2-218662661-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001079866.2(BCS1L):c.871C>T(p.Arg291*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000409 in 1,613,894 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000040 ( 0 hom. )

Consequence

BCS1L
NM_001079866.2 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 2.54

Variant links:

Genes affected

BCS1L (HGNC:1020): (BCS1 homolog, ubiquinol-cytochrome c reductase complex chaperone) 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]

BCS1L links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-218662661-C-T is Pathogenic according to our data. Variant chr2-218662661-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 214162.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCS1L	NM_001079866.2 link	c.871C>T	p.Arg291*	stop_gained	Exon 6 of 8	ENST00000359273.8	NP_001073335.1	Q9Y276A0A024R445

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCS1L	ENST00000359273.8 link	c.871C>T	p.Arg291*	stop_gained	Exon 6 of 8	1	NM_001079866.2	ENSP00000352219.3		Q9Y276

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152076

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

250748

AF XY:

0.0000295

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000353

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000404

AC:

AN:

1461818

Hom.:

Cov.:

AF XY:

0.0000413

AC XY:

AN XY:

727214

show subpopulations

Gnomad4 AFR exome

AF:

0.00

AC:

AN:

33480

Gnomad4 AMR exome

AF:

0.0000224

AC:

AN:

44724

Gnomad4 ASJ exome

AF:

0.00

AC:

AN:

26136

Gnomad4 EAS exome

AF:

0.00

AC:

AN:

39700

Gnomad4 SAS exome

AF:

0.00

AC:

AN:

86232

Gnomad4 FIN exome

AF:

0.00

AC:

AN:

53376

Gnomad4 NFE exome

AF:

0.0000477

AC:

AN:

1112012

Gnomad4 Remaining exome

AF:

0.0000828

AC:

AN:

60396

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152076

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74292

show subpopulations

Gnomad4 AFR

AF:

0.0000483

AC:

0.0000483279

AN:

0.0000483279

Gnomad4 AMR

AF:

0.00

AC:

AN:

Gnomad4 ASJ

AF:

0.00

AC:

AN:

Gnomad4 EAS

AF:

0.00

AC:

AN:

Gnomad4 SAS

AF:

0.00

AC:

AN:

Gnomad4 FIN

AF:

0.00

AC:

AN:

Gnomad4 NFE

AF:

0.0000735

AC:

0.0000735056

AN:

0.0000735056

Gnomad4 OTH

AF:

0.00

AC:

AN:

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000927

Hom.:

Bravo

AF:

0.0000529

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000494

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Pili torti-deafness syndrome

Pathogenic:3

Mar 12, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 30, 2023

Molecular Genetics, Royal Melbourne Hospital

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature termination codon at position 291 in exon 7 (of 9) of BCS1L, p.(Arg291*). It is expected to result in an absent or disrupted protein product in a gene where loss of function is an established mechanism of disease. The variant is present in a large population cohort at a frequency of 0.003%, which is consistent with a recessive condition (rs201454788, 8/282,138 alleles, 0 homozygotes in gnomAD v2.1). The variant has been identified compound heterozygous with a second allele in a case diagnosed with Bjornstad syndrome (PMID: 17314340). Additionally, the variant demonstrates attenuated growth in a yeast complementation assay (PMID: 17314340). Based on the classification scheme RMH ACMG Guidelines v1.2.1, this variant is classified as PATHOGENIC. Following criteria are met: PVS1, PM2, PS3_Supporting. -

Nov 14, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BCS1L c.871C>T (p.Arg291X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 2e-05 in 250748 control chromosomes (gnomAD). c.871C>T has been reported in the literature in a compound heterozygote individual affected with Bjornstad syndrome (Hinson_2007). The authors of this study also reported experimental evidence evaluating an impact on protein function, demonstrating in a yeast complementation assay that the mutant protein failed to rescue growth on a medium that requires an active respiratory-chain. They also showed decreased electron-transport activities with increased production of reactive oxygen species in lymphocytes acquired from patients with Bjornstad syndrome and complex III deficiency (however, no patient specific data were provided, Hinson_2007). Five ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=1), likely pathogenic (n=1) and pathogenic (n=3). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

GRACILE syndrome

Pathogenic:2

Apr 11, 2017

Counsyl

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:2

Sep 01, 2022

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate a damaging effect as this variant results in mitochondrial dysfunction with reduced electron transport chain activity (Hinson et al., 2007); This variant is associated with the following publications: (PMID: 25525159, 29704315, 25914718, 17314340) -

Aug 06, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg291*) in the BCS1L gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BCS1L are known to be pathogenic (PMID: 12215968, 17314340, 19162478, 19508421, 22277166, 25895478). This variant is present in population databases (rs201454788, gnomAD 0.005%). This premature translational stop signal has been observed in individual(s) with Bjornstad syndrome (PMID: 17314340). ClinVar contains an entry for this variant (Variation ID: 214162). For these reasons, this variant has been classified as Pathogenic. -

Pili torti-deafness syndrome;C1864002:GRACILE syndrome;C3541471:Mitochondrial complex III deficiency nuclear type 1

Pathogenic:1

May 27, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.54

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

0.79

Eigen_PC

Uncertain

0.63

FATHMM_MKL

Uncertain

0.88

Vest4

0.98

ClinPred

1.0

GERP RS

4.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=0/200

disease causing (ClinVar)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.13

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over