chr22-50627390-C-CG

Variant names:

• chr22-50627390-C-CG
• rs786204599
• NM_000487.6:c.240dupC

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000487.6(ARSA):​c.240dupC​(p.Gly81ArgfsTer53) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000302 in 1,455,678 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000030 (0 hom.)
• Consequence: ARSA NM_000487.6 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -1.13

Genes affected

ARSA (HGNC:713): (arylsulfatase A) The protein encoded by this gene hydrolyzes cerebroside sulfate to cerebroside and sulfate. Defects in this gene lead to metachromatic leucodystrophy (MLD), a progressive demyelination disease which results in a variety of neurological symptoms and ultimately death. Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Dec 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 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
• PP5: Variant 22-50627390-C-CG is Pathogenic according to our data. Variant chr22-50627390-C-CG is described in ClinVar as [Likely_pathogenic]. Clinvar id is 188976.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ARSA	NM_000487.6	c.240dupC	p.Gly81ArgfsTer53	frameshift_variant	Exon 2 of 8	ENST00000216124.10	NP_000478.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ARSA	ENST00000216124.10	c.240dupC	p.Gly81ArgfsTer53	frameshift_variant	Exon 2 of 8	1	NM_000487.6	ENSP00000216124.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000430 AC: 1 AN: 232650 Hom.: 0 AF XY: 0.00000779 AC XY: 1 AN XY: 128394

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000961

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000302 AC: 44 AN: 1455678 Hom.: 0 Cov.: 33 AF XY: 0.0000345 AC XY: 25 AN XY: 724052

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: 0.0000396

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Metachromatic leukodystrophy Pathogenic:3

Sep 23, 2014

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: literature only

- -

Apr 16, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gly81Argfs*53) in the ARSA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ARSA are known to be pathogenic (PMID: 8962139, 10477432). This variant is present in population databases (rs786204599, gnomAD 0.001%). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 188976). This variant is also known as c.234dupC. This premature translational stop signal has been observed in individual(s) with metachromatic leukodystrophy (PMID: 17438611). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. -

Jan 31, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ARSA c.240dupC (p.Gly81ArgfsX53) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 4.3e-06 in 232650 control chromosomes. c.240dupC has been reported in the literature in individuals affected with Metachromatic Leukodystrophy (Waye_2007, Calbi_2018). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal activity (Calbi_2018). One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs786204599; hg19: chr22-51065818;