# NM_024079.5(ALG8):c.469A>G (p.Ile157Val)

https://sugi.bio/variant/alg8-p-ile157val

## Summary

**ALG8 p.Ile157Val (c.469A>G)** is classified **Uncertain significance** in ALG8 (ClinVar, Single submitter, 1 submitter; last evaluated 2020-02-14). AlphaMissense: likely benign (0.0775); Very rare (popmax 8.48e-05%, nfe).

**At a glance:** Uncertain significance · review: Single submitter · rsID rs2136919576 · 1 submitter · AlphaMissense likely benign · very rare (popmax 8.48e-05%, nfe)

## For patients & families {#patients}

This is a change in the ALG8 gene that is currently of uncertain significance — a definitive interpretation has not yet been established, submitted by 1 submitter.

*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 | [ALG8](https://sugi.bio/atlas/gene/ALG8/) |
| Protein change (HGVS p.) | p.Ile157Val |
| Coding change (HGVS c.) | c.469A>G |
| MANE Select transcript | [NM_024079](https://www.ncbi.nlm.nih.gov/nuccore/NM_024079) |
| dbSNP | [rs2136919576](https://www.ncbi.nlm.nih.gov/snp/rs2136919576/) |
| Variant type | single nucleotide variant |
| Location | chr11:78121074-78121074 (GRCh38) |
| ClinVar | [VCV1690806](https://www.ncbi.nlm.nih.gov/clinvar/variation/1690806/) |

**All HGVS expressions:** `NC_000011.10:g.78121074T>C`, `NC_000011.9:g.77832120T>C`, `NG_008926.1:g.23580A>G`, `NM_001007027.3:c.469A>G`, `NM_024079.5:c.469A>G`

## Computational & population evidence {#evidence}

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

- AlphaMissense **likely benign** (0.0775)
- REVEL 0.521 (indeterminate)
- SaProt LLR -8.311 (tolerated) — agrees with AlphaMissense
- → **In-silico consensus:** AlphaMissense and SaProt both call this tolerated; REVEL makes no call
- Conservation: phyloP 1.457, GERP 1.16, phastCons 0.999 — weakly conserved position
- CADD: **PHRED 18.49**. 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.*
- Regional missense constraint: **o/e 0.94** across the covering region of the MANE Select transcript (78,100,967–78,139,588), spanning 38,621 bp. Chi-square p 0.14. 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 **8.48e-05%** (nfe) · 1/1,179,226 in the highest group · 1/1,460,774 alleles overall — very rare (popmax 8.48e-05%, nfe).

*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}

**ALG8** population constraint: LOEUF 0.909, pLI 1.8738e-10, missense-Z 0.42414. *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):

- **autosomal dominant polycystic kidney disease** — Definitive (AD)

## Protein context {#protein}


AlphaFold model confidence (whole protein): pLDDT 92.07, 82% of residues very-high.

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

*Describes the biological roles of ALG8 (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:** ALG8's established molecular role includes dolichyl pyrophosphate Glc1Man9GlcNAc2 alpha-1,3-glucosyltransferase activity. In Reactome, ALG8 is annotated in disease pathway(s) including **Defective ALG8 causes CDG-1h**.

**Disease mechanism (Reactome):** ALG8 loss or alteration is curated in [Defective ALG8 causes CDG-1h](https://reactome.org/content/detail/R-HSA-4724325).

### Pathways affected {#pathways}

ALG8 participates in **2 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Defective ALG8 causes CDG-1h](https://reactome.org/content/detail/R-HSA-4724325) | curated |
| [Biosynthesis of the N-glycan precursor (dolichol lipid-linked oligosaccharide, LLO) and transfer to a nascent protein](https://reactome.org/content/detail/R-HSA-446193) | curated |

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

**Molecular function:** dolichyl pyrophosphate Glc1Man9GlcNAc2 alpha-1,3-glucosyltransferase activity.

**Biological process:** protein N-linked glycosylation, dolichol-linked oligosaccharide biosynthetic process.

## Clinical significance {#significance}

**Uncertain significance** — review status Single submitter *(criteria provided, single submitter)*, last evaluated 2020-02-14.

**Submitter consensus:** unanimous (1/1 Uncertain significance).

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein | Uncertain significance | criteria provided, single submitter | clinical testing | 2020-02-14 |

**Reported phenotype names (ClinVar):** See cases.

## Similar variants {#similar}

Related ALG8 variant pages (same residue, condition, or type): [ALG8 c.368+2T>G](/variant/alg8-c-368-plus-2t-g), [ALG8 c.674-2A>G](/variant/alg8-c-674-minus-2a-g), [ALG8 c.777+1G>A](/variant/alg8-c-777-plus-1g-a), [ALG8 c.95+1G>A](/variant/alg8-c-95-plus-1g-a), [ALG8 p.Arg179Ter](/variant/alg8-p-arg179ter), [ALG8 p.Arg229Ter](/variant/alg8-p-arg229ter), [ALG8 p.Arg268Ter](/variant/alg8-p-arg268ter), [ALG8 p.Arg364Ter](/variant/alg8-p-arg364ter).

### 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 1690806). 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.*