rs750433951

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 6P and 1B. PM1PM2PP5_ModerateBP4

The NM_000543.5(SMPD1):​c.1801G>A​(p.Ala601Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,612,326 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 Likely pathogenic (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 missense

Scores

1
8
9

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1U:1

Conservation

PhyloP100: 6.77

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)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM1
In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000543.5
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 11-6394512-G-A is Pathogenic according to our data. Variant chr11-6394512-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 555615.Status of the report is criteria_provided_single_submitter, 1 stars.
BP4
Computational evidence support a benign effect (MetaRNN=0.34562325). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SMPD1NM_000543.5 linkc.1801G>A p.Ala601Thr 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
SMPD1ENST00000342245.9 linkc.1801G>A p.Ala601Thr missense_variant Exon 6 of 6 1 NM_000543.5 ENSP00000340409.4 P17405-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152226
Hom.:
0
Cov.:
33
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
GnomAD2 exomes
AF:
0.00000400
AC:
1
AN:
249788
AF XY:
0.00000740
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000880
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1460100
Hom.:
0
Cov.:
34
AF XY:
0.00
AC XY:
0
AN XY:
726464
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51668
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111994
Other (OTH)
AF:
0.00
AC:
0
AN:
60378
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00000657
AC:
1
AN:
152226
Hom.:
0
Cov.:
33
AF XY:
0.0000134
AC XY:
1
AN XY:
74370
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41462
American (AMR)
AF:
0.00
AC:
0
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5184
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68044
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:1Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Niemann-Pick disease, type A;C0268243:Niemann-Pick disease, type B Pathogenic:1
Aug 04, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 601 of the SMPD1 protein (p.Ala601Thr). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. 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. ClinVar contains an entry for this variant (Variation ID: 555615). This missense change has been observed in individual(s) with acid sphingomyelinase deficiency (PMID: 27884455; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs750433951, gnomAD 0.0009%). -

Niemann-Pick disease, type A Uncertain:1
Dec 14, 2017
Counsyl
Significance:Uncertain significance
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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.47
BayesDel_addAF
Uncertain
0.078
D
BayesDel_noAF
Benign
-0.13
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Benign
0.30
T;.
Eigen
Benign
0.078
Eigen_PC
Uncertain
0.23
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Benign
0.78
T;T
M_CAP
Benign
0.036
D
MetaRNN
Benign
0.35
T;T
MetaSVM
Uncertain
-0.085
T
PhyloP100
6.8
PrimateAI
Uncertain
0.62
T
PROVEAN
Benign
-1.7
N;N
REVEL
Uncertain
0.34
Sift
Benign
0.21
T;T
Sift4G
Uncertain
0.012
D;D
Vest4
0.24
MVP
0.96
MPC
0.23
ClinPred
0.64
D
GERP RS
5.4
Varity_R
0.33
gMVP
0.62
Mutation Taster
=61/39
polymorphism

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

Other links and lift over

dbSNP: rs750433951; hg19: chr11-6415742; API