2-233760405-T-C

Variant names:

• chr2-233760405-T-C
• rs1183811071
• NM_000463.3:c.118T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_000463.3(UGT1A1):​c.118T>C​(p.Trp40Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000149 in 1,614,126 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: UGT1A1 NM_000463.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.98

Genes affected

UGT1A1 (HGNC:12530): (UDP glucuronosyltransferase family 1 member A1) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The preferred substrate of this enzyme is bilirubin, although it also has moderate activity with simple phenols, flavones, and C18 steroids. Mutations in this gene result in Crigler-Najjar syndromes types I and II and in Gilbert syndrome. [provided by RefSeq, Jul 2008]

UGT1A4 (HGNC:12536): (UDP glucuronosyltransferase family 1 member A4) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. This enzyme has some glucuronidase activity towards bilirubin, although is is more active on amines, steroids, and sapogenins. [provided by RefSeq, Jul 2008]

UGT1A5 (HGNC:12537): (UDP glucuronosyltransferase family 1 member A5) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. [provided by RefSeq, Jul 2008]

UGT1A3 (HGNC:12535): (UDP glucuronosyltransferase family 1 member A3) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. Substrates of this enzyme include estrone, 2-hydroxyestrone, and metabolites of benzo alpha-pyrene. [provided by RefSeq, Jul 2008]

UGT1A6 (HGNC:12538): (UDP glucuronosyltransferase family 1 member A6) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene is active on phenolic and planar compounds. Alternative splicing in the unique 5' end of this gene results in two transcript variants. [provided by RefSeq, Jul 2008]

UGT1A10 (HGNC:12531): (UDP glucuronosyltransferase family 1 member A10) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene has glucuronidase activity on mycophenolic acid, coumarins, and quinolines. [provided by RefSeq, Jul 2008]

UGT1A8 (HGNC:12540): (UDP glucuronosyltransferase family 1 member A8) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene has glucuronidase activity with many substrates including coumarins, phenols, anthraquinones, flavones, and some opioids. [provided by RefSeq, Jul 2008]

UGT1A7 (HGNC:12539): (UDP glucuronosyltransferase family 1 member A7) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene has moderate glucuronidase activity with phenols. [provided by RefSeq, Jul 2008]

UGT1A9 (HGNC:12541): (UDP glucuronosyltransferase family 1 member A9) This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene is active on phenols. [provided by RefSeq, Jul 2008]

UGT1A (HGNC:12529):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 5 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: -0.2468 (below the threshold of 3.09). Trascript score misZ: 0.17712 (below the threshold of 3.09). GenCC associations: The gene is linked to Crigler-Najjar syndrome type 2, Gilbert syndrome, Crigler-Najjar syndrome type 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
UGT1A1	NM_000463.3	c.118T>C	p.Trp40Arg	missense_variant	Exon 1 of 5	ENST00000305208.10	NP_000454.1
UGT1A4	NM_007120.3	c.868-6629T>C		intron_variant	Intron 1 of 4	ENST00000373409.8	NP_009051.1
UGT1A5	NM_019078.2	c.868-6629T>C		intron_variant	Intron 1 of 4	ENST00000373414.4	NP_061951.1
UGT1A3	NM_019093.4	c.868-6629T>C		intron_variant	Intron 1 of 4	ENST00000482026.6	NP_061966.1
UGT1A6	NM_001072.4	c.862-6629T>C		intron_variant	Intron 1 of 4	ENST00000305139.11	NP_001063.2
UGT1A10	NM_019075.4	c.856-6629T>C		intron_variant	Intron 1 of 4	ENST00000344644.10	NP_061948.1
UGT1A8	NM_019076.5	c.856-6629T>C		intron_variant	Intron 1 of 4	ENST00000373450.5	NP_061949.3
UGT1A7	NM_019077.3	c.856-6629T>C		intron_variant	Intron 1 of 4	ENST00000373426.4	NP_061950.2
UGT1A9	NM_021027.3	c.856-6629T>C		intron_variant	Intron 1 of 4	ENST00000354728.5	NP_066307.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
UGT1A1	ENST00000305208.10	c.118T>C	p.Trp40Arg	missense_variant	Exon 1 of 5	1	NM_000463.3	ENSP00000304845.5
UGT1A4	ENST00000373409.8	c.868-6629T>C		intron_variant	Intron 1 of 4	1	NM_007120.3	ENSP00000362508.4
UGT1A5	ENST00000373414.4	c.868-6629T>C		intron_variant	Intron 1 of 4	1	NM_019078.2	ENSP00000362513.3
UGT1A3	ENST00000482026.6	c.868-6629T>C		intron_variant	Intron 1 of 4	1	NM_019093.4	ENSP00000418532.1
UGT1A6	ENST00000305139.11	c.862-6629T>C		intron_variant	Intron 1 of 4	1	NM_001072.4	ENSP00000303174.6
UGT1A10	ENST00000344644.10	c.856-6629T>C		intron_variant	Intron 1 of 4	1	NM_019075.4	ENSP00000343838.5
UGT1A9	ENST00000354728.5	c.856-6629T>C		intron_variant	Intron 1 of 4	1	NM_021027.3	ENSP00000346768.4
UGT1A7	ENST00000373426.4	c.856-6629T>C		intron_variant	Intron 1 of 4	1	NM_019077.3	ENSP00000362525.3
UGT1A8	ENST00000373450.5	c.856-6629T>C		intron_variant	Intron 1 of 4	1	NM_019076.5	ENSP00000362549.4

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152238 Hom.: 0 Cov.: 33

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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.0000150 AC: 22 AN: 1461888 Hom.: 0 Cov.: 34 AF XY: 0.0000124 AC XY: 9 AN XY: 727248

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

American (AMR) AF: 0.00 AC: 0 AN: 44722

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: 0.0000180 AC: 20 AN: 1112012

Other (OTH) AF: 0.0000331 AC: 2 AN: 60394

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152238 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74386

African (AFR) AF: 0.00 AC: 0 AN: 41458

American (AMR) AF: 0.00 AC: 0 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5200

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 06, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 40 of the UGT1A1 protein (p.Trp40Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of Crigler-Najjar syndrome (Invitae). Compound heterozygous individuals for this variant present with Crigler-Najjar syndrome type II (PMID: 16712705). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt UGT1A1 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.65	D;.
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.90	D;T
M_CAP	Pathogenic	0.49	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Uncertain	0.48	D
MutationAssessor	Pathogenic	4.4	H;H
PhyloP100		8.0
PROVEAN	Pathogenic	-12	D;D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.95
MutPred		0.96		Gain of disorder (P = 0.0788);Gain of disorder (P = 0.0788);
MVP		0.86
MPC		0.74
ClinPred		1.0	D
GERP RS		6.1
PromoterAI		0.016	Neutral
Varity_R		0.91
gMVP		0.92
Mutation Taster		=9/91	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

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Other links and lift over

dbSNP: rs1183811071; hg19: chr2-234669051;