chr12-21131237-G-A

Position:

• chr12-21131237-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP3

The NM_006446.5(SLCO1B1):​c.-62+1G>A variant causes a splice donor change. The variant allele was found at a frequency of 0.0000263 in 151,982 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 32)
  • Failed GnomAD Quality Control
• Consequence: SLCO1B1 NM_006446.5 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.72

Genes affected

SLCO1B1 (HGNC:10959): (solute carrier organic anion transporter family member 1B1) This gene encodes a liver-specific member of the organic anion transporter family. The encoded protein is a transmembrane receptor that mediates the sodium-independent uptake of numerous endogenous compounds including bilirubin, 17-beta-glucuronosyl estradiol and leukotriene C4. This protein is also involved in the removal of drug compounds such as statins, bromosulfophthalein and rifampin from the blood into the hepatocytes. Polymorphisms in the gene encoding this protein are associated with impaired transporter function. [provided by RefSeq, Mar 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.020231213 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.5, offset of 42, new splice context is: tatGTaaga. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Multiple lines of computational evidence support a deleterious effect 4: Cadd, dbscSNV1_ADA, dbscSNV1_RF, max_spliceai [when BayesDel_noAF, Dann was below the threshold]

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLCO1B1	NM_006446.5	c.-62+1G>A		splice_donor_variant		ENST00000256958.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLCO1B1	ENST00000256958.3	c.-62+1G>A		splice_donor_variant		1	NM_006446.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 151982 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

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: 0.0000441

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AC: 0 AN: 0 Hom.: 0 Cov.: 0 AC XY: 0 AN XY: 0

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 151982 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74224

Gnomad4 AFR AF: 0.0000242

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Rotor syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

The SLCO1B1 c.-62+1G>A variant occurs in a canonical splice site (donor) and is therefore predicted to disrupt or distort the normal gene product. It was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018) and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score for this variant, it could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene and cDNA change. No publications were found based on this search. Due to the potential impact of splice donor variants and the lack of clarifying evidence, this variant is classified as a variant of unknown significance but suspicious for pathogenicity for Rotor syndrome. Note: bi-allelic variants in both the SLCO1B1 and SLCO1B3 genes combined have been shown to cause Rotor syndrome. For an individual to be affected with Rotor syndrome, they must carry a pathogenic variant in both copies of the SLCO1B1 gene and in both copies of the SLCO1B3 gene. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.13
CADD	Pathogenic	33
DANN	Benign	0.96

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.76
SpliceAI score (max)		0.91		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.25		Position offset: 41
DS_DL_spliceai		0.91		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs753044871; hg19: chr12-21284171;