dbSNP rs1554935669: SMPD1:p.His577Arg (chr11-6394441-A-G) – ACMG Classification: Pathogenic (11 pts)

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2PP3PP5_Very_Strong

The NM_000543.5(SMPD1):c.1730A>G(p.His577Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,614,054 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 Likely pathogenic (★★).

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6U:1

Conservation

PhyloP100: 7.13

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 11 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.748

PP5

Variant 11-6394441-A-G is Pathogenic according to our data. Variant chr11-6394441-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 550112.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.1730A>G	p.His577Arg	missense_variant	Exon 6 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.1730A>G	p.His577Arg	missense_variant	Exon 6 of 6	1	NM_000543.5	ENSP00000340409.4		P17405-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152166

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

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461888

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727244

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74334

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:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Niemann-Pick disease, type A

Pathogenic:2Uncertain:1

Mar 29, 2024

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 29, 2016

Counsyl

Significance: Uncertain significance

Review Status: flagged submission

Collection Method: clinical testing

- -

May 04, 2022

Mendelics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Pathogenic:2

Aug 16, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense change has been observed in individual(s) with Niemann-Pick disease (PMID: 20386867, 34273913). This sequence change replaces histidine, which is basic and polar, with arginine, which is basic and polar, at codon 577 of the SMPD1 protein (p.His577Arg). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 550112). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SMPD1 protein function. Experimental studies have shown that this missense change affects SMPD1 function (PMID: 20386867). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This variant disrupts the p.His577 amino acid residue in SMPD1. Other variant(s) that disrupt this residue have been observed in individuals with SMPD1-related conditions (PMID: 12712061, 20386867, 26499107), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

Apr 25, 2021

Diagnostics Division, CENTRE FOR DNA FINGERPRINTING AND DIAGNOSTICS

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

not provided

Pathogenic:1

Nov 03, 2022

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sphingomyelin/cholesterol lipidosis

Pathogenic:1

Aug 28, 2023

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SMPD1 c.1730A>G (p.His577Arg) results in a non-conservative amino acid change located in the Sphingomyelin phosphodiesterase, C-terminal domain (IPR045473) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251448 control chromosomes (gnomAD). c.1730A>G has been reported in the literature in compound heterozygous and homozygous individuals affected with Niemann-Pick Disease (Desnick_2010, Deshpande_2021). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function and p.H577R had less than 1% of expressed wild-type activity (Desnick_2010). The following publications have been ascertained in the context of this evaluation (PMID: 34273913, 20386867, 27435900). Five submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified this variant as uncertain significance (n=1, likely pathogenic (n=3) and pathogenic (n=1). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.31

CADD

Benign

DANN

Uncertain

0.99

Eigen

Uncertain

0.45

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.86

D;D

M_CAP

Benign

0.064

MetaRNN

Pathogenic

0.75

D;D

MetaSVM

Benign

-0.31

PrimateAI

Uncertain

0.69

PROVEAN

Uncertain

-2.9

D;D

REVEL

Pathogenic

0.80

Sift

Benign

0.27

T;T

Sift4G

Benign

0.43

T;T

Vest4

0.72

MVP

0.99

MPC

0.85

ClinPred

0.89

GERP RS

5.4

Varity_R

0.55

gMVP

0.80

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