# NM_002461.3(MVD):c.232C>A (p.Arg78=)

https://sugi.bio/variant/mvd-p-arg78

## Summary

**MVD p.Arg78= (c.232C>A)** is classified **Benign** in MVD (ClinVar, Multiple submitters, 3 submitters; last evaluated 2021-09-05). Common (popmax 74.5%, amr) — too common for a highly-penetrant pathogenic allele; Associated with porokeratosis 7, multiple types.

**At a glance:** Benign · review: Multiple submitters · rsID rs2279258 · 3 submitters · 1 linked condition · common (popmax 74.5%, amr) — too common for a highly-penetrant pathogenic allele

## For patients & families {#patients}

This is a change in the MVD gene that is classified as benign — not considered disease-causing, submitted by 3 submitters, and is linked to porokeratosis 7, multiple types.

*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.*

|  |  |
| --- | --- |
| Typical inheritance (of this condition) | Autosomal dominant |
| Age of onset (of this condition) | Adolescent, Adult, Childhood, Elderly |
| Diagnostic panels | MVD is a diagnostic-grade gene on 3 Genomics England panels |

**Commonly reported features of Disseminated superficial actinic porokeratosis** (across patients with this condition; presentation varies — frequencies from Orphanet):

- Porokeratosis — Very frequent (99-80%)
- Cutaneous photosensitivity — Frequent (79-30%)
- Pruritus — Occasional (29-5%)
- Squamous cell carcinoma — Occasional (29-5%)

**Support & next steps:** [Condition overview & support (NIH GARD)](https://rarediseases.info.nih.gov/diseases/0015838/index) · [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [MVD](https://sugi.bio/atlas/gene/MVD/) |
| Protein change (HGVS p.) | p.Arg78= |
| Coding change (HGVS c.) | c.232C>A |
| MANE Select transcript | [NM_002461](https://www.ncbi.nlm.nih.gov/nuccore/NM_002461) |
| dbSNP | [rs2279258](https://www.ncbi.nlm.nih.gov/snp/rs2279258/) |
| Variant type | single nucleotide variant |
| Location | chr16:88657939-88657939 (GRCh38) |
| ClinVar | [VCV1321178](https://www.ncbi.nlm.nih.gov/clinvar/variation/1321178/) |

**All HGVS expressions:** `NC_000016.10:g.88657939G>T`, `NC_000016.9:g.88724347G>T`, `NG_052674.1:g.10215C>A`, `NM_002461.2:c.232C>A`, `NM_002461.3:c.232C>A`

## Computational & population evidence {#evidence}

**Concordance:** Evidence sources **disagree** — common (popmax 74.5%, amr) — too common for a highly-penetrant pathogenic allele.

- **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 7.315, GERP 1.91, phastCons 1 — highly conserved position (PP3-type support)
- CADD: **PHRED 11.49**. 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 **74.5%** (amr) · FAF95 73.9% · FAF99 73.6% · 44,688/60,012 in the highest group · 1,010,494/1,613,370 alleles overall — common (popmax 74.5%, amr) — too common for a highly-penetrant pathogenic allele.

| Ancestry group | Allele frequency | 1 in |
| --- | --- | --- |
| Admixed American (grpmax) | 74.5% | 1 |
| Finnish (not grpmax-eligible) | 69.4% | 1 |
| Amish (not grpmax-eligible) | 68.5% | 1 |
| European (non-Finnish) | 65.5% | 2 |
| Remaining individuals (not grpmax-eligible) | 60.5% | 2 |
| East Asian | 60.1% | 2 |
| Ashkenazi Jewish (not grpmax-eligible) | 57.9% | 2 |
| Middle Eastern | 57.4% | 2 |
| South Asian | 42.3% | 2 |
| African / African-American | 31.8% | 3 |

*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}

**MVD** population constraint: LOEUF 1.706, pLI 2.7752e-23, missense-Z -2.2325. *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 **78** lies in an α-helix; a binding site.

AlphaFold model confidence (whole protein): pLDDT 92.52, 83% of residues very-high.

**1 experimental structure(s)** (PDB): [3D4J](https://www.rcsb.org/structure/3D4J).

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

*Describes the biological roles of MVD (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:** MVD's established molecular role includes diphosphomevalonate decarboxylase activity.


### Pathways affected {#pathways}

MVD participates in **3 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| [Activation of gene expression by SREBF (SREBP)](https://reactome.org/content/detail/R-HSA-2426168) | curated |
| [Lanosterol biosynthesis](https://reactome.org/content/detail/R-HSA-9969896) | curated |
| [Synthesis of dolichyl-phosphate](https://reactome.org/content/detail/R-HSA-446199) | curated |

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

**Molecular function:** diphosphomevalonate decarboxylase activity, Hsp70 protein binding, protein homodimerization activity.

**Biological process:** positive regulation of cell population proliferation, isoprenoid biosynthetic process.

## Clinical significance {#significance}

**Benign** — review status Multiple submitters *(criteria provided, multiple submitters, no conflicts)*, last evaluated 2021-09-05.

**Submitter consensus:** unanimous (3/3 Benign).

**Submission history:** 3 submissions (2019–2021); classifications have been stable.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Genome-Nilou Lab | Benign | criteria provided, single submitter | clinical testing | 2021-09-05 |
| Breakthrough Genomics, Breakthrough Genomics | Benign | criteria provided, single submitter | not provided |  |
| PreventionGenetics, part of Exact Sciences | Benign | no assertion criteria provided | clinical testing | 2019-09-24 |

## Associated conditions {#conditions}

[porokeratosis 7, multiple types](https://sugi.bio/atlas/disease/porokeratosis-7-multiple-types/).

**Reported phenotype names (ClinVar):** Porokeratosis 7, multiple types, MVD-related disorder, not provided, none provided, POROK7, MVD-related condition.

## Similar variants {#similar}

Related MVD variant pages (same residue, condition, or type): [MVD p.Arg78Gln](/variant/mvd-p-arg78gln), [MVD p.Phe249Ser](/variant/mvd-p-phe249ser), [MVD c.1013+1G>T](/variant/mvd-c-1013-plus-1g-t), [MVD c.1014-1G>T](/variant/mvd-c-1014-minus-1g-t), [MVD p.Asn292Ser](/variant/mvd-p-asn292ser), [MVD c.1013+5G>T](/variant/mvd-c-1013-plus-5g-t), [MVD c.604-7C>T](/variant/mvd-c-604-minus-7c-t), [MVD p.Glu230Lys](/variant/mvd-p-glu230lys).

### 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 1321178). 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.*