Is ADA p.Pro297= (c.891G>A) pathogenic?

ADA p.Pro297= (c.891G>A) is classified Likely benign in ADA (ClinVar, Single submitter, 1 submitter; last evaluated 2025-10-27). Ultra-rare (popmax 0.0164%, mid); Associated with severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency.

How common is ADA p.Pro297= (c.891G>A) in the general population?

ADA p.Pro297= (c.891G>A) is ultra-rare (popmax 0.0164%, mid) (gnomAD).

ADA p.Pro297=

Q: What condition is associated with ADA p.Pro297= (c.891G>A)?

ADA p.Pro297= (c.891G>A) is associated with severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency (ClinVar).

Q: How is Severe combined immunodeficiency due to adenosine deaminase deficiency inherited?

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

c.891G>A · rs776360146 · VCV1112497

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0164%, mid)

Conditions

severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency

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 -9.2	GERP -3.4
Overall
CADD	3.495	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0164% Middle Eastern · 1/6,082 alleles

Filtering AF 0.00528% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00381%

Overall 0.00167% 27/1,614,018 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0164%	6,082
African / African-American	0.0107%	9,361
East Asian	0.00668%	14,967
Admixed American	0.00333%	30,002
Remaining individualsnot grpmax-eligible	0.0016%	62,486
South Asian	0.0011%	91,086
European (non-Finnish)	0.000932%	107,276

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: ADA
Protein: p.Pro297=
Coding: c.891G>A
MANE Select: NM_000022
dbSNP: rs776360146
Type: single nucleotide variant
Location: chr20:44621102 (GRCh38)
Gene constraint: LOEUF 1.184 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.81 · 2 PDB
Residue 297: an α-helix; a UniProt-annotated variant site (in adascid)

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

Disease context

severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Severe combined immunodeficiency due to adenosine deaminase deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal
Prevalence: 1-9 / 1 000 000 (Europe)

Similar variants

ADA p.Pro297Leu Likely pathogenic ★★★ ⚠ same residue
ADA p.Pro297Gln Conflicting classifications of pathogenicity ★ ⚠ same residue
ADA c.1078+2T>A Likely pathogenic ★★★ same condition
ADA c.219-2A>G Likely pathogenic ★★★ same condition
ADA c.363-2A>G Likely pathogenic ★★★ same condition
ADA c.606+1G>T Likely pathogenic ★★★ same condition
ADA c.975+1G>A Pathogenic ★★★ same condition
ADA c.976-1G>C 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/ada-p-pro297 (accessed [today's date]).

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