BCS1L

Chr 2AR

BCS1 ubiquinol-cytochrome c reductase complex chaperone

Also known as: BCS, BCS1, BJS, FLNMS, GRACILE, Hs.6719, MC3DN1, PTD

This gene encodes a homolog of the S. cerevisiae bcs1 protein which is involved in the assembly of complex III of the mitochondrial respiratory chain. The encoded protein does not contain a mitochondrial targeting sequence but experimental studies confirm that it is imported into mitochondria. Mutations in this gene are associated with mitochondrial complex III deficiency and the GRACILE syndrome. Several alternatively spliced transcripts encoding two different isoforms have been described. [provided by RefSeq, Jan 2016]

GeneReviewsOMIMResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Bjornstad syndromeMIM #262000
AR
GRACILE syndromeMIM #603358
AR
Mitochondrial complex III deficiency, nuclear type 1MIM #124000
AR
UniProtBjoernstad syndrome

Clinical highlights

Gene-disease validity (ClinGen)
Leigh syndrome · ARLimitednot for standalone diagnostic reporting3 gene-disease associations curated in total
Interpreting a novel variant
Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.
0
Active trials
8
Pubs (1 yr)
P/LP submissions
P/LP missense
1.24
LOEUF
LOF
Mechanism· G2P
📖
GeneReview available — BCS1L
Authoritative clinical overview · Recommended first read
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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint?
1.24LOEUF
pLI 0.000
Z-score 0.65
OE 0.86 (0.611.24)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?
1.62Z-score
OE missense 0.71 (0.620.80)
170 obs / 240.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?
LoF OE?0.86 (0.611.24)
00.351.4
Missense OE?0.71 (0.620.80)
00.61.4
Synonymous OE?1.06
01.21.6
LoF obs/exp: 21 / 24.5Missense obs/exp: 170 / 240.5Syn Z: -0.48

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

BCS1L · protein map & ClinVar variants

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

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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