Genetic Variant SMPD1:p.Val318Leu (chr11-6392017-G-C) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PM5

The NM_000543.5(SMPD1):c.952G>C(p.Val318Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. V318M) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.67

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:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 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 chr11-6392017-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 225625.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5 link	c.952G>C	p.Val318Leu	missense_variant	Exon 2 of 6	ENST00000342245.9	NP_000534.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD1	ENST00000342245.9 link	c.952G>C	p.Val318Leu	missense_variant	Exon 2 of 6	1	NM_000543.5	ENSP00000340409.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

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:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112012

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.44

BayesDel_addAF

Pathogenic

0.19

BayesDel_noAF

Uncertain

0.040

CADD

Benign

(source)

DANN

Benign

0.96

DEOGEN2

Benign

0.0

.;T;.

Eigen

Benign

-0.0013

Eigen_PC

Benign

0.17

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.89

D;D;D

M_CAP

Uncertain

0.092

MetaRNN

Uncertain

0.60

D;D;D

MetaSVM

Benign

-0.50

MutationAssessor

Benign

0.0

.;.;.

PhyloP100

7.7

PrimateAI

Uncertain

0.77

PROVEAN

Benign

-0.070

N;N;N

REVEL

Uncertain

0.55

Sift

Benign

0.88

T;T;T

Sift4G

Benign

0.67

T;T;T

Vest4

0.69

ClinPred

0.87

GERP RS

4.9

PromoterAI

-0.0044

Neutral

(source)

Varity_R

0.27

gMVP

0.88

Mutation Taster

=36/64

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.15

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over