dbSNP rs146630228: SMPD1:p.Thr99Thr (chr11-6390895-C-G) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2BP4_StrongBP6BP7

The NM_000543.5(SMPD1):c.297C>G(p.Thr99Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00108 in 1,614,148 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00069 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0011 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:5

Conservation

PhyloP100: -0.312

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 Likely_benign. Variant got -4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.63).

BP6

Variant 11-6390895-C-G is Benign according to our data. Variant chr11-6390895-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 305196.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=1}.

BP7

Synonymous conserved (PhyloP=-0.312 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5 link	c.297C>G	p.Thr99Thr	synonymous_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.297C>G	p.Thr99Thr	synonymous_variant	Exon 1 of 6	1	NM_000543.5	ENSP00000340409.4		P17405-1

Frequencies

GnomAD3 genomes

AF:

0.000690

AC:

105

AN:

152162

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00659

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000753

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00125

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000770

AC:

193

AN:

250596

Hom.:

AF XY:

0.000789

AC XY:

107

AN XY:

135686

show subpopulations

Gnomad AFR exome

AF:

0.0000626

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000980

Gnomad FIN exome

AF:

0.000787

Gnomad NFE exome

AF:

0.00145

Gnomad OTH exome

AF:

0.00115

GnomAD4 exome

AF:

0.00112

AC:

1643

AN:

1461868

Hom.:

Cov.:

AF XY:

0.00112

AC XY:

814

AN XY:

727232

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.000824

Gnomad4 NFE exome

AF:

0.00138

Gnomad4 OTH exome

AF:

0.000844

GnomAD4 genome

AF:

0.000690

AC:

105

AN:

152280

Hom.:

Cov.:

AF XY:

0.000403

AC XY:

AN XY:

74446

show subpopulations

Gnomad4 AFR

AF:

0.000120

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000753

Gnomad4 NFE

AF:

0.00125

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.00104

Hom.:

Bravo

AF:

0.000695

EpiCase

AF:

0.000818

EpiControl

AF:

0.00124

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Sphingomyelin/cholesterol lipidosis

Uncertain:1Benign:1

Jan 22, 2020

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: curation

The c.297C>G (p.Thr99=) variant in SMPD1 (also known as p.Thr97= due to a difference in cDNA numbering) has not been previously reported in individuals with Niemann-Pick disease, but has been identified in 0.141% (181/128754) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs146630228). This variant has also been reported in ClinVar (VariationID: 305196) as a VUS by Illumina Clinical Services Laboratory and as likely benign by Invitae. Computational prediction tools, including splice predictors, and conservation analyses suggest that this synonymous variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, although additional studies are required to fully establish its clinical significance, this variant is likely benign. ACMG/AMP Criteria applied: BS1, BP4, BP7 (Richards 2015). -

Nov 20, 2017

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Niemann-Pick disease, type A

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Inborn genetic diseases

Benign:1

May 06, 2022

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

SMPD1-related disorder

Benign:1

Mar 11, 2019

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

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

Benign:1

Aug 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Benign:1

Feb 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

SMPD1: BP4, BP7 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.63

CADD

Benign

7.7

DANN

Benign

0.61

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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