8-19405784-GTT-G

Position:

• chr8-19405784-GTT-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PM4

The NM_001354483.2(CSGALNACT1):​c.1593_1594del​(p.Lys531AsnfsTer31) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,852 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CSGALNACT1 NM_001354483.2 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.981

Genes affected

CSGALNACT1 (HGNC:24290): (chondroitin sulfate N-acetylgalactosaminyltransferase 1) This gene encodes an enzyme that transfers N-acetylglucosamine (GalNAc) to the core tetrasaccharide linker and to elongating chondroitin sulfate chains in proteoglycans. Knockout of the orthologous mouse gene indicates that the protein is necessary for normal cartilage development and aggrecan metabolism. Mutations in this gene are associated with multiple sclerosis progression, and with mild skeletal dysplasia and joint laxity. [provided by RefSeq, Aug 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Frameshift in the end of transcript resulting in stoplost. Downstream stopcodon found after 544 codons.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CSGALNACT1	NM_001354483.2	c.1593_1594del	p.Lys531AsnfsTer31	frameshift_variant	9/9	ENST00000692225.2	NP_001341412.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CSGALNACT1	ENST00000692225.2	c.1593_1594del	p.Lys531AsnfsTer31	frameshift_variant	9/9		NM_001354483.2	ENSP00000509853	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461852 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727234

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 10, 2022

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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant has not been reported in the literature in individuals affected with CSGALNACT1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change results in a frameshift in the CSGALNACT1 gene (p.Lys531Asnfs*31). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 2 amino acid(s) of the CSGALNACT1 protein and extend the protein by 28 additional amino acid residues. -

Computational scores

Source: dbNSFP v4.3

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr8-19263295;