Is PSAP p.Ser29Trp (c.86C>G) pathogenic?

PSAP p.Ser29Trp (c.86C>G) is classified Uncertain significance in PSAP (ClinVar, Single submitter, 1 submitter; last evaluated 2024-02-17). AlphaMissense: ambiguous (0.5038); Very rare (popmax 0.000254%, nfe); Associated with metachromatic leukodystrophy due to saposin B deficiency.

What condition is associated with PSAP p.Ser29Trp (c.86C>G)?

PSAP p.Ser29Trp (c.86C>G) is associated with metachromatic leukodystrophy due to saposin B deficiency (ClinVar).

How common is PSAP p.Ser29Trp (c.86C>G) in the general population?

PSAP p.Ser29Trp (c.86C>G) is very rare (popmax 0.000254%, nfe) (gnomAD).

How is Metachromatic leukodystrophy inherited?

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

What do computational predictors say about PSAP p.Ser29Trp (c.86C>G)?

AlphaMissense predicts ambiguous (score 0.5038) — an in-silico prediction, not a clinical call.

PSAP p.Ser29Trp

c.86C>G · rs758565002 · VCV1989307

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.5038 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.000254%, nfe)

Conditions

metachromatic leukodystrophy due to saposin B deficiency

Computational evidence

Protein change
AlphaMissense	0.5038	ambiguous
REVEL	0.557	indeterminate
SaProt	LLR -12.95	damaging
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 1.8, phastCons 1
Overall
CADD	33.0	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 0.000254% European (non-Finnish) · 3/1,179,952 alleles

Filtering AF 6.8e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 1.9e-05%

Overall 0.000205% 3/1,461,670 alleles · very rare

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: PSAP
Protein: p.Ser29Trp
Coding: c.86C>G
MANE Select: NM_002778
dbSNP: rs758565002
Type: single nucleotide variant
Location: chr10:71834460 (GRCh38)
Gene constraint: LOEUF 0.507 · pLI 0.95 (gnomAD)
Structure: AlphaFold pLDDT 73.90 · 21 PDB
Residue 29: the saposin a-type 1 domain

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

Disease context

metachromatic leukodystrophy due to saposin B deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Metachromatic leukodystrophy (Orphanet):

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

Similar variants

PSAP p.Ser29Leu Uncertain significance ★★ ⚠ same residue
PSAP p.Ser29= Likely benign ★ same residue
PSAP c.1005+1G>A Pathogenic/Likely pathogenic ★★ same condition
PSAP c.375+1G>T Likely pathogenic ★★ same condition
PSAP c.576+1G>A Likely pathogenic ★★ same condition
PSAP c.577-1G>T Pathogenic ★★ same condition
PSAP c.721-1G>A Likely pathogenic ★★ same condition
PSAP p.Asn215His 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/psap-p-ser29trp (accessed [today's date]).

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