chr11-6390912-TG-CT

Variant names:

• chr11-6390912-TG-CT
• NM_000543.5:c.314_315delTGinsCT
• SMPD1 p.Leu105Pro

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PS1_Very_Strong

The NM_000543.5(SMPD1):​c.314_315delTGinsCT​(p.Leu105Pro) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Synonymous variant affecting the same amino acid position (i.e. L105L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SMPD1 NM_000543.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.97
• 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: Orphanet, G2P, PanelApp Australia, Genomics England PanelApp
• Niemann-Pick disease type B

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PS1: Transcript NM_000543.5 (SMPD1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPD1	NM_000543.5	MANE Select	c.314_315delTGinsCT	p.Leu105Pro	missense	N/A	NP_000534.3
	SMPD1	NM_001007593.3		c.314_315delTGinsCT	p.Leu105Pro	missense	N/A	NP_001007594.2	P17405-4
	SMPD1	NM_001365135.2		c.314_315delTGinsCT	p.Leu105Pro	missense	N/A	NP_001352064.1	P17405-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPD1	ENST00000342245.9	TSL:1 MANE Select	c.314_315delTGinsCT	p.Leu105Pro	missense	N/A	ENSP00000340409.4	P17405-1
	SMPD1	ENST00000531303.5	TSL:1	n.314_315delTGinsCT		non_coding_transcript_exon	Exon 1 of 6	ENSP00000432625.1	E9PPK6
	SMPD1	ENST00000533123.5	TSL:1	n.314_315delTGinsCT		non_coding_transcript_exon	Exon 1 of 5	ENSP00000435950.1	G3V1E1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		6.0

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr11-6412142;