NM_022166.4:c.276delG

Variant names:

• chr16-17470520-GC-G
• rs587777369
• NM_022166.4:c.276delG

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_022166.4(XYLT1):​c.276delG​(p.Gln94ArgfsTer100) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 9.3e-7 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: XYLT1 NM_022166.4 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.366
• Publications: 2 publications found

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

LOC107987234 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_022166.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	XYLT1	NM_022166.4	MANE Select	c.276delG	p.Gln94ArgfsTer100	frameshift	Exon 1 of 12	NP_071449.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	XYLT1	ENST00000261381.7	TSL:1 MANE Select	c.276delG	p.Gln94ArgfsTer100	frameshift	Exon 1 of 12	ENSP00000261381.6

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00 AC: 0 AN: 488 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 9.29e-7 AC: 1 AN: 1076760 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 509236

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

African (AFR) AF: 0.00 AC: 0 AN: 22680

American (AMR) AF: 0.00 AC: 0 AN: 8220

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 14104

East Asian (EAS) AF: 0.00 AC: 0 AN: 26292

South Asian (SAS) AF: 0.00 AC: 0 AN: 19702

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 21072

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2922

European-Non Finnish (NFE) AF: 0.00000109 AC: 1 AN: 918506

Other (OTH) AF: 0.00 AC: 0 AN: 43262

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.37

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

Other links and lift over

dbSNP: rs587777369; hg19: chr16-17564377;