Is NAGLU p.Glu421= (c.1263G>A) pathogenic?

NAGLU p.Glu421= (c.1263G>A) is classified Likely benign in NAGLU (ClinVar, Single submitter, 1 submitter; last evaluated 2024-01-12). Very rare (popmax 0.00223%, eas); Associated with mucopolysaccharidosis type 3B.

What condition is associated with NAGLU p.Glu421= (c.1263G>A)?

NAGLU p.Glu421= (c.1263G>A) is associated with mucopolysaccharidosis type 3B, Charcot-Marie-Tooth disease axonal type 2V (ClinVar).

How common is NAGLU p.Glu421= (c.1263G>A) in the general population?

NAGLU p.Glu421= (c.1263G>A) is very rare (popmax 0.00223%, eas) (gnomAD).

How is Mucopolysaccharidosis type 3 inherited?

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

NAGLU p.Glu421=

c.1263G>A · rs2510659200 · VCV2922159

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Conditions

mucopolysaccharidosis type 3B

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 1.7	GERP -1, phastCons 1
Overall
CADD	5.738	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00223% East Asian · 1/44,888 alleles

Overall 6.2e-05% 1/1,614,056 alleles · very rare exomes 1/1,461,678 · genomes 0/152,378 · joint denominator

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: NAGLU
Protein: p.Glu421=
Coding: c.1263G>A
MANE Select: NM_000263
dbSNP: rs2510659200
Type: single nucleotide variant
Location: chr17:42543269 (GRCh38)
Gene constraint: LOEUF 1.029 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 97.19 · 1 PDB
Residue 421: an α-helix; a UniProt-annotated variant site (in mps3b)

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

Disease context

mucopolysaccharidosis type 3B — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: Charcot-Marie-Tooth disease axonal type 2V

For Mucopolysaccharidosis type 3 (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood
Prevalence: 1-9 / 1 000 000 (Brazil)

Similar variants

NAGLU c.1021+1G>A Likely pathogenic ★★ same condition
NAGLU c.1022-2A>G Pathogenic/Likely pathogenic ★★ same condition
NAGLU c.383+1G>T Pathogenic/Likely pathogenic ★★ same condition
NAGLU c.384-1G>A Pathogenic ★★ same condition
NAGLU c.531+1G>A Pathogenic ★★ same condition
NAGLU c.531+1G>C Pathogenic ★★ same condition
NAGLU c.678+1G>A Pathogenic/Likely pathogenic ★★ same condition
NAGLU p.Arg130Cys 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/naglu-p-glu421 (accessed [today's date]).

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