Is ADAR p.Pro663Ser (c.1987C>T) pathogenic?

ADAR p.Pro663Ser (c.1987C>T) is classified Uncertain significance in ADAR (ClinVar, Single submitter, 1 submitter; last evaluated 2021-11-17). AlphaMissense: likely benign (0.1243); Very rare (popmax 0.000593%, nfe); Associated with Aicardi-Goutieres syndrome 6.

What condition is associated with ADAR p.Pro663Ser (c.1987C>T)?

ADAR p.Pro663Ser (c.1987C>T) is associated with Aicardi-Goutieres syndrome 6, dyschromatosis symmetrica hereditaria (ClinVar).

How common is ADAR p.Pro663Ser (c.1987C>T) in the general population?

ADAR p.Pro663Ser (c.1987C>T) is very rare (popmax 0.000593%, nfe) (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 ADAR p.Pro663Ser (c.1987C>T)?

AlphaMissense predicts likely benign (score 0.1243) — an in-silico prediction, not a clinical call.

ADAR p.Pro663Ser

c.1987C>T · rs763748775 · VCV1386881

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.1243 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.000593%, nfe)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Aicardi-Goutieres syndrome 6

Computational evidence

Protein change
AlphaMissense	0.1243	likely benign
REVEL	0.235	benign-leaning
SaProt	LLR -5.35	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 6.3	GERP 0.81, phastCons 1
Regional constraint	o/e 0.74	unconstrained · MANE · 17 kb · p 1.3e-17 · regional, not allelic
Overall
CADD	22.8	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 0.000593% European (non-Finnish) · 7/1,180,022 alleles

Filtering AF 0.000247% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000159%

Overall 0.000558% 9/1,614,028 alleles · very rare exomes 8/1,461,888 · genomes 1/152,140 · joint denominator

Ancestry group	Frequency	1 in
Finnishnot grpmax-eligible	0.00312%	32,013
European (non-Finnish)grpmax	0.000593%	168,575

Finnish shows a higher raw frequency than the grpmax group above it. gnomAD excludes bottlenecked groups — Finnish, Ashkenazi Jewish, Amish and “Remaining individuals” — from grpmax, because founder effects make their frequencies unrepresentative for filtering. The table is sorted by frequency, so an excluded group can sit above the grpmax row.

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: ADAR
Protein: p.Pro663Ser
Coding: c.1987C>T
MANE Select: NM_001111
dbSNP: rs763748775
Type: single nucleotide variant
Location: chr1:154597215 (GRCh38)
Gene constraint: LOEUF 0.449 · pLI 1.00 (gnomAD)
Structure: AlphaFold pLDDT 68.86 · 24 PDB
Residue 663: the drbm 2 domain

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

Disease context

Aicardi-Goutieres syndrome 6 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: dyschromatosis symmetrica hereditaria

For Aicardi-Goutières syndrome (Orphanet):

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

Similar variants

ADAR p.Pro663= Likely benign ★ same residue
ADAR c.2885+1G>A Likely pathogenic ★★ same condition
ADAR p.Arg1078Cys Pathogenic ★★ same condition
ADAR p.Arg1096Ter Pathogenic/Likely pathogenic ★★ same condition
ADAR p.Arg328Ter Pathogenic ★★ same condition
ADAR p.Arg360Ter Pathogenic/Likely pathogenic ★★ same condition
ADAR p.Arg474Ter Pathogenic ★★ same condition
ADAR p.Gln559Ter 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/adar-p-pro663ser (accessed [today's date]).

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