, single submitter | clinical testing | 2025-01-06 |
| Blueprint Genetics | Likely pathogenic | criteria provided, single submitter | clinical testing | 2022-11-03 |
| Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM) | Likely pathogenic | no assertion criteria provided | not provided |  |

## Associated conditions {#conditions}

[CC2D2A-related disorder](https://sugi.bio/atlas/disease/cc2d2a-related-disorder/), [Meckel syndrome, type 6](https://sugi.bio/atlas/disease/meckel-syndrome-type-6/), [Joubert syndrome](https://sugi.bio/atlas/disease/joubert-syndrome/), [Meckel syndrome](https://sugi.bio/atlas/disease/meckel-syndrome/).

**Reported phenotype names (ClinVar):** CC2D2A-related disorder, Meckel syndrome, type 6, not provided, Joubert syndrome, Meckel-Gruber syndrome, CC2D2A-related disorders, CC2D2A-related condition, none provided, DYSENCEPHALIA SPLANCHNOCYSTICA, GRUBER SYNDROME.

## Similar variants {#similar}

Related CC2D2A variant pages (same residue, condition, or type): [CC2D2A p.Arg925Gln](/variant/cc2d2a-p-arg925gln), [CC2D2A p.Arg925Leu](/variant/cc2d2a-p-arg925leu), [CC2D2A p.Arg925Pro](/variant/cc2d2a-p-arg925pro), [CC2D2A c.1017+1G>A](/variant/cc2d2a-c-1017-plus-1g-a), [CC2D2A c.123+2T>G](/variant/cc2d2a-c-123-plus-2t-g), [CC2D2A c.1359+1G>A](/variant/cc2d2a-c-1359-plus-1g-a), [CC2D2A c.1359+1G>C](/variant/cc2d2a-c-1359-plus-1g-c), [CC2D2A c.1466+1G>A](/variant/cc2d2a-c-1466-plus-1g-a).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-14); gnomAD v4.1 (Broad Institute, built 2026-10-15); 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 56300). 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.*