Genetic Variant SMPD1:p.Arg602Leu (chr11-6394516-G-T) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PM5PP3_Moderate

The NM_000543.5(SMPD1):c.1805G>T(p.Arg602Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,459,778 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. R602C) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 8.39

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 8 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, 6 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 chr11-6394515-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 878168.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.853

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5 link	c.1805G>T	p.Arg602Leu	missense_variant	Exon 6 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.1805G>T	p.Arg602Leu	missense_variant	Exon 6 of 6	1	NM_000543.5	ENSP00000340409.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000206

AC:

AN:

1459778

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726322

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

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:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51364

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111976

Other (OTH)

AF:

0.00

AC:

AN:

60380

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

0.46

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.35

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Uncertain

0.43

Eigen_PC

Uncertain

0.47

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Benign

0.82

T;T

M_CAP

Uncertain

0.11

MetaRNN

Pathogenic

0.85

D;D

MetaSVM

Benign

-0.42

PhyloP100

8.4

PrimateAI

Uncertain

0.66

PROVEAN

Pathogenic

-4.6

D;D

REVEL

Uncertain

0.61

Sift

Uncertain

0.0030

D;D

Sift4G

Benign

0.12

T;T

Vest4

0.82

MVP

0.95

MPC

0.63

ClinPred

0.99

GERP RS

5.4

Varity_R

0.77

gMVP

0.84

Mutation Taster

=11/89

disease causing

(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

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