mitochondrial complex III deficiency nuclear type 9

disease

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Also known as MC3DN9mitochondrial complex III deficiency caused by mutation in UQCC3mitochondrial complex III deficiency, nuclear type 9UQCC3 mitochondrial complex III deficiency

Summary

mitochondrial complex III deficiency nuclear type 9 (MONDO:0014496) is a disease with 2 cohort genes.

At a glance

Cohort genes: 2
ClinVar variants: 2

Clinical features

No curated clinical features (Orphanet) for this disease.

Identifiers

Disease identifiers

Field	Value
Canonical name	mitochondrial complex III deficiency nuclear type 9
Mondo ID	MONDO:0014496
OMIM	616111
DOID	DOID:0080118
UMLS	C4015253
MedGen	863690
GARD	0016060
Is cancer (heuristic)	no

Also known as: MC3DN9 · mitochondrial complex III deficiency caused by mutation in UQCC3 · mitochondrial complex III deficiency, nuclear type 9 · UQCC3 mitochondrial complex III deficiency

Data availability: 2 ClinVar variants · 1 GenCC gene-disease record.

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 9

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

2 retrieved; paginated sample, class counts are floors:

1 pathogenic, 1 benign

ClinVar	Variant (HGVS)	Gene	Classification	Review
161120	NM_001085372.3(UQCC3):c.59T>A (p.Val20Glu)	LBHD1	Pathogenic	no assertion criteria provided
380147	NM_001085372.3(UQCC3):c.265G>A (p.Gly89Ser)	LBHD1	Benign	criteria provided, multiple submitters, no conflicts

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 2 · 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
UQCC3	Moderate	Autosomal recessive	mitochondrial complex III deficiency nuclear type 9	2

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
UQCC3	Orphanet:1460	Isolated complex III deficiency

Cohort genes → proteins

2 cohort genes, 2 distinct canonical proteins.

Evidence partition

Subset	Genes
multi_evidence	2

Cohort genes (full)

Symbol	HGNC	Ensembl	UniProt	Name	Evidence
UQCC3	HGNC:34399	ENSG00000204922	Q6UW78	Ubiquinol-cytochrome-c reductase complex assembly factor 3	gencc
LBHD1	HGNC:28351	ENSG00000162194	Q9BQE6	LBH domain-containing protein 1	clinvar

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
UQCC3	Ubiquinol-cytochrome-c reductase complex assembly factor 3	Required for the assembly of the ubiquinol-cytochrome c reductase complex (mitochondrial respiratory chain complex III or cytochrome b-c1 complex), mediating cytochrome b recruitment and probably stabilization within the complex.

Protein-family classification

Druggable: 0 · Difficult: 0 · Unknown: 2 · Druggable fraction: 0.0

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
Other/Unknown	2	1.8×	0.312

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
UQCC3	Other/Unknown	no		UQCC3
LBHD1	Other/Unknown	no		LBH_dom, LBH_dom_prot

Expression context

Cohort genes with no expression data: 0.

2 cohort genes 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)	2
unknown	0

Top tissues across cohort

Tissue	Cohort genes
endothelial cell	1
mucosa of transverse colon	1
upper arm skin	1
granulocyte	1
right adrenal gland	1
right adrenal gland cortex	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
UQCC3	246	ubiquitous	marker	endothelial cell, upper arm skin, mucosa of transverse colon
LBHD1	133	ubiquitous	marker	granulocyte, right adrenal gland cortex, right adrenal gland

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
UQCC3	731
LBHD1	186

Structural data

PDB: 0 · AlphaFold-only: 2 · No structure: 0

AlphaFold-only cohort genes (top 30 by pLDDT)

Symbol	UniProt	pLDDT
UQCC3	Q6UW78	74.18
LBHD1	Q9BQE6	49.51

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 1. Enrichment computed across 2 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×	0.002	UQCC3

GO biological processes by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 2 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

GO term	Cohort genes	Fold	FDR	Sample cohort genes
mitochondrial electron transport, ubiquinol to cytochrome c	1	648.1×	0.003	UQCC3
mitochondrial respiratory chain complex III assembly	1	601.9×	0.003	UQCC3
cristae formation	1	526.6×	0.003	UQCC3
ATP biosynthetic process	1	495.6×	0.003	UQCC3
positive regulation of DNA-templated transcription	1	14.0×	0.070	LBHD1

Therapeutics

Drug target analysis

Approved (phase 4): 0 · Phase ≥3: 0 · Phased (≥1): 0 · Undrugged: 2

Druggability breadth: 0 of 2 evidence-associated genes (0%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
UQCC3	0	0
LBHD1	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 0.

Pharmacogenomics

Cohort genes with a PharmGKB record: 2; 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	0
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	2	UQCC3, LBHD1

Undrugged target profiles

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

Symbol	ChEMBL assays	Drugged partners (top 3)
UQCC3	0	—
LBHD1	0	—

Clinical trials & evidence

Clinical trials

Clinical trials: 0.

Cohort genes: UQCC3, LBHD1