Is ALG12 p.Arg270= (c.810C>T) pathogenic?

ALG12 p.Arg270= (c.810C>T) is classified Likely benign in ALG12 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-04-09). Ultra-rare (popmax 0.0165%, mid); Associated with ALG12-congenital disorder of glycosylation.

What condition is associated with ALG12 p.Arg270= (c.810C>T)?

ALG12 p.Arg270= (c.810C>T) is associated with ALG12-congenital disorder of glycosylation (ClinVar).

How common is ALG12 p.Arg270= (c.810C>T) in the general population?

ALG12 p.Arg270= (c.810C>T) is ultra-rare (popmax 0.0165%, mid) (gnomAD).

How is ALG12-CDG inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

ALG12 p.Arg270=

c.810C>T · rs755519504 · VCV2179499

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0165%, mid)

Conditions

ALG12-congenital disorder of glycosylation

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.148	moderately benign-leaning
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -11	GERP -3.2
Overall
CADD	0.517	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0165% Middle Eastern · 1/6,056 alleles

Filtering AF 0.00174% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00104%

Overall 0.00136% 22/1,613,456 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0165%	6,056
Finnishnot grpmax-eligible	0.00631%	15,856
African / African-American	0.00533%	18,758
Remaining individualsnot grpmax-eligible	0.0016%	62,494
European (non-Finnish)	0.00102%	98,331

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: ALG12
Protein: p.Arg270=
Coding: c.810C>T
MANE Select: NM_024105
dbSNP: rs755519504
Type: single nucleotide variant
Location: chr22:49907903 (GRCh38)
Gene constraint: LOEUF 0.965 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 93.26

Full ALG12 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

ALG12-congenital disorder of glycosylation — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For ALG12-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

ALG12 p.Arg270Cys Uncertain significance ★★ ⚠ same residue
ALG12 p.Arg270His Uncertain significance ★★ ⚠ same residue
ALG12 p.Arg270Gly Uncertain significance ★ ⚠ same residue
ALG12 p.Arg270Leu Uncertain significance ★ ⚠ same residue
ALG12 c.295+1G>A Pathogenic/Likely pathogenic ★★ same condition
ALG12 c.768+1G>A Likely pathogenic ★★ same condition
ALG12 p.Arg146Gln Pathogenic/Likely pathogenic ★★ same condition
ALG12 p.Arg202Ter Pathogenic/Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/alg12-p-arg270 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown