# NM_199242.3(UNC13D):c.811C>T (p.Pro271Ser)

https://sugi.bio/variant/unc13d-p-pro271ser

## Summary

**UNC13D p.Pro271Ser (c.811C>T)** is classified **Conflicting classifications of pathogenicity** in UNC13D (ClinVar, Conflicting submitters, 6 submitters; last evaluated 2026-01-25). AlphaMissense: ambiguous (0.3476); Rare (popmax 0.191%, sas); Associated with autoinflammatory syndrome.

**At a glance:** Conflicting classifications of pathogenicity · review: Conflicting submitters · rsID rs139564938 · 6 submitters · 2 linked conditions · AlphaMissense ambiguous · rare (popmax 0.191%, sas)

## For patients & families {#patients}

This is a change in the UNC13D gene that is of uncertain or conflicting significance (submitters disagree on it), submitted by 6 submitters, and is linked to autoinflammatory syndrome.

*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.*

|  |  |
| --- | --- |
| Clinical trials | 4 registered for this condition — see ClinicalTrials.gov |

**Support & next steps:** [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [UNC13D](https://sugi.bio/atlas/gene/UNC13D/) |
| Protein change (HGVS p.) | p.Pro271Ser |
| Coding change (HGVS c.) | c.811C>T |
| MANE Select transcript | [NM_199242](https://www.ncbi.nlm.nih.gov/nuccore/NM_199242) |
| dbSNP | [rs139564938](https://www.ncbi.nlm.nih.gov/snp/rs139564938/) |
| Variant type | single nucleotide variant |
| Location | chr17:75840272-75840272 (GRCh38) |
| ClinVar | [VCV719448](https://www.ncbi.nlm.nih.gov/clinvar/variation/719448/) |

**All HGVS expressions:** `LRG_122:g.9446C>T`, `LRG_122t1:c.811C>T`, `NC_000017.10:g.73836353G>A`, `NC_000017.11:g.75840272G>A`, `NG_007266.1:g.9446C>T`, `NM_199242.3:c.811C>T`

## Computational & population evidence {#evidence}

**Concordance:** AlphaMissense makes no call; REVEL and SaProt both call this tolerated; AlphaMissense is indeterminate — descriptive only.

- AlphaMissense **ambiguous** (0.3476) — no call either way
- REVEL 0.188 (benign-leaning)
- SaProt LLR -5.283 (tolerated)
- → **In-silico consensus:** REVEL and SaProt both call this tolerated; AlphaMissense is indeterminate
- Conservation: phyloP 11.602, phastCons 1 — highly conserved
- CADD: **PHRED 26.0**. 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.*
- Regional missense constraint: **o/e 0.90** across the covering region of the MANE Select transcript (75,836,359–75,844,337), spanning 7,978 bp. Chi-square p 0.017. Describes the region, not this allele; gnomAD v4.1.1's own constrained determination. *Descriptive; no ACMG code 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 UNC13D (1,301 scored positions, the nearest 11 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 **0.191%** (sas) · FAF95 0.168% · FAF99 0.159% · 174/91,084 in the highest group · 630/1,613,988 alleles overall — rare (popmax 0.191%, sas).

| Ancestry group | Allele frequency | 1 in |
| --- | --- | --- |
| South Asian (grpmax) | 0.191% | 523 |
| Middle Eastern | 0.0828% | 1,208 |
| European (non-Finnish) | 0.0344% | 2,906 |
| Remaining individuals (not grpmax-eligible) | 0.0304% | 3,289 |
| Finnish (not grpmax-eligible) | 0.0266% | 3,758 |
| African / African-American | 0.00666% | 15,009 |
| Admixed American | 0.005% | 20,007 |
| Ashkenazi Jewish (not grpmax-eligible) | 0.00338% | 29,608 |

*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}

**UNC13D** population constraint: LOEUF 0.923, pLI 4.4142e-31, missense-Z 0.44179. *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):

- **familial hemophagocytic lymphohistiocytosis 3** — Definitive (AR)

## Protein context {#protein}

Residue **271** lies in the 'interaction with rab27a' region.

AlphaFold model confidence (whole protein): pLDDT 85.04, 63% of residues very-high.

**1 experimental structure(s)** (PDB): [9LA9](https://www.rcsb.org/structure/9LA9).

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

*Describes the biological roles of UNC13D (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:** UNC13D's established molecular role includes small GTPase binding. p.Pro271Ser falls in the interaction with rab27a region.


### Pathways affected {#pathways}

UNC13D participates in **1 Reactome pathway** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| [Neutrophil degranulation](https://reactome.org/content/detail/R-HSA-6798695) | curated |

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

**Molecular function:** small GTPase binding.

**Biological process:** regulation of mast cell degranulation, positive regulation of exocytosis, positive regulation of regulated secretory pathway.

## Clinical significance {#significance}

**Conflicting classifications of pathogenicity** — review status Conflicting submitters *(criteria provided, conflicting classifications)*, last evaluated 2026-01-25.

**Submitter consensus:** conflicting (3 Likely benign, 2 Uncertain significance, 1 Benign).

**Submission history:** 6 submissions (2017–2026); classifications have differed over time.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Illumina Laboratory Services, Illumina | Uncertain significance | criteria provided, single submitter | clinical testing | 2017-04-27 |
| Genetic Services Laboratory, University of Chicago | Likely benign | criteria provided, single submitter | clinical testing | 2021-12-23 |
| Genome Diagnostics Laboratory, The Hospital for Sick Children | Uncertain significance | criteria provided, single submitter | clinical testing | 2021-03-23 |
| PreventionGenetics, part of Exact Sciences | Likely benign | no assertion criteria provided | clinical testing | 2019-03-28 |
| Labcorp Genetics (formerly Invitae), Labcorp | Benign | criteria provided, single submitter | clinical testing | 2026-01-25 |
| Blueprint Genetics | Likely benign | criteria provided, single submitter | clinical testing | 2024-11-19 |

## Associated conditions {#conditions}

[autoinflammatory syndrome](https://sugi.bio/atlas/disease/autoinflammatory-syndrome/), [familial hemophagocytic lymphohistiocytosis 3](https://sugi.bio/atlas/disease/familial-hemophagocytic-lymphohistiocytosis-3/).

**Reported phenotype names (ClinVar):** Autoinflammatory syndrome, Familial hemophagocytic lymphohistiocytosis 3, not specified, UNC13D-related disorder, AllHighlyPenetrant, UNC13D-related condition, UNC13D-Related Familial Hemophagocytic Lymphohistiocytosis (UNC13D-fHLH).

## Similar variants {#similar}

Related UNC13D variant pages (same residue, condition, or type): [UNC13D c.1055+1G>A](/variant/unc13d-c-1055-plus-1g-a), [UNC13D c.118-307G>A](/variant/unc13d-c-118-minus-307g-a), [UNC13D c.118-308C>T](/variant/unc13d-c-118-minus-308c-t), [UNC13D c.1389+1G>A](/variant/unc13d-c-1389-plus-1g-a), [UNC13D c.1596+1G>C](/variant/unc13d-c-1596-plus-1g-c), [UNC13D c.1727+1G>A](/variant/unc13d-c-1727-plus-1g-a), [UNC13D c.1848+1G>A](/variant/unc13d-c-1848-plus-1g-a), [UNC13D c.2447+2T>C](/variant/unc13d-c-2447-plus-2t-c).

### 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 719448). 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.*