Is NPHP1 p.Arg673Lys (c.2018G>A) pathogenic?

NPHP1 p.Arg673Lys (c.2018G>A) is classified Uncertain significance in NPHP1 (ClinVar, Multiple submitters, 4 submitters; last evaluated 2025-07-31). AlphaMissense: likely benign (0.1201); Very rare (popmax 0.00195%, nfe); Associated with nephronophthisis.

What condition is associated with NPHP1 p.Arg673Lys (c.2018G>A)?

NPHP1 p.Arg673Lys (c.2018G>A) is associated with nephronophthisis, nephronophthisis 1, Senior-Loken syndrome 1 (ClinVar).

How common is NPHP1 p.Arg673Lys (c.2018G>A) in the general population?

NPHP1 p.Arg673Lys (c.2018G>A) is very rare (popmax 0.00195%, nfe) (gnomAD).

How is Nephronophthisis inherited?

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

What do computational predictors say about NPHP1 p.Arg673Lys (c.2018G>A)?

AlphaMissense predicts likely benign (score 0.1201) — an in-silico prediction, not a clinical call.

NPHP1 p.Arg673Lys

c.2018G>A · rs753549193 · VCV968322

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 4 submitters

AlphaMissense

likely benign

0.1201 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00195%, nfe)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

nephronophthisis

Computational evidence

Protein change
AlphaMissense	0.1201	likely benign
REVEL	0.179	moderately benign-leaning
SaProt	LLR -5.77	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 3.8	GERP 1.8, phastCons 0.99
Regional constraint	o/e 0.96	unconstrained · MANE · 81 kb · p 0.26 · regional, not allelic
Overall
CADD	21.7	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.

⚠ Isoform check: AlphaMissense numbered on a different transcript (AM R728K vs ClinVar R673K) — verify the residue.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00195% European (non-Finnish) · 23/1,179,992 alleles

Filtering AF 0.0013% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00108%

Overall 0.00149% 24/1,613,962 alleles · very rare exomes 21/1,461,792 · genomes 3/152,170 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.00195%	51,304
Remaining individualsnot grpmax-eligible	0.0016%	62,482

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: NPHP1
Protein: p.Arg673Lys
Coding: c.2018G>A
MANE Select: NM_001128178
dbSNP: rs753549193
Type: single nucleotide variant
Location: chr2:110123807 (GRCh38)
Gene constraint: LOEUF 0.92 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 76.22 · 2 PDB

Full NPHP1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

nephronophthisis — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: nephronophthisis 1 Senior-Loken syndrome 1 Joubert syndrome with renal defect

For Nephronophthisis (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Adult, Antenatal, Childhood, Infancy, Neonatal
Prevalence: 1-9 / 100 000 (Finland)

Similar variants

NPHP1 p.Arg673Ser Uncertain significance ★ same residue
NPHP1 p.Arg673= Likely benign ★ same residue
NPHP1 p.Arg673Gly Uncertain significance ★ ⚠ same residue
NPHP1 c.1083+1G>A Likely pathogenic ★★ same condition
NPHP1 c.1270-1G>A Pathogenic ★★ same condition
NPHP1 c.1270-2A>G Pathogenic/Likely pathogenic ★★ same condition
NPHP1 c.143+1G>C Likely pathogenic ★★ same condition
NPHP1 c.144-1G>A 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/nphp1-p-arg673lys (accessed [today's date]).

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