rs868423827

Variant names:

• chr11-6390839-C-T
• rs868423827
• NM_000543.5:c.241C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000543.5(SMPD1):​c.241C>T​(p.Arg81*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,614,012 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 Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SMPD1 NM_000543.5 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -0.0410
• 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: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-6390839-C-T is Pathogenic according to our data. Variant chr11-6390839-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 370753.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000543.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPD1	NM_000543.5	MANE Select	c.241C>T	p.Arg81*	stop_gained	Exon 1 of 6	NP_000534.3
	SMPD1	NM_001318088.2		c.-721C>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 6	NP_001305017.1
	SMPD1	NM_001007593.3		c.241C>T	p.Arg81*	stop_gained	Exon 1 of 6	NP_001007594.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPD1	ENST00000342245.9	TSL:1 MANE Select	c.241C>T	p.Arg81*	stop_gained	Exon 1 of 6	ENSP00000340409.4
	SMPD1	ENST00000531303.5	TSL:1	n.241C>T		non_coding_transcript_exon	Exon 1 of 6	ENSP00000432625.1
	SMPD1	ENST00000533123.5	TSL:1	n.241C>T		non_coding_transcript_exon	Exon 1 of 5	ENSP00000435950.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152120 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461892 Hom.: 0 Cov.: 38 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112012

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152120 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74326

African (AFR) AF: 0.0000241 AC: 1 AN: 41420

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68002

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000406 Hom.: 0

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Niemann-Pick disease, type A (2)
1	-	-	Niemann-Pick disease, type A;C0268243:Niemann-Pick disease, type B (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Benign	0.18
Eigen_PC	Benign	-0.11
FATHMM_MKL	Benign	0.11	N
PhyloP100		-0.041
Vest4		0.79
GERP RS		3.3
PromoterAI		-0.10	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Mutation Taster		=1/199	disease causing (ClinVar)

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: rs868423827; hg19: chr11-6412069;