Genetic Variant SMPD4:p.Lys823Arg (chr2-130152571-T-C) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_017951.5(SMPD4):c.2468A>G(p.Lys823Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000129 in 1,547,448 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000013 ( 0 hom. )

Consequence

SMPD4
NM_017951.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.24

Publications

0 publications found

Variant links:

Genes affected

SMPD4 (HGNC:32949): (sphingomyelin phosphodiesterase 4) The protein encoded by this gene is a sphingomyelinase that catalyzes the hydrolysis of membrane sphingomyelin to form phosphorylcholine and ceramide. This gene is activated by DNA damage, cellular stress, and tumor necrosis factor, but it is downregulated by wild-type p53. The encoded protein localizes to the endoplasmic reticulum and Golgi network. [provided by RefSeq, Mar 2017]

SMPD4 Gene-Disease associations (from GenCC):

neurodevelopmental disorder with microcephaly, arthrogryposis, and structural brain anomalies
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P

SMPD4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.13414887).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD4	NM_017951.5 link	c.2468A>G	p.Lys823Arg	missense_variant	Exon 20 of 20	ENST00000680298.1	NP_060421.3	Q9NXE4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD4	ENST00000680298.1 link	c.2468A>G	p.Lys823Arg	missense_variant	Exon 20 of 20		NM_017951.5	ENSP00000506463.1		A0A7P0TB24

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152210

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:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000256

AC:

AN:

156164

AF XY:

0.0000365

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000129

AC:

AN:

1395120

Hom.:

Cov.:

AF XY:

0.0000189

AC XY:

AN XY:

687702

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31518

American (AMR)

AF:

0.0000280

AC:

AN:

35658

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25148

East Asian (EAS)

AF:

0.00

AC:

AN:

35684

South Asian (SAS)

AF:

0.000190

AC:

AN:

79140

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4538

European-Non Finnish (NFE)

AF:

9.28e-7

AC:

AN:

1077072

Other (OTH)

AF:

0.0000173

AC:

AN:

57756

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152328

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74494

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41576

American (AMR)

AF:

0.00

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.000414

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2112

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Feb 07, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.2585A>G (p.K862R) alteration is located in exon 20 (coding exon 20) of the SMPD4 gene. This alteration results from a A to G substitution at nucleotide position 2585, causing the lysine (K) at amino acid position 862 to be replaced by an arginine (R). 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

0.084

BayesDel_addAF

Benign

-0.33

BayesDel_noAF

Benign

-0.47

CADD

Benign

(source)

DANN

Uncertain

1.0

Eigen

Benign

-0.0069

Eigen_PC

Benign

-0.052

FATHMM_MKL

Uncertain

0.84

LIST_S2

Benign

0.80

T;T;T

M_CAP

Benign

0.011

MetaRNN

Benign

0.13

T;T;T

MetaSVM

Benign

-0.72

PhyloP100

3.2

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-1.1

N;N;N

REVEL

Benign

0.14

Sift

Benign

0.10

T;T;T

Sift4G

Benign

0.16

T;T;T

Vest4

0.070

MVP

0.50

MPC

0.69

ClinPred

0.36

GERP RS

2.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.8

Varity_R

0.095

gMVP

0.36

Mutation Taster

=87/13

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

Publications

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chr2-130152571-T-C

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over