rs120074125

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM2PM5PP3

The NM_000543.5(SMPD1):​c.1177T>A​(p.Trp393Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,692 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W393G) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 missense

Scores

12
3
2

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.50

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)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM1
In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000543.5
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr11-6393301-T-G is described in ClinVar as Pathogenic. ClinVar VariationId is 2991.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SMPD1NM_000543.5 linkc.1177T>A p.Trp393Arg missense_variant Exon 3 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.1177T>A p.Trp393Arg missense_variant Exon 3 of 6 1 NM_000543.5 ENSP00000340409.4 P17405-1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461692
Hom.:
0
Cov.:
31
AF XY:
0.00000138
AC XY:
1
AN XY:
727132
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
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:
53402
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1111854
Other (OTH)
AF:
0.00
AC:
0
AN:
60374
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.98
BayesDel_addAF
Pathogenic
0.49
D
BayesDel_noAF
Pathogenic
0.46
CADD
Pathogenic
35
DANN
Uncertain
1.0
Eigen
Pathogenic
0.73
Eigen_PC
Uncertain
0.64
FATHMM_MKL
Pathogenic
0.97
D
LIST_S2
Benign
0.83
T;T
M_CAP
Pathogenic
0.82
D
MetaRNN
Pathogenic
0.99
D;D
MetaSVM
Uncertain
0.73
D
PhyloP100
7.5
PrimateAI
Pathogenic
0.80
D
PROVEAN
Pathogenic
-13
D;D
REVEL
Pathogenic
0.86
Sift
Pathogenic
0.0
D;D
Sift4G
Pathogenic
0.0
D;D
Vest4
0.99
MVP
0.97
MPC
1.1
ClinPred
1.0
D
GERP RS
4.0
Varity_R
0.97
gMVP
0.99
Mutation Taster
=0/100
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.51
Details are displayed if max score is > 0.2
DS_AG_spliceai
0.51
Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs120074125; hg19: chr11-6414531; API