# NM_022369.4(STRA6):c.4T>C (p.Ser2Pro)

https://sugi.bio/variant/stra6-p-ser2pro

## Summary

**STRA6 p.Ser2Pro (c.4T>C)** is classified **Uncertain significance** in STRA6 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2018-08-30). AlphaMissense: likely benign (0.0722); Ultra-rare (popmax 0.0952%, amr); Associated with microphthalmia, syndromic 9.

**At a glance:** Uncertain significance · review: Multiple submitters · rsID rs763026708 · 2 submitters · 1 linked condition · AlphaMissense likely benign · ultra-rare (popmax 0.0952%, amr)

## For patients & families {#patients}

This is a change in the STRA6 gene that is currently of uncertain significance — a definitive interpretation has not yet been established, submitted by 2 submitters, and is linked to microphthalmia, syndromic 9.

*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:** [Condition overview & support (NIH GARD)](https://rarediseases.info.nih.gov/diseases/0000713/index) · [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [STRA6](https://sugi.bio/atlas/gene/STRA6/) |
| Protein change (HGVS p.) | p.Ser2Pro |
| Coding change (HGVS c.) | c.4T>C |
| MANE Select transcript | [NM_022369](https://www.ncbi.nlm.nih.gov/nuccore/NM_022369) |
| dbSNP | [rs763026708](https://www.ncbi.nlm.nih.gov/snp/rs763026708/) |
| Variant type | single nucleotide variant |
| Location | chr15:74202264-74202264 (GRCh38) |
| ClinVar | [VCV317119](https://www.ncbi.nlm.nih.gov/clinvar/variation/317119/) |

**All HGVS expressions:** `NC_000015.10:g.74202264A>G`, `NC_000015.9:g.74494605A>G`, `NG_009207.1:g.11767T>C`, `NG_054754.1:g.4560A>G`, `NM_001142617.2:c.4T>C`, `NM_001142618.2:c.4T>C`, `NM_001142619.2:c.4T>C`, `NM_001142620.2:c.4T>C`, `NM_001199040.2:c.115T>C`, `NM_001199041.2:c.49T>C`, `NM_001199042.2:c.121T>C`, `NM_022369.4:c.4T>C`

## Computational & population evidence {#evidence}

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

- AlphaMissense **likely benign** (0.0722)
- REVEL 0.446 (indeterminate)
- SaProt LLR -8.087 (tolerated) — agrees with AlphaMissense
- → **In-silico consensus:** AlphaMissense and SaProt both call this tolerated; REVEL makes no call
- Conservation: phyloP 2.621, GERP -2.46, phastCons 1 — highly conserved (differs from AlphaMissense)
- CADD: **PHRED 19.08**. 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 0.91** across the covering region of the MANE Select transcript (74,180,083–74,202,267), spanning 22,184 bp. Chi-square p 0.0065. 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 **0.0952%** (amr) · FAF95 0.0731% · FAF99 0.0653% · 45/47,248 in the highest group · 45/1,545,084 alleles overall — ultra-rare (popmax 0.0952%, amr).

*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}

**STRA6** population constraint: LOEUF 0.725, pLI 2.3028e-08, missense-Z 1.1287. *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 **2** lies in the 'disordered' region.

AlphaFold model confidence (whole protein): pLDDT 78.18, 38% of residues very-high.

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

*Describes the biological roles of STRA6 (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:** STRA6's established molecular role includes retinol transmembrane transporter activity. p.Ser2Pro falls in the disordered region. In Reactome, STRA6 is annotated in disease pathway(s) including **Defective visual phototransduction due to STRA6 loss of function**.

**Disease mechanism (Reactome):** STRA6 loss or alteration is curated in [Defective visual phototransduction due to STRA6 loss of function](https://reactome.org/content/detail/R-HSA-9918449).

### Pathways affected {#pathways}

STRA6 participates in **2 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Defective visual phototransduction due to STRA6 loss of function](https://reactome.org/content/detail/R-HSA-9918449) | other |
| [The canonical retinoid cycle in rods (twilight vision)](https://reactome.org/content/detail/R-HSA-2453902) | other |

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

**Molecular function:** retinol transmembrane transporter activity.

**Biological process:** blood vessel development, kidney development, pulmonary valve morphogenesis, ventricular septum development, heart development, learning.

## Clinical significance {#significance}

**Uncertain significance** — review status Multiple submitters *(criteria provided, multiple submitters, no conflicts)*, last evaluated 2018-08-30.

**Submitter consensus:** unanimous (2/2 Uncertain significance).

**Submission history:** 2 submissions (2018); classifications have been stable.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Illumina Laboratory Services, Illumina | Uncertain significance | criteria provided, single submitter | clinical testing | 2018-01-13 |
| Baylor Genetics | Uncertain significance | criteria provided, single submitter | clinical testing | 2018-08-30 |

## Associated conditions {#conditions}

[microphthalmia, syndromic 9](https://sugi.bio/atlas/disease/microphthalmia-syndromic-9/).

**Reported phenotype names (ClinVar):** Microphthalmia, syndromic 9, ANOPHTHALMIA, CLINICAL, WITH MILD FACIAL DYSMORPHISM AND VARIABLE MALFORMATIONS OF THE LUNG, HEART, AND DIAPHRAGM, ANOPHTHALMIA/MICROPHTHALMIA AND PULMONARY HYPOPLASIA, Matthew-Wood syndrome, PULMONARY AGENESIS, MICROPHTHALMIA, AND DIAPHRAGMATIC DEFECT, SPEAR SYNDROME.

## Similar variants {#similar}

Related STRA6 variant pages (same residue, condition, or type): [STRA6 c.267-1G>T](/variant/stra6-c-267-minus-1g-t), [STRA6 p.Arg532Ter](/variant/stra6-p-arg532ter), [STRA6 p.Thr644Met](/variant/stra6-p-thr644met), [STRA6 c.*10A>C](/variant/stra6-c-star-10a-c), [STRA6 p.Ala54Ser](/variant/stra6-p-ala54ser), [STRA6 p.Ala557Val](/variant/stra6-p-ala557val), [STRA6 p.Arg467Cys](/variant/stra6-p-arg467cys), [STRA6 p.Arg655Cys](/variant/stra6-p-arg655cys).

### 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 317119). 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.*