Genetic Variant NM_000543.5:c.130_147delGCGCTGGCGCTGGCTCTG (chr11-6390724-GCTGGCGCTGGCGCTGGCT-G) – ACMG Classification: Uncertain_significance (1 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM1BP3

The NM_000543.5(SMPD1):c.130_147delGCGCTGGCGCTGGCTCTG(p.Ala44_Leu49del) variant causes a conservative inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000021 in 1,426,694 control chromosomes in the GnomAD database, with no homozygous occurrence. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, 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. Synonymous variant affecting the same amino acid position (i.e. A44A) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

SMPD1
NM_000543.5 conservative_inframe_deletion

Scores

Not classified

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.48

Publications

0 publications found

Variant links:

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)

SMPD1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 8 uncertain in NM_000543.5

BP3

Nonframeshift variant in repetitive region in NM_000543.5

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMPD1	NM_000543.5 link	c.130_147delGCGCTGGCGCTGGCTCTG	p.Ala44_Leu49del	conservative_inframe_deletion	Exon 1 of 6	ENST00000342245.9	NP_000534.3	P17405-1Q59EN6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMPD1	ENST00000342245.9 link	c.130_147delGCGCTGGCGCTGGCTCTG	p.Ala44_Leu49del	conservative_inframe_deletion	Exon 1 of 6	1	NM_000543.5	ENSP00000340409.4		P17405-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000412

AC:

AN:

242922

AF XY:

0.00000755

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:

0.0000471

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000210

AC:

AN:

1426694

Hom.:

AF XY:

0.00000141

AC XY:

AN XY:

708184

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

30394

American (AMR)

AF:

0.00

AC:

AN:

42518

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25350

East Asian (EAS)

AF:

0.00

AC:

AN:

38484

South Asian (SAS)

AF:

0.00

AC:

AN:

79626

European-Finnish (FIN)

AF:

0.0000194

AC:

AN:

51574

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5588

European-Non Finnish (NFE)

AF:

0.00000183

AC:

AN:

1094466

Other (OTH)

AF:

0.00

AC:

AN:

58694

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.342

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.5

Splicing

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over