chr11-6390895-C-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_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). Synonymous variant affecting the same amino acid position (i.e. T99T) has been classified as Likely benign.

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

Publications

0 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: Likely_benign. The variant received -6 ACMG points.

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 VariationId is 305196.

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

GnomAD2 exomes

AF:

0.000770

AC:

193

AN:

250596

AF XY:

0.000789

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 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

African (AFR)

AF:

0.0000597

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000580

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.000824

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00138

AC:

1540

AN:

1112006

Other (OTH)

AF:

0.000844

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.470

Heterozygous variant carriers

100

199

299

398

498

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

112

168

224

280

<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:

0.000690

AC:

105

AN:

152280

Hom.:

Cov.:

AF XY:

0.000403

AC XY:

AN XY:

74446

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41548

American (AMR)

AF:

0.0000654

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.00

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.000753

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00125

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.493

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

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. -

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). -

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. -

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

(source)

DANN

Benign

0.61

PhyloP100

-0.31

PromoterAI

-0.084

Neutral

(source)

Mutation Taster

=100/0

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over