22-50626234-A-G

Variant names:

• chr22-50626234-A-G
• rs199476389
• NM_000487.6:c.899T>C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000487.6(ARSA):​c.899T>C​(p.Leu300Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,252 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: ARSA NM_000487.6 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 5.14

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 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 22-50626234-A-G is Pathogenic according to our data. Variant chr22-50626234-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 68157.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr22-50626234-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ARSA	NM_000487.6	c.899T>C	p.Leu300Ser	missense_variant	Exon 5 of 8	ENST00000216124.10	NP_000478.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ARSA	ENST00000216124.10	c.899T>C	p.Leu300Ser	missense_variant	Exon 5 of 8	1	NM_000487.6	ENSP00000216124.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461252 Hom.: 0 Cov.: 35 AF XY: 0.00000550 AC XY: 4 AN XY: 726908

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000101

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Metachromatic leukodystrophy Pathogenic:2

Mar 19, 2025

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.899T>C (p.Leu300Ser), also reported as "L298S" and "L289S" [typo in publication], results in a non-conservative amino acid change in the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 248700 control chromosomes. c.899T>C has been reported in the presumed compound heterozygous state in the literature in multiple individuals affected with Metachromatic Leukodystrophy (example, Kurosawa_1998, Lee_2019, Santhanakumaran_2022, Cesani_2016). These data indicate that the variant is likely to 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 in vitro (example, Kurosawa_1998). The following publications have been ascertained in the context of this evaluation (PMID: 9819708, 31312839, 36240581, 19154224). ClinVar contains an entry for this variant (Variation ID: 68157). Based on the evidence outlined above, the variant was classified as pathogenic. -

May 09, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ARSA protein function. This sequence change replaces leucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 300 of the ARSA protein (p.Leu300Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with metachromatic leukodystrophy (PMID: 9819708, 31312839). This variant is also known as L298S. ClinVar contains an entry for this variant (Variation ID: 68157). Experimental studies have shown that this missense change affects ARSA function (PMID: 9819708, 31312839). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not provided Pathogenic:1 Other:1

-

UniProtKB/Swiss-Prot

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Nov 14, 2012

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.47
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.42	T;T;T;.;T
Eigen	Pathogenic	0.75
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.82	.;.;.;T;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.4	D;D;D;D;D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Vest4		0.97
MVP		0.96
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.97

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

LitVar

Other links and lift over

dbSNP: rs199476389; hg19: chr22-51064662;