11-6391795-G-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PS1_ModeratePM1PM2PM5PP3_Moderate

The NM_000543.5(SMPD1):c.730G>C(p.Gly244Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,226 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G244A) has been classified as Likely 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: 9.25

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: Pathogenic. The variant received 10 ACMG points.

PS1

Transcript NM_000543.5 (SMPD1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.

PM1

In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 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 chr11-6391796-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1524692.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.939

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5 link	c.730G>C	p.Gly244Arg	missense_variant	Exon 2 of 6	ENST00000342245.9	NP_000534.3	P17405-1Q59EN6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD1	ENST00000342245.9 link	c.730G>C	p.Gly244Arg	missense_variant	Exon 2 of 6	1	NM_000543.5	ENSP00000340409.4		P17405-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460226

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726520

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:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44720

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:

51794

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111998

Other (OTH)

AF:

0.00

AC:

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

0.00

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

0.28

BayesDel_noAF

Pathogenic

0.16

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

Eigen

Pathogenic

0.94

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.95

D;D

M_CAP

Uncertain

0.25

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Benign

-0.73

PhyloP100

9.3

PrimateAI

Pathogenic

0.80

PROVEAN

Pathogenic

-7.5

D;D

REVEL

Pathogenic

0.73

Sift

Pathogenic

0.0

D;D

Sift4G

Pathogenic

0.0

D;D

Vest4

0.92

MVP

0.64

MPC

0.88

ClinPred

1.0

GERP RS

5.0

PromoterAI

-0.0027

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.90

gMVP

0.97

Mutation Taster

=0/100

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