Is UNG p.Ala27= (c.81C>A) pathogenic?

UNG p.Ala27= (c.81C>A) is classified Conflicting classifications of pathogenicity in UNG (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2024-02-17). Ultra-rare (popmax 0.0429%, eas); Associated with hyper-IgM syndrome type 5.

What condition is associated with UNG p.Ala27= (c.81C>A)?

UNG p.Ala27= (c.81C>A) is associated with hyper-IgM syndrome type 5 (ClinVar).

How common is UNG p.Ala27= (c.81C>A) in the general population?

UNG p.Ala27= (c.81C>A) is ultra-rare (popmax 0.0429%, eas) (gnomAD).

UNG p.Ala27=

c.81C>A · rs761928219 · VCV306966

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0429%, eas)

Conditions

hyper-IgM syndrome type 5

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -3.9	GERP -8.5
Overall
CADD	4.707	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0429% East Asian · 18/41,934 alleles

Filtering AF 0.0277% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0229%

Overall 0.0021% 33/1,570,738 alleles · ultra-rare exomes 27/1,418,356 · genomes 6/152,382 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.0429%	2,330
Remaining individualsnot grpmax-eligible	0.00494%	20,248
Admixed American	0.00185%	54,038
European (non-Finnish)	0.00095%	105,269

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: UNG
Protein: p.Ala27=
Coding: c.81C>A
MANE Select: NM_080911
dbSNP: rs761928219
Type: single nucleotide variant
Location: chr12:109097760 (GRCh38)
Gene constraint: LOEUF 1.22 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 86.52 · 24 PDB
Residue 27: the 'disordered' region; the 'mitochondrial localization signal' region

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

Disease context

hyper-IgM syndrome type 5 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

UNG c.623-9T>A Uncertain significance ★★ same condition
UNG c.801+5G>A Uncertain significance ★★ same condition
UNG p.Ala21Thr Uncertain significance ★★ ⚠ same condition
UNG p.Ala87Val Uncertain significance ★★ ⚠ same condition
UNG p.Arg122Ser Uncertain significance ★★ ⚠ same condition
UNG p.Arg269Trp Uncertain significance ★★ ⚠ same condition
UNG p.Asn77Lys Uncertain significance ★★ ⚠ same condition
UNG p.Gln133His Uncertain significance ★★ ⚠ 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/ung-p-ala27 (accessed [today's date]).

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