Genetic Variant SMPD3:p.Ala335Thr (chr16-68371179-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_018667.4(SMPD3):c.1003G>A(p.Ala335Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,460,420 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

SMPD3
NM_018667.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.425

Variant links:

Genes affected

SMPD3 (HGNC:14240): (sphingomyelin phosphodiesterase 3) Predicted to enable phosphatidic acid binding activity; phosphatidylserine binding activity; and sphingomyelin phosphodiesterase activity. Predicted to be involved in positive regulation of exosomal secretion and sphingomyelin metabolic process. Predicted to act upstream of or within several processes, including animal organ development; enzyme linked receptor protein signaling pathway; and sphingolipid metabolic process. Predicted to be located in Golgi apparatus and plasma membrane. Predicted to be active in cytoplasm. Biomarker of pulmonary emphysema. [provided by Alliance of Genome Resources, Apr 2022]

SMPD3 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.061388016).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD3	NM_018667.4 link	c.1003G>A	p.Ala335Thr	missense_variant	Exon 3 of 9	ENST00000219334.10	NP_061137.1	Q9NY59-1A8K0T6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD3	ENST00000219334.10 link	c.1003G>A	p.Ala335Thr	missense_variant	Exon 3 of 9	1	NM_018667.4	ENSP00000219334.5		Q9NY59-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000160

AC:

AN:

249914

Hom.:

AF XY:

0.00000739

AC XY:

AN XY:

135294

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000869

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000477

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1460420

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726558

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000895

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.0000191

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000756

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jul 20, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1003G>A (p.A335T) alteration is located in exon 3 (coding exon 1) of the SMPD3 gene. This alteration results from a G to A substitution at nucleotide position 1003, causing the alanine (A) at amino acid position 335 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.065

BayesDel_addAF

Benign

-0.43

BayesDel_noAF

Benign

-0.66

CADD

Benign

0.71

DANN

Benign

0.89

DEOGEN2

Benign

0.10

T;T;.

Eigen

Benign

-1.0

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.18

LIST_S2

Benign

0.54

T;T;T

M_CAP

Benign

0.0028

MetaRNN

Benign

0.061

T;T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.4

L;.;L

PrimateAI

Benign

0.39

PROVEAN

Benign

-0.24

N;N;N

REVEL

Benign

0.021

Sift

Benign

0.36

T;T;T

Sift4G

Benign

0.18

T;T;T

Polyphen

0.0

B;.;.

Vest4

0.080

MutPred

0.42

Gain of glycosylation at A335 (P = 0.0131);Gain of glycosylation at A335 (P = 0.0131);Gain of glycosylation at A335 (P = 0.0131);

MVP

0.12

MPC

0.20

ClinPred

0.050

GERP RS

0.23

Varity_R

0.032

gMVP

0.39

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over