Is SAMHD1 p.Arg551Pro (c.1652G>C) pathogenic?

SAMHD1 p.Arg551Pro (c.1652G>C) is classified Uncertain significance in SAMHD1 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-01-11). AlphaMissense: likely pathogenic (0.996); Absent from gnomAD v4.1; Associated with Aicardi-Goutieres syndrome 5.

What condition is associated with SAMHD1 p.Arg551Pro (c.1652G>C)?

SAMHD1 p.Arg551Pro (c.1652G>C) is associated with Aicardi-Goutieres syndrome 5 (ClinVar).

How common is SAMHD1 p.Arg551Pro (c.1652G>C) in the general population?

SAMHD1 p.Arg551Pro (c.1652G>C) is absent from gnomAD v4.1 (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.Arg551Pro (c.1652G>C)?

AlphaMissense predicts likely pathogenic (score 0.996) — an in-silico prediction, not a clinical call.

SAMHD1 p.Arg551Pro

c.1652G>C · VCV3775957

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely pathogenic

0.996 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Aicardi-Goutieres syndrome 5

Computational evidence

Protein change
AlphaMissense	0.996	likely pathogenic · top 1% in SAMHD1
REVEL	0.886	moderately pathogenic-leaning
SaProt	LLR -15.85	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.5	GERP 1.3, phastCons 1
Regional constraint	o/e 0.85	unconstrained · MANE · 59 kb · p 1.9e-05 · regional, not allelic
Overall
CADD	24.7	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean damaging — 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

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: SAMHD1
Protein: p.Arg551Pro
Coding: c.1652G>C
MANE Select: NM_015474
Type: single nucleotide variant
Location: chr20:36897916 (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 551: a UniProt-annotated variant site (in ags5; does not affect dntp regulation, while affecting ability to promote dna end resection at stalled replication forks); a β-strand

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

For Aicardi-Goutières syndrome (Orphanet):

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

Similar variants

SAMHD1 p.Arg551Ter Pathogenic/Likely pathogenic ★★ same residue
SAMHD1 p.Arg551Gln Uncertain significance ★ ⚠ 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

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-arg551pro (accessed [today's date]).

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