11-6394504-A-G

Variant names:

• chr11-6394504-A-G
• rs1554935731
• NM_000543.5:c.1793A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000543.5(SMPD1):​c.1793A>G​(p.Gln598Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (no stars). Synonymous variant affecting the same amino acid position (i.e. Q598Q) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SMPD1 NM_000543.5 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 5.68
• Publications: 0 publications found

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)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000543.5
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5	c.1793A>G	p.Gln598Arg	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	c.1793A>G	p.Gln598Arg	missense_variant	Exon 6 of 6	1	NM_000543.5	ENSP00000340409.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

Niemann-Pick disease, type A Uncertain:1

Jun 09, 2017

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.49
BayesDel_addAF	Uncertain	0.088	D
BayesDel_noAF	Benign	-0.11
CADD	Benign	22
DANN	Uncertain	0.99
Eigen	Uncertain	0.27
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.73	T;T
M_CAP	Benign	0.043	D
MetaRNN	Uncertain	0.46	T;T
MetaSVM	Benign	-0.97	T
PhyloP100		5.7
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.21	N;N
REVEL	Uncertain	0.48
Sift	Benign	0.030	D;D
Sift4G	Uncertain	0.058	T;T
Vest4		0.38
MVP		0.95
MPC		0.41
ClinPred		0.64	D
GERP RS		4.2
Varity_R		0.31
gMVP		0.86
Mutation Taster		=4/96	disease causing

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

Other links and lift over

dbSNP: rs1554935731; hg19: chr11-6415734;