rs779927660

Variant names:

• chr11-6392023-A-G
• rs779927660
• NM_000543.5:c.958A>G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_000543.5(SMPD1):​c.958A>G​(p.Asn320Asp) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: SMPD1 NM_000543.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 6.94

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.948
• PP5: Variant 11-6392023-A-G is Pathogenic according to our data. Variant chr11-6392023-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 556246.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5	c.958A>G	p.Asn320Asp	missense_variant	Exon 2 of 6	ENST00000342245.9	NP_000534.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD1	ENST00000342245.9	c.958A>G	p.Asn320Asp	missense_variant	Exon 2 of 6	1	NM_000543.5	ENSP00000340409.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251468 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135906

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 SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461894 Hom.: 0 Cov.: 36 AF XY: 0.00000413 AC XY: 3 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Niemann-Pick disease, type A Pathogenic:1 Uncertain:1

Jan 08, 2022

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A heterozygous missense variation in exon 2 of the SMPD1 gene that results in the amino acid substitution of Aspartate for Asparagine at codon 320 was detected. The observed variant c.958A>G (p.Asn320Asp) has not been reported in the 1000 genomes and has a MAF of 0.012% in the gnomAD databases. The in silico prediction of the variant is disease causing by DANN and MutationTaster. In summary, the variant meets our criteria to be classified as likely pathogenic. -

Jan 22, 2018

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Niemann-Pick disease, type A;C0268243:Niemann-Pick disease, type B Pathogenic:1

Apr 25, 2021

Diagnostics Division, CENTRE FOR DNA FINGERPRINTING AND DIAGNOSTICS

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

not provided Uncertain:1

Nov 08, 2017

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Pathogenic	0.19
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	.;D;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Pathogenic	1.0	D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-4.9	D;D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Vest4		0.98
MVP		0.99
MPC		0.86
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.96
gMVP		1.0

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

Other links and lift over

dbSNP: rs779927660; hg19: chr11-6413253;