Genetic Variant NM_022166.4:c.1290-2A>G (chr16-17158911-T-C) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_022166.4(XYLT1):c.1290-2A>G variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,832 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: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

XYLT1
NM_022166.4 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.72

Publications

0 publications found

Variant links:

Genes affected

XYLT1 (HGNC:15516): (xylosyltransferase 1) This locus encodes a xylosyltransferase enzyme. The encoded protein catalyzes transfer of UDP-xylose to serine residues of an acceptor protein substrate. This transfer reaction is necessary for biosynthesis of glycosaminoglycan chains. Mutations in this gene have been associated with increased severity of pseudoxanthoma elasticum.[provided by RefSeq, Nov 2009]

XYLT1 Gene-Disease associations (from GenCC):

Desbuquois dysplasia 2
Inheritance: AR Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
Desbuquois dysplasia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
XYLT1-congenital disorder of glycosylation
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

XYLT1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.028125 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
XYLT1	NM_022166.4 link	c.1290-2A>G	splice_acceptor_variant, intron_variant	Intron 5 of 11	ENST00000261381.7	NP_071449.1	Q86Y38
XYLT1	XM_047434458.1 link	c.1251-2A>G	splice_acceptor_variant, intron_variant	Intron 4 of 10		XP_047290414.1
XYLT1	XM_017023539.3 link	c.1290-2A>G	splice_acceptor_variant, intron_variant	Intron 5 of 11		XP_016879028.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
XYLT1	ENST00000261381.7 link	c.1290-2A>G		splice_acceptor_variant, intron_variant	Intron 5 of 11	1	NM_022166.4	ENSP00000261381.6		Q86Y38

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461832

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727214

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111958

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.20

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.89

FATHMM_MKL

Uncertain

0.93

PhyloP100

6.7

GERP RS

4.9

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.98

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.98

Position offset: -2

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

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over