NM_005660.3:c.818_819delGCinsCG

Variant names:

• chrX-48905090-GC-CG
• NM_005660.3:c.818_819delGCinsCG
• SLC35A2 p.Gly273Ala

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM1

The NM_005660.3(SLC35A2):​c.818_819delGCinsCG​(p.Gly273Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G273D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 23)
• Consequence: SLC35A2 NM_005660.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.89
• Publications: 0 publications found

Genes affected

SLC35A2 (HGNC:11022): (solute carrier family 35 member A2) This gene encodes a member of the nucleotide-sugar transporter family. The encoded protein is a multi-pass membrane protein. It transports UDP-galactose from the cytosol into Golgi vesicles, where it serves as a glycosyl donor for the generation of glycans. Mutations in this gene cause congenital disorder of glycosylation type IIm (CDG2M). Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Oct 2014]

SLC35A2 Gene-Disease associations (from GenCC):

• SLC35A2-congenital disorder of glycosylation

  Inheritance: XL, Unknown Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, Orphanet, Illumina, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• X-linked complex neurodevelopmental disorder

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_005660.3

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005660.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SLC35A2	NM_005660.3	MANE Select	c.818_819delGCinsCG	p.Gly273Ala	missense	N/A	NP_005651.1	P78381-1
	SLC35A2	NM_001282651.2		c.902_903delGCinsCG	p.Gly301Ala	missense	N/A	NP_001269580.1	P78381-4
	SLC35A2	NM_001282650.2		c.857_858delGCinsCG	p.Gly286Ala	missense	N/A	NP_001269579.1	B4DE15

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SLC35A2	ENST00000247138.11	TSL:1 MANE Select	c.818_819delGCinsCG	p.Gly273Ala	missense	N/A	ENSP00000247138.5	P78381-1
	SLC35A2	ENST00000376521.6	TSL:1	c.818_819delGCinsCG	p.Gly273Ala	missense	N/A	ENSP00000365704.1	P78381-2
	SLC35A2	ENST00000445167.7	TSL:1	c.427-199_427-198delGCinsCG		intron	N/A	ENSP00000402726.2	P78381-3

Frequencies

GnomAD3 genomes Cov.: 23

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 23

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.9

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chrX-48762367;