rs1057516949

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000543.5(SMPD1):c.151_154delGACT(p.Asp51LeufsTer25) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000749 in 1,601,852 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. D51D) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000067 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 1.84

Publications

1 publications found

Variant links:

Genes affected

SMPD1 (HGNC:11120): (sphingomyelin phosphodiesterase 1) The protein encoded by this gene is a lysosomal acid sphingomyelinase that converts sphingomyelin to ceramide. The encoded protein also has phospholipase C activity. Defects in this gene are a cause of Niemann-Pick disease type A (NPA) and Niemann-Pick disease type B (NPB). Multiple transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2010]

SMPD1 Gene-Disease associations (from GenCC):

acid sphingomyelinase deficiency
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
Niemann-Pick disease
Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
Niemann-Pick disease type A
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
Niemann-Pick disease type B
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)

SMPD1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 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 11-6390746-TCTGA-T is Pathogenic according to our data. Variant chr11-6390746-TCTGA-T is described in ClinVar as [Pathogenic]. Clinvar id is 371029.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
SMPD1	NM_000543.5 link	c.151_154delGACT	p.Asp51LeufsTer25	frameshift_variant	Exon 1 of 6	ENST00000342245.9	NP_000534.3	P17405-1Q59EN6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD1	ENST00000342245.9 link	c.151_154delGACT	p.Asp51LeufsTer25	frameshift_variant	Exon 1 of 6	1	NM_000543.5	ENSP00000340409.4		P17405-1

Frequencies

GnomAD3 genomes

AF:

0.00000665

AC:

AN:

150292

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:

0.0000149

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000805

AC:

AN:

248452

AF XY:

0.0000149

show subpopulations

Gnomad AFR exome

AF:

0.0000629

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:

0.00000891

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000758

AC:

AN:

1451560

Hom.:

AF XY:

0.0000125

AC XY:

AN XY:

722342

show subpopulations

African (AFR)

AF:

0.0000300

AC:

AN:

33376

American (AMR)

AF:

0.00

AC:

AN:

44666

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26124

East Asian (EAS)

AF:

0.00

AC:

AN:

39620

South Asian (SAS)

AF:

0.00

AC:

AN:

85798

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52984

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5742

European-Non Finnish (NFE)

AF:

0.00000906

AC:

AN:

1103188

Other (OTH)

AF:

0.00

AC:

AN:

60062

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000665

AC:

AN:

150292

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

73338

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41052

American (AMR)

AF:

0.00

AC:

AN:

15178

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3462

East Asian (EAS)

AF:

0.00

AC:

AN:

5094

South Asian (SAS)

AF:

0.00

AC:

AN:

4754

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10276

Middle Eastern (MID)

AF:

0.00

AC:

AN:

308

European-Non Finnish (NFE)

AF:

0.0000149

AC:

AN:

67232

Other (OTH)

AF:

0.00

AC:

AN:

2070

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type A

Pathogenic:3

Sep 07, 2023

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 22, 2020

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:curation

The p.Asp51LeufsTer25 variant in SMPD1 (also known as p.Asp49LeufsTer25 due to a difference in cDNA numbering) has been reported in one Cambodian individual with Niemann-Pick disease (PMID: 24718843) and has been identified in 0.006% (1/15898) of African chromosomes and 0.001% (1/112280) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs1057516949). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (VariationID: 371029) as likely pathogenic by Counsyl. This variant is predicted to cause a frameshift, which alters the protein's amino acid sequence beginning at position 51 and leads to a premature termination codon 25 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the SMPD1 gene is an established disease mechanism in autosomal recessive Niemann-Pick disease. The phenotype of an individual compound heterozygous for this variant is highly specific for Niemann-Pick disease based on acid sphingomyelinase activity being <10% of normal, consistent with disease (PMID: 24718843). In summary, this variant meets criteria to be classified as pathogenic for Niemann-Pick disease in an autosomal recessive manner based on the prediction that it will cause loss of function, the phenotype of an individual with the variant being highly specific for disease, and the low frequency of the variant in the general population. ACMG/AMP Criteria applied: PVS1, PM2, PP4 (Richards 2015). -

Jun 08, 2016

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Niemann-Pick disease, type A;C0268243:Niemann-Pick disease, type B

Pathogenic:1

Feb 01, 2024

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.Asp51Leufs*25) in the SMPD1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SMPD1 are known to be pathogenic (PMID: 12369017, 15221801). This variant is present in population databases (no rsID available, gnomAD 0.007%). This premature translational stop signal has been observed in individual(s) with acid sphingomyelinase-deficient Niemann-Pick disease (PMID: 24718843). ClinVar contains an entry for this variant (Variation ID: 371029). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.8

Mutation Taster

=3/197

disease causing (ClinVar)

(source)

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

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rs1057516949

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over