SUOX

Chr 12AR

sulfite oxidase

NCBI Gene: 6821ENSG00000139531UniProt: P51687

Sulfite oxidase is a homodimeric protein localized to the intermembrane space of mitochondria. Each subunit contains a heme domain and a molybdopterin-binding domain. The enzyme catalyzes the oxidation of sulfite to sulfate, the final reaction in the oxidative degradation of the sulfur amino acids cysteine and methionine. Sulfite oxidase deficiency results in neurological abnormalities which are often fatal at an early age. Alternative splicing results in multiple transcript variants encoding identical proteins. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Sulfite oxidase deficiencyMIM #272300
AR
525
ClinVar variants
88
Pathogenic / LP
0.00
pLI score
0
Active trials
Clinical Summary— SUOX
🧬
Gene-Disease Validity (ClinGen)
isolated sulfite oxidase deficiency · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
88 Pathogenic / Likely Pathogenic· 208 VUS of 525 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
1.08LOEUF
pLI 0.000
Z-score 1.31
OE 0.67 (0.43–1.08)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
0.45Z-score
OE missense 0.93 (0.84–1.02)
289 obs / 311.3 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.67 (0.43–1.08)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.93 (0.84–1.02)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.90
0≤1.21.6
LoF obs/exp: 12 / 18.0Missense obs/exp: 289 / 311.3Syn Z: 0.85

ClinVar Variant Classifications

525 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic63
Likely Pathogenic25
VUS208
Likely Benign199
Benign6
Conflicting24
63
Pathogenic
25
Likely Pathogenic
208
VUS
199
Likely Benign
6
Benign
24
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
30
1
32
0
63
Likely Pathogenic
7
12
6
0
25
VUS
1
182
25
0
208
Likely Benign
0
8
30
161
199
Benign
0
1
3
2
6
Conflicting
—24
Total3820496163525

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

SUOX · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Gene2Phenotype Curations

SUOX-related sulfite oxidase deficiency

definitive
ARLoss Of FunctionAbsent Gene Product
Dev. DisordersEye
G2P ↗

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM
SULFITE OXIDASE; SUOX
MIM #606887 · *

Sulfite oxidase deficiency

MIM #272300

Molecular basis of disorder known

Autosomal recessive
📖
GeneReview available — SUOX
Authoritative clinical overview · NCBI Bookshelf · Recommended first read
Open GeneReview ↗
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Emerging roles of hydrogen sulfide-metabolizing enzymes in cancer.
Dawoud A et al.·Redox Rep
2024Review
Isolated sulfite oxidase deficiency.
Claerhout H et al.·J Inherit Metab Dis
2018Review
[Analysis of SUOX gene variants and clinical features in a child with Isolated sulfite oxidase deficiency].
Wang Y et al.·Zhonghua Yi Xue Yi Chuan Xue Za Zhi
2023Case report
Mutation analysis of SUOX in isolated sulfite oxidase deficiency with ectopia lentis as the presenting feature: insights into genotype-phenotype correlation.
Li JT et al.·Orphanet J Rare Dis
2022Case report
Genetics of polycystic ovary syndrome.
Welt CK et al.·Semin Reprod Med
2014Review
Machine learning-based identification and characterization of 15 novel pathogenic SUOX missense mutations.
Kaczmarek AT et al.·Mol Genet Metab
2021
Isolated sulfite oxidase deficiency: a founder mutation.
Mhanni AA et al.·Cold Spring Harb Mol Case Stud
2020
Identification of a novel SUOX pathogenic variants as the cause of isolated sulfite oxidase deficiency in a Chinese pedigree.
Du P et al.·Mol Genet Genomic Med
2021Case report
Prevalence and clinical significance of autoantibodies to sulphite oxidase and glycogen phosphorylase in Chinese primary biliary cholangitis patients.
Jawed R·Mol Biol Rep
2025Cohort
Ultra-orphan diseases: A cross-sectional quantitative analysis of the natural history of isolated sulfite oxidase deficiency.
Göde L et al.·PLoS One
2025Natural history
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools