rs398123478

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000543.5(SMPD1):c.1624C>T(p.Arg542Ter) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000229 in 1,614,218 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 Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R542R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000024 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:14

Conservation

PhyloP100: 3.67

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 38 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 11-6394335-C-T is Pathogenic according to our data. Variant chr11-6394335-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 93318.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-6394335-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMPD1	NM_000543.5 linkuse as main transcript	c.1624C>T	p.Arg542Ter	stop_gained	6/6	ENST00000342245.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMPD1	ENST00000342245.9 linkuse as main transcript	c.1624C>T	p.Arg542Ter	stop_gained	6/6	1	NM_000543.5	P3	P17405-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152210

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:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000637

AC:

AN:

251346

Hom.:

AF XY:

0.0000884

AC XY:

AN XY:

135812

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 SAS exome

AF:

0.000490

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000239

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000358

AC XY:

AN XY:

727246

show subpopulations

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:

0.000359

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152328

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74488

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000414

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ExAC

AF:

0.0000659

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:14

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type A

Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Mar 17, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics	Oct 27, 2023	A homozygous variation in exon 6 of the SMPD1 gene that results in a premature truncation of the protein at codon 542 was detected. The observed variant c.1624C>T(p.Arg542Ter) has not been reported in the 1000 genomes and has a MAF of 0.006% in gnomAD database. The in silico prediction of the variant is disease causing by DANN and MutationTaster. In summary, the variant meets our criteria to be classified as pathogenic. -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Apr 24, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 29, 2019	Variant summary: SMPD1 c.1624C>T (p.Arg542X) 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. The variant allele was found at a frequency of 6.4e-05 in 251346 control chromosomes, predominantly at a frequency of 0.00049 within the South Asian subpopulation in the gnomAD database. This frequency is not higher than expected for a pathogenic variant in SMPD1 causing Niemann-Pick Disease Type A (0.00049 vs 0.0022). c.1624C>T has been reported in the literature in multiple individuals affected with Niemann-Pick Disease Type A (Ranganath_2016). These data indicate that the variant is very likely to be associated with disease. Two ClinVar submitters (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Niemann-Pick disease, type B

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics	Jan 08, 2021	A heterozygous missense variation in exon 6 of the SMPD1 gene that results in a stop codon and premature truncation of the protein at codon 2482 was detected. The observed variant c.1624C>T (p.Arg542Ter) has not been reported in the 1000 genomes and has a MAF of 0.006% in the gnomAD databases. The in silico prediction of the variant is disease causing by DANN and MutationTaster. In summary, the variant meets our criteria to be classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Centogene AG - the Rare Disease Company	-	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Apr 24, 2015	- -

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

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 05, 2023	This sequence change creates a premature translational stop signal (p.Arg542*) in the SMPD1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 90 amino acid(s) of the SMPD1 protein. This variant is present in population databases (rs398123478, gnomAD 0.05%). This premature translational stop signal has been observed in individual(s) with Niemann-Pick disease (PMID: 22796693, 23188845, 27338287; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 93318). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Centogene AG - the Rare Disease Company	-	- -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 11, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Feb 17, 2017	- -

See cases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Nov 29, 2019

ACMG classification criteria: PVS1, PS4, PM2, PM3 -

Sphingomyelin/cholesterol lipidosis

Pathogenic:1

Pathogenic, criteria provided, single submitter

curation

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

Jan 22, 2020

The p.Arg542Ter variant in SMPD1 (also known as p.Arg540Ter due to a difference in cDNA numbering) has been reported in at least 14 individuals with Niemann-Pick disease (PMID: 22796693, 31139477, 27338287) and has been identified in 0.049% (15/30616) of South Asian chromosomes and 0.002% (1/113642) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs398123478). 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 on ClinVar (VariationID: 93318) as Pathogenic by EGL Genetic Diagnostics and Invitae. This nonsense variant leads to a premature termination codon at position 542. This alteration occurs within the last exon and is more likely to escape nonsense mediated decay (NMD) and result in a truncated protein without the C-terminus region, which is critical to protein function (PMID: 21098024, 18052040). Loss of function of the SMPD1 gene is an established disease mechanism in autosomal recessive Niemann-Pick disease. The presence of this variant in at least 11 affected homozygotes and in combination with reported pathogenic variants in 3 individuals with Niemann-Pick disease increases the likelihood that the p.Arg542Ter variant is pathogenic (PMID: 22796693, 31139477, 27338287). The phenotype of individuals homozygous and compound heterozygous for this variant is highly specific for Niemann-Pick disease based on acid sphingomyelinase activity being less than 10% of normal, consistent with disease (PMID: 27338287, 22796693). In summary, this variant meets criteria to be classified as pathogenic for Niemann-Pick disease in an autosomal recessive manner based on the predicted impact of the variant and multiple occurrences in the homozygous state and with pathogenic variants in affected individuals. ACMG/AMP Criteria applied: PVS1_strong, PM3_strong, PP4, PM2_supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.59

Cadd

Pathogenic

Dann

Uncertain

1.0

Eigen

Uncertain

0.50

Eigen_PC

Uncertain

0.30

FATHMM_MKL

Uncertain

0.79

MutationTaster

Benign

1.0

D;D;D;D

Vest4

0.91

GERP RS

4.0

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over