Genetic Variant ARSA:p.Pro193Thr (chr22-50626941-G-T) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1PM2PM5PP2PP3_StrongPP5

The NM_000487.6(ARSA):c.577C>A(p.Pro193Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,052 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P193R) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

ARSA
NM_000487.6 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:1O:1

Conservation

PhyloP100: 7.51

Publications

2 publications found

Variant links:

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]

ARSA Gene-Disease associations (from GenCC):

metachromatic leukodystrophy
Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health, ClinGen
metachromatic leukodystrophy, juvenile form
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp

ARSA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 14 uncertain in NM_000487.6

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr22-50626940-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 3366534.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 159 curated pathogenic missense variants (we use a threshold of 10). The gene has 11 curated benign missense variants. Gene score misZ: 0.38013 (below the threshold of 3.09). Trascript score misZ: -0.56919 (below the threshold of 3.09). GenCC associations: The gene is linked to metachromatic leukodystrophy, juvenile form, metachromatic leukodystrophy.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.979

PP5

Variant 22-50626941-G-T is Pathogenic according to our data. Variant chr22-50626941-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 68142.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000487.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
ARSA	NM_000487.6	MANE Select	c.577C>A	p.Pro193Thr	missense	Exon 3 of 8	NP_000478.3
ARSA	NM_001085425.3		c.577C>A	p.Pro193Thr	missense	Exon 4 of 9	NP_001078894.2
ARSA	NM_001085426.3		c.577C>A	p.Pro193Thr	missense	Exon 4 of 9	NP_001078895.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
ARSA	ENST00000216124.10	TSL:1 MANE Select	c.577C>A	p.Pro193Thr	missense	Exon 3 of 8	ENSP00000216124.5
ARSA	ENST00000356098.9	TSL:1	c.577C>A	p.Pro193Thr	missense	Exon 4 of 9	ENSP00000348406.5
ARSA	ENST00000395619.3	TSL:5	c.577C>A	p.Pro193Thr	missense	Exon 4 of 9	ENSP00000378981.3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152232

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000803

AC:

AN:

249054

AF XY:

0.00

show subpopulations

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000179

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1460820

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726718

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52458

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000809

AC:

AN:

1111944

Other (OTH)

AF:

0.00

AC:

AN:

60370

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.531

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152232

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74384

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41460

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4838

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000468

Hom.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Metachromatic leukodystrophy

Pathogenic:1

Jan 17, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 193 of the ARSA protein (p.Pro193Thr). This variant is present in population databases (rs199476374, gnomAD 0.002%). This missense change has been observed in individual(s) with metachromatic leukodystophy (PMID: 10381328). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as g.834C>A P191T. ClinVar contains an entry for this variant (Variation ID: 68142). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ARSA protein function with a positive predictive value of 95%. This variant disrupts the p.Pro193 amino acid residue in ARSA. Other variant(s) that disrupt this residue have been observed in individuals with ARSA-related conditions (PMID: 33185815), which suggests that this may be a clinically significant amino acid residue. 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 specified

Uncertain:1

Jun 18, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: ARSA c.577C>A (p.Pro193Thr) results in a non-conservative amino acid change located in the sulfatase, N-terminal domain (IPR000917) of the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 8e-06 in 249054 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.577C>A has been observed in individual(s) affected with Metachromatic Leukodystrophy(Qu_1999). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. This variant is also known as P191T. The following publications have been ascertained in the context of this evaluation (PMID: 32632536, 10381328). ClinVar contains an entry for this variant (Variation ID: 68142). Based on the evidence outlined above, the variant was classified as uncertain significance.

not provided

Other:1

UniProtKB/Swiss-Prot

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.38

BayesDel_addAF

Pathogenic

0.48

BayesDel_noAF

Pathogenic

0.47

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.40

Eigen

Pathogenic

0.75

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Uncertain

0.93

LIST_S2

Benign

0.83

M_CAP

Pathogenic

0.74

MetaRNN

Pathogenic

0.98

MetaSVM

Pathogenic

1.1

PhyloP100

7.5

PrimateAI

Uncertain

0.58

PROVEAN

Pathogenic

-7.7

REVEL

Pathogenic

0.93

Sift

Pathogenic

0.0

Sift4G

Uncertain

0.0060

Vest4

0.90

MVP

0.99

ClinPred

1.0

GERP RS

5.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

gMVP

0.94

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over