Is ADA p.His15= (c.45T>C) pathogenic?

ADA p.His15= (c.45T>C) is classified Likely benign in ADA (ClinVar, Single submitter, 1 submitter; last evaluated 2023-09-12). Very rare (popmax 0.00534%, afr); 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.His15= (c.45T>C) in the general population?

ADA p.His15= (c.45T>C) is very rare (popmax 0.00534%, afr) (gnomAD).

ADA p.His15=

Q: What condition is associated with ADA p.His15= (c.45T>C)?

ADA p.His15= (c.45T>C) 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.45T>C · rs906269498 · VCV1101044

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00534%, afr)

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 -7.4	GERP -3.7
Overall
CADD	0.089	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00534% African / African-American · 4/74,866 alleles

Filtering AF 0.00175% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00104%

Overall 0.000373% 6/1,608,106 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00534%	18,716
European (non-Finnish)	0.00017%	588,398

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.His15=
Coding: c.45T>C
MANE Select: NM_000022
dbSNP: rs906269498
Type: single nucleotide variant
Location: chr20:44636277 (GRCh38)
Gene constraint: LOEUF 1.184 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.81 · 2 PDB
Residue 15: a UniProt-annotated variant site (in adascid; loss of activity); a binding site

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.His15Asp Pathogenic/Likely pathogenic ★★ same residue
ADA p.His15Leu Likely pathogenic ★★ same residue
ADA p.His15Pro Pathogenic ★ 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

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-his15 (accessed [today's date]).

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