Is MOCS2 p.Val87= (c.261C>T) pathogenic?

MOCS2 p.Val87= (c.261C>T) is classified Conflicting classifications of pathogenicity in MOCS2 (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2025-04-29). Ultra-rare (popmax 0.0107%, afr); Associated with sulfite oxidase deficiency due to molybdenum cofactor deficiency type B1.

What condition is associated with MOCS2 p.Val87= (c.261C>T)?

MOCS2 p.Val87= (c.261C>T) is associated with sulfite oxidase deficiency due to molybdenum cofactor deficiency type B1 (ClinVar).

How common is MOCS2 p.Val87= (c.261C>T) in the general population?

MOCS2 p.Val87= (c.261C>T) is ultra-rare (popmax 0.0107%, afr) (gnomAD).

MOCS2 p.Val87=

c.261C>T · rs777565219 · VCV353877

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0107%, afr)

Conditions

sulfite oxidase deficiency due to molybdenum cofactor deficiency type B1

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 2	GERP 1.6, phastCons 0.98
Overall
CADD	8.245	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0107% African / African-American · 8/74,688 alleles

Filtering AF 0.00529% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00382%

Overall 0.00087% 14/1,609,758 alleles · ultra-rare exomes 9/1,457,890 · genomes 5/151,868 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.0107%	9,336
Finnishnot grpmax-eligible	0.00315%	31,722
Remaining individualsnot grpmax-eligible	0.0016%	62,342
European (non-Finnish)	0.000255%	392,326

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: MOCS2
Protein: p.Val87=
Coding: c.261C>T
MANE Select: NM_004531
dbSNP: rs777565219
Type: single nucleotide variant
Location: chr5:53101475 (GRCh38)
Gene constraint: LOEUF 1.066 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 84.07 · 2 PDB
Residue 87: a β-strand; a UniProt-annotated variant site (in mocodb1)

Full MOCS2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

sulfite oxidase deficiency due to molybdenum cofactor deficiency type B1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

MOCS2 c.377+1G>A Pathogenic/Likely pathogenic ★★ same condition
MOCS2 p.Gln30Ter Pathogenic/Likely pathogenic ★★ same condition
MOCS2 p.Glu40Ter Pathogenic/Likely pathogenic ★★ same condition
MOCS2 p.Ter189Tyr Pathogenic/Likely pathogenic ★★ same condition
MOCS2 p.Trp38Ter Likely pathogenic ★★ same condition
MOCS2 p.Tyr11Ter Pathogenic ★★ same condition
MOCS2 c.*837T>C Uncertain significance ★★ same condition
MOCS2 p.Ala58Thr Uncertain significance ★★ 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/mocs2-p-val87 (accessed [today's date]).

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