dbSNP rs750433951: SMPD1:p.Ala601Thr (chr11-6394512-G-A) – ACMG Classification: Likely_pathogenic (7 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 8P and 1B. PM1PM2PM5PP5_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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A601V) has been classified 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

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

Conservation

PhyloP100: 6.77

Publications

2 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: Orphanet, G2P, PanelApp Australia, Genomics England PanelApp
Niemann-Pick disease type B
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)

SMPD1 links:

Genome browser will be placed here

new If you want to explore the variant's impact on the transcript NM_000543.5, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 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 chr11-6394513-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 4535161.Status of the report is criteria_provided_single_submitter, 1 stars.

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 VariationId 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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000543.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
SMPD1	NM_000543.5	MANE Select	c.1801G>A	p.Ala601Thr	missense	Exon 6 of 6	NP_000534.3
SMPD1	NM_001007593.3		c.1798G>A	p.Ala600Thr	missense	Exon 6 of 6	NP_001007594.2	P17405-4
SMPD1	NM_001365135.2		c.1669G>A	p.Ala557Thr	missense	Exon 5 of 5	NP_001352064.1	P17405-2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
SMPD1	ENST00000342245.9	TSL:1 MANE Select	c.1801G>A	p.Ala601Thr	missense	Exon 6 of 6	ENSP00000340409.4	P17405-1
SMPD1	ENST00000526280.1	TSL:1	c.856G>A	p.Ala286Thr	missense	Exon 4 of 4	ENSP00000436278.1	H0YEP5
SMPD1	ENST00000531303.5	TSL:1	n.*652G>A		non_coding_transcript_exon	Exon 6 of 6	ENSP00000432625.1	E9PPK6

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152226

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

GnomAD2 exomes

AF:

0.00000400

AC:

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:

AN:

1460100

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726464

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44722

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:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51668

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111994

Other (OTH)

AF:

0.00

AC:

AN:

60378

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

AF:

0.00000657

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74370

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68044

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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

ClinVar

ClinVar submissions

Significance:Likely pathogenic

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

Niemann-Pick disease, type A (1)

Niemann-Pick disease, type A;C0268243:Niemann-Pick disease, type B (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.47

BayesDel_addAF

Uncertain

0.078

BayesDel_noAF

Benign

-0.13

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.30

Eigen

Benign

0.078

Eigen_PC

Uncertain

0.23

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Benign

0.78

M_CAP

Benign

0.036

MetaRNN

Benign

0.35

MetaSVM

Uncertain

-0.085

PhyloP100

6.8

PrimateAI

Uncertain

0.62

PROVEAN

Benign

-1.7

REVEL

Uncertain

0.34

Sift

Benign

0.21

Sift4G

Uncertain

0.012

Varity_R

0.33

gMVP

0.62

Mutation Taster

=61/39

polymorphism

(source)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over