Is FDPS p.Asn221Lys (c.663C>A) pathogenic?

FDPS p.Asn221Lys (c.663C>A) is classified Uncertain significance in FDPS (ClinVar, Single submitter, 1 submitter; last evaluated 2025-11-03). AlphaMissense: likely benign (0.3121); Ultra-rare (popmax 0.0187%, sas).

How common is FDPS p.Asn221Lys (c.663C>A) in the general population?

FDPS p.Asn221Lys (c.663C>A) is ultra-rare (popmax 0.0187%, sas) (gnomAD).

What do computational predictors say about FDPS p.Asn221Lys (c.663C>A)?

AlphaMissense predicts likely benign (score 0.3121) — an in-silico prediction, not a clinical call.

FDPS p.Asn221Lys

c.663C>A · VCV4668158

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.3121 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0187%, sas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.3121	likely benign
REVEL	0.105	moderately benign-leaning
SaProt	LLR -8.96	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 1.8	GERP 1.1, phastCons 1
Regional constraint	o/e 0.79	unconstrained · MANE · 11 kb · p 1.1e-06 · regional, not allelic
Overall
CADD	22.2	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 0.0187% South Asian · 17/91,090 alleles

Filtering AF 0.0118% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00976%

Overall 0.00236% 38/1,612,842 alleles · ultra-rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0187%	5,358
Finnishnot grpmax-eligible	0.0175%	5,699
Admixed American	0.00833%	12,005
Remaining individualsnot grpmax-eligible	0.0064%	15,624
Ashkenazi Jewishnot grpmax-eligible	0.00338%	29,608

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: FDPS
Protein: p.Asn221Lys
Coding: c.663C>A
MANE Select: NM_002004
Type: single nucleotide variant
Location: chr1:155318270 (GRCh38)
Gene constraint: LOEUF 0.744 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 85.27 · 92 PDB
Residue 221: an α-helix

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

Similar variants

FDPS c.684+2T>G Likely pathogenic ★ same type
FDPS p.Ala119Val Uncertain significance ★ ⚠ same type
FDPS p.Arg110Gly Uncertain significance ★ ⚠ same type
FDPS p.Arg110Trp Uncertain significance ★ ⚠ same type
FDPS p.Arg214Gln Uncertain significance ★ ⚠ same type
FDPS p.Arg23Gln Uncertain significance ★ ⚠ same type
FDPS p.Arg23Trp Uncertain significance ★ ⚠ same type
FDPS p.Arg25Lys Uncertain significance ★ ⚠ same type

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/fdps-p-asn221lys (accessed [today's date]).

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