Is SAMHD1 p.Arg3Leu (c.8G>T) pathogenic?

SAMHD1 p.Arg3Leu (c.8G>T) is classified Uncertain significance in SAMHD1 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2025-12-13). AlphaMissense: likely benign (0.0882); Very rare (popmax 0.01%, amr); Associated with Aicardi-Goutieres syndrome 5.

What condition is associated with SAMHD1 p.Arg3Leu (c.8G>T)?

SAMHD1 p.Arg3Leu (c.8G>T) is associated with Aicardi-Goutieres syndrome 5, Aicardi-Goutieres syndrome (ClinVar).

How common is SAMHD1 p.Arg3Leu (c.8G>T) in the general population?

SAMHD1 p.Arg3Leu (c.8G>T) is very rare (popmax 0.01%, amr) (gnomAD).

How is Aicardi-Goutières syndrome inherited?

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

What do computational predictors say about SAMHD1 p.Arg3Leu (c.8G>T)?

AlphaMissense predicts likely benign (score 0.0882) — an in-silico prediction, not a clinical call.

SAMHD1 p.Arg3Leu

c.8G>T · rs551472065 · VCV835265

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

AlphaMissense

likely benign

0.0882 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.01%, amr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Aicardi-Goutieres syndrome 5

Computational evidence

Protein change
AlphaMissense	0.0882	likely benign
REVEL	0.221	benign-leaning
SaProt	LLR -6.83	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -1.6	GERP -3.2
Regional constraint	o/e 0.85	unconstrained · MANE · 59 kb · p 1.9e-05 · regional, not allelic
Overall
CADD	7.398	PHRED · no single calibrated threshold — expert panels disagree

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

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.01% Admixed American · 6/60,026 alleles

Filtering AF 0.00428% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00295%

Overall 0.000744% 12/1,613,564 alleles · very rare

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.01%	10,004
Remaining individualsnot grpmax-eligible	0.0016%	62,444
African / African-American	0.00133%	75,042
European (non-Finnish)	0.000339%	294,997

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: SAMHD1
Protein: p.Arg3Leu
Coding: c.8G>T
MANE Select: NM_015474
dbSNP: rs551472065
Type: single nucleotide variant
Location: chr20:36951636 (GRCh38)
Gene constraint: LOEUF 0.889 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 88.45 · 76 PDB
Residue 3: the 'disordered' region

Full SAMHD1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Aicardi-Goutieres syndrome 5 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: Aicardi-Goutieres syndrome

For Aicardi-Goutières syndrome (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive
Onset: Antenatal, Infancy, Neonatal
Prevalence: 1-5 / 10 000 (Europe)

Similar variants

SAMHD1 p.Arg3= Likely benign ★ same residue
SAMHD1 c.1062+1G>T Pathogenic/Likely pathogenic ★★ same condition
SAMHD1 c.1411-2A>G Pathogenic ★★ same condition
SAMHD1 c.509+1G>A Likely pathogenic ★★ same condition
SAMHD1 c.626-1G>C Pathogenic/Likely pathogenic ★★ same condition
SAMHD1 p.Arg106Ter Pathogenic/Likely pathogenic ★★ same condition
SAMHD1 p.Arg134Ter Pathogenic/Likely pathogenic ★★ same condition
SAMHD1 p.Arg143Cys 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/samhd1-p-arg3leu (accessed [today's date]).

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