mitochondrial complex III deficiency nuclear type 3

disease

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Also known as MC3DN3mitochondrial complex III deficiency caused by mutation in UQCRBmitochondrial complex III deficiency, nuclear type 3UQCRB mitochondrial complex III deficiency

Summary

mitochondrial complex III deficiency nuclear type 3 (MONDO:0014064) is a disease caused by UQCRB (GenCC Strong), with 1 cohort gene.

At a glance

Causal gene: UQCRB (GenCC Strong)
Cohort genes: 1
ClinVar variants: 7

Clinical features

No curated clinical features (Orphanet) for this disease.

Identifiers

Disease identifiers

Field	Value
Canonical name	mitochondrial complex III deficiency nuclear type 3
Mondo ID	MONDO:0014064
OMIM	615158
DOID	DOID:0080112
UMLS	C3554606
MedGen	767520
GARD	0015911
Is cancer (heuristic)	no

Also known as: MC3DN3 · mitochondrial complex III deficiency caused by mutation in UQCRB · mitochondrial complex III deficiency, nuclear type 3 · UQCRB mitochondrial complex III deficiency

Data availability: 7 ClinVar variants · 4 GenCC gene-disease records.

Disease family

Classification path: disease › human disease › disease by developmental or physiological process › metabolic disease › developmental anomaly of metabolic origin › inborn mitochondrial metabolism disorder › mitochondrial oxidative phosphorylation disorder › mitochondrial respiratory chain complex deficiency › mitochondrial complex III deficiency › mitochondrial complex III deficiency, nuclear type › mitochondrial complex III deficiency nuclear type 3

Genetics & variants

GWAS landscape

No GWAS associations recorded — common-variant (GWAS) studies don’t cover this disease (typical for Mendelian / rare diseases). See the curated gene cohort and Mendelian overlap below.

Variant details and genetic-evidence tiers

ClinVar germline variants

7 retrieved; paginated sample, class counts are floors:

2 conflicting classifications of pathogenicity, 2 uncertain significance, 1 benign, 1 likely pathogenic, 1 likely benign

ClinVar	Variant (HGVS)	Gene	Classification	Review
444760	NM_006294.5(UQCRB):c.310G>T (p.Glu104Ter)	UQCRB	Likely pathogenic	criteria provided, multiple submitters, no conflicts
286054	NM_006294.5(UQCRB):c.306_309del (p.Arg105fs)	UQCRB	Conflicting classifications of pathogenicity	criteria provided, conflicting classifications
288054	NM_006294.5(UQCRB):c.200T>A (p.Leu67Gln)	UQCRB	Conflicting classifications of pathogenicity	criteria provided, conflicting classifications
3376397	NM_006294.5(UQCRB):c.305G>A (p.Arg102Lys)	UQCRB	Uncertain significance	criteria provided, multiple submitters, no conflicts
3813756	NM_006294.5(UQCRB):c.101G>A (p.Arg34Gln)	UQCRB	Uncertain significance	criteria provided, multiple submitters, no conflicts
1246446	NM_006294.5(UQCRB):c.258+282C>T	UQCRB	Benign	criteria provided, multiple submitters, no conflicts
811923	NM_006294.5(UQCRB):c.258+268G>A	UQCRB	Likely benign	criteria provided, multiple submitters, no conflicts

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 5 · Orphanet: 1 · OMIM-shared: 0 · Dual-evidence (GWAS+Mendelian): 0

GenCC gene–disease validity (cohort genes)

the Disease column is the GenCC-asserted condition — a cohort gene’s strongest validity may be for a related predisposition syndrome.

Gene	Classification	Inheritance	Disease	Records
UQCRB	Strong	Autosomal recessive	mitochondrial complex III deficiency nuclear type 3	5

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
UQCRB	Orphanet:1460	Isolated complex III deficiency

Cohort genes → proteins

1 cohort genes, 1 distinct canonical proteins.

Evidence partition

Subset	Genes
multi_evidence	1

Cohort genes (full)

Symbol	HGNC	Ensembl	UniProt	Name	Evidence
UQCRB	HGNC:12582	ENSG00000156467	P14927	Cytochrome b-c1 complex subunit 7	gencc,clinvar

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
UQCRB	Cytochrome b-c1 complex subunit 7	Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation.

Protein-family classification

Druggable: 1 · Difficult: 0 · Unknown: 0 · Druggable fraction: 1.0

Family distribution

Cohort families vs a genome-wide background (hypergeometric, BH-FDR; fold = observed/expected). Counts kept; sorted by enrichment, so the catch-all Other/Unknown bucket no longer leads.

Family	Genes	Fold	FDR
Enzyme (other)	1	12.0×	0.083

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
UQCRB	Enzyme (other)	yes	7.1.1.8	QCR7, QCR7_sf

Expression context

Cohort genes with no expression data: 0.

1 cohort gene are a single-cell marker in ≥1 SCXA experiment.

Breadth distribution (Bgee present_calls)

Bucket	Genes
narrow (1-5 tissues)	0
moderate (6-20)	0
broad (>20)	1
unknown	0

Top tissues across cohort

Tissue	Cohort genes
heart right ventricle	1
renal medulla	1
vena cava	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
UQCRB	304	ubiquitous	marker	heart right ventricle, vena cava, renal medulla

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
UQCRB	2,538

Structural data

PDB: 1 · AlphaFold-only: 0 · No structure: 0

Cohort genes with PDB structures (top 30)

Symbol	UniProt	PDB entries
UQCRB	P14927	5

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 2. Enrichment computed across 1 evidence-associated genes (1 with Reactome annotation).

Pathways by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

Pathway	Cohort genes	Fold	FDR	Sample cohort genes
Complex III assembly	1	439.2×	0.005	UQCRB
Respiratory electron transport	1	95.2×	0.011	UQCRB

GO biological processes by enrichment

GO term	Cohort genes	Fold	FDR	Sample cohort genes
oxidative phosphorylation	1	1404.3×	0.002	UQCRB
mitochondrial electron transport, ubiquinol to cytochrome c	1	1296.3×	0.002	UQCRB
cellular respiration	1	432.1×	0.003	UQCRB
aerobic respiration	1	247.8×	0.004	UQCRB

Therapeutics

Drug target analysis

Approved (phase 4): 0 · Phase ≥3: 0 · Phased (≥1): 0 · Undrugged: 1

Druggability breadth: 1 of 1 evidence-associated genes (100%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
UQCRB	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 1.

Cohort genes with ChEMBL bioactivity (full, sorted by assay count)

Symbol	Assays	Type breakdown
UQCRB	9	Binding:9

Cohort enzymes (BRENDA EC)

Symbol	EC numbers	Names
UQCRB	7.1.1.8	quinol-cytochrome-c reductase

Pharmacogenomics

Cohort genes with a PharmGKB record: 1; with CPIC/DPWG dosing guidelines: 0.

No cohort gene has a CPIC/DPWG genotype-guided dosing guideline (PharmGKB).

Chemical tractability of cohort targets

0 approved/phased compounds have measured bioactivity against a cohort gene (and aren’t yet in disease-level trials). This is a research / tractability signal, NOT a therapeutic recommendation — a bioactivity row often reflects off-target or screening binding (e.g. promiscuous kinase inhibitors against a cohort kinase), implying no disease mechanism.

Druggability pyramid

Cohort genes binned by druggability tier (high → low):

Tier	Definition	Genes	Symbols
A	Approved (phase 4 drug)	0
B	Phased (≥1) drug, not yet approved	0
C	Druggable family + PDB, no drug	1	UQCRB
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	0

Undrugged target profiles

1 cohort genes are undrugged. Ranked by ‘starting-point quality’ (assay depth + drugged-partner adjacency).

Symbol	ChEMBL assays	Drugged partners (top 3)
UQCRB	9	—

Clinical trials & evidence

Clinical trials

Clinical trials: 0.

Cohort genes: UQCRB