rs121908580

Variant names:

• chr2-218661135-A-G
• rs121908580
• NM_001079866.2:c.148A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_001079866.2(BCS1L):​c.148A>G​(p.Thr50Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (no stars). Synonymous variant affecting the same amino acid position (i.e. T50T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BCS1L NM_001079866.2 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.30
• Publications: 13 publications found

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), PanelApp Australia, Orphanet, Ambry Genetics, ClinGen, G2P
• GRACILE syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
• Leigh syndrome

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: PanelApp Australia, ClinGen
• 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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_001079866.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.968
• PP5: Variant 2-218661135-A-G is Pathogenic according to our data. Variant chr2-218661135-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 6173.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCS1L	NM_001079866.2	c.148A>G	p.Thr50Ala	missense_variant	Exon 2 of 8	ENST00000359273.8	NP_001073335.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCS1L	ENST00000359273.8	c.148A>G	p.Thr50Ala	missense_variant	Exon 2 of 8	1	NM_001079866.2	ENSP00000352219.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 33

Alfa AF: 0.000131 Hom.: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Mitochondrial complex III deficiency nuclear type 1 Pathogenic:1

Feb 01, 2009

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.59
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.72	.;D;D;D;D;D;.;D;D;D;D;.
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.95	D;.;D;.;.;.;D;.;.;.;D;D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	.;.;.;M;M;M;.;M;M;M;M;.
PhyloP100		9.3
PrimateAI	Uncertain	0.78	T
PROVEAN	Uncertain	-3.7	D;D;D;D;D;D;D;D;D;D;D;.
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0060	D;T;T;T;T;T;D;T;T;T;T;.
Sift4G	Uncertain	0.0080	D;D;D;T;T;T;D;T;T;T;T;.
Polyphen		0.99	.;.;.;D;D;D;.;D;D;D;D;.
Vest4		0.90, 0.91, 0.89, 0.90, 0.90
MutPred		0.85		Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);
MVP		0.98
MPC		1.6
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.78
gMVP		0.87
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs121908580; hg19: chr2-219525858;