Is NPC1 p.Pro401Ser (c.1201C>T) pathogenic?

NPC1 p.Pro401Ser (c.1201C>T) is classified Uncertain significance in NPC1 (ClinVar, No assertion criteria, 1 submitter; last evaluated 2025-02-11). AlphaMissense: ambiguous (0.4198); Very rare (popmax 0.0011%, nfe); Associated with Niemann-Pick disease, type C1.

What condition is associated with NPC1 p.Pro401Ser (c.1201C>T)?

NPC1 p.Pro401Ser (c.1201C>T) is associated with Niemann-Pick disease, type C1 (ClinVar).

How common is NPC1 p.Pro401Ser (c.1201C>T) in the general population?

NPC1 p.Pro401Ser (c.1201C>T) is very rare (popmax 0.0011%, nfe) (gnomAD).

How is Niemann-Pick disease type C inherited?

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

What do computational predictors say about NPC1 p.Pro401Ser (c.1201C>T)?

AlphaMissense predicts ambiguous (score 0.4198) — an in-silico prediction, not a clinical call.

NPC1 p.Pro401Ser

c.1201C>T · VCV4058958

Uncertain significance No assertion criteria

Classification

Uncertain significance

ClinVar

Review

No assertion criteria ☆☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.4198 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.0011%, nfe)

Missense predictors

1/2 damaging

REVEL, SaProt · AlphaMissense indeterminate

Conditions

Niemann-Pick disease, type C1

Computational evidence

Protein change
AlphaMissense	0.4198	ambiguous
REVEL	0.776	moderately pathogenic-leaning
SaProt	LLR -9.51	tolerated
⇒ REVEL calls this damaging; SaProt does not; AlphaMissense is indeterminate.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 12	GERP 1.8, phastCons 1
Regional constraint	o/e 0.93	unconstrained · MANE · 54 kb · p 0.0029 · regional, not allelic
Overall
CADD	27.6	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0011% European (non-Finnish) · 13/1,180,022 alleles

Filtering AF 0.000615% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000474%

Overall 0.000805% 13/1,614,160 alleles · very rare exomes 13/1,461,876 · genomes 0/152,284 · 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: NPC1
Protein: p.Pro401Ser
Coding: c.1201C>T
MANE Select: NM_000271
Type: single nucleotide variant
Location: chr18:23556368 (GRCh38)
Gene constraint: LOEUF 0.676 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 85.35 · 20 PDB
Residue 401: a turn; a UniProt-annotated variant site (in npc1)

Full NPC1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Niemann-Pick disease, type C1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Niemann-Pick disease type C (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages
Prevalence: 1-9 / 100 000 (Europe)

Similar variants

NPC1 p.Pro401Thr Pathogenic ★ ⚠ same residue
NPC1 p.Pro401= Likely benign ★ same residue
NPC1 c.1554-1009G>A Pathogenic ★★ same condition
NPC1 c.1757+1G>A Likely pathogenic ★★ same condition
NPC1 c.1947+5G>C Pathogenic/Likely pathogenic ★★ same condition
NPC1 c.2130+1G>A Pathogenic ★★ same condition
NPC1 c.2245+1G>A Pathogenic/Likely pathogenic ★★ same condition
NPC1 c.2246-2A>G 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/npc1-p-pro401ser (accessed [today's date]).

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