2-218661308-G-C

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_StrongPM2

The NM_001079866.2(BCS1L):c.320+1G>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,218 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Consequence

BCS1L
NM_001079866.2 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.98

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

Bjornstad syndrome
Inheritance: AR, AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, ClinGen, Ambry Genetics
GRACILE syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
mitochondrial complex III deficiency nuclear type 1
Inheritance: AR Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
mitochondrial complex III deficiency
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
renal tubulopathy-encephalopathy-liver failure syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Leigh syndrome
Inheritance: AR Classification: LIMITED Submitted by: ClinGen

BCS1L links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.29285714 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.9, offset of 5, new splice context is: aagGTgggg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001079866.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
BCS1L	NM_001079866.2	MANE Select	c.320+1G>C	splice_donor intron	N/A	NP_001073335.1	Q9Y276
BCS1L	NM_001257342.2		c.320+1G>C	splice_donor intron	N/A	NP_001244271.1	Q9Y276
BCS1L	NM_001257343.2		c.320+1G>C	splice_donor intron	N/A	NP_001244272.1	A0A024R445

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
BCS1L	ENST00000359273.8	TSL:1 MANE Select	c.320+1G>C	splice_donor intron	N/A	ENSP00000352219.3	Q9Y276
BCS1L	ENST00000392109.5	TSL:1	c.320+1G>C	splice_donor intron	N/A	ENSP00000375957.1	Q9Y276
BCS1L	ENST00000392111.7	TSL:1	c.320+1G>C	splice_donor intron	N/A	ENSP00000375959.2	Q9Y276

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152218

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000399

AC:

AN:

250504

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152218

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74370

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.000207

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

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:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.52

BayesDel_noAF

Uncertain

0.040

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.95

FATHMM_MKL

Uncertain

0.97

PhyloP100

GERP RS

4.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.95

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.61

Position offset: 4

DS_DL_spliceai

0.95

Position offset: -1

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over