Genetic Variant SPPL3:p.Gly321Arg (chr12-120767406-C-T) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_139015.5(SPPL3):c.961G>A(p.Gly321Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,404 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SPPL3
NM_139015.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.48

Publications

0 publications found

Variant links:

Genes affected

SPPL3 (HGNC:30424): (signal peptide peptidase like 3) Enables aspartic endopeptidase activity, intramembrane cleaving and protein homodimerization activity. Involved in several processes, including T cell receptor signaling pathway; positive regulation of calcineurin-NFAT signaling cascade; and positive regulation of protein dephosphorylation. Located in Golgi-associated vesicle membrane; plasma membrane; and rough endoplasmic reticulum. Is integral component of cytoplasmic side of endoplasmic reticulum membrane and integral component of lumenal side of endoplasmic reticulum membrane. [provided by Alliance of Genome Resources, Apr 2022]

SPPL3 links:

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ACMG classification

Classification was made for transcript

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

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.917

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SPPL3	NM_139015.5 link	c.961G>A	p.Gly321Arg	missense_variant	Exon 9 of 11	ENST00000353487.7	NP_620584.2	Q8TCT6-2Q9UG23
SPPL3	XM_011537925.3 link	c.961G>A	p.Gly321Arg	missense_variant	Exon 9 of 11		XP_011536227.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
SPPL3	ENST00000353487.7 link	c.961G>A	p.Gly321Arg	missense_variant	Exon 9 of 11	1	NM_139015.5	ENSP00000288680.4	Q8TCT6-2
SPPL3	ENST00000545209.1 link	n.495G>A		non_coding_transcript_exon_variant	Exon 2 of 4	1
SPPL3	ENST00000392495.7 link	n.1537G>A		non_coding_transcript_exon_variant	Exon 3 of 5	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460404

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726512

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:

33448

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86208

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52984

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4948

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111976

Other (OTH)

AF:

0.00

AC:

AN:

60284

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

May 28, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.961G>A (p.G321R) alteration is located in exon 9 (coding exon 9) of the SPPL3 gene. This alteration results from a G to A substitution at nucleotide position 961, causing the glycine (G) at amino acid position 321 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.29

BayesDel_noAF

Pathogenic

0.17

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

Eigen

Pathogenic

0.99

Eigen_PC

Pathogenic

0.93

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

M_CAP

Benign

0.078

MetaRNN

Pathogenic

0.92

MetaSVM

Benign

-0.53

PhyloP100

7.5

PrimateAI

Pathogenic

0.96

PROVEAN

Pathogenic

-6.4

REVEL

Pathogenic

0.75

Sift

Pathogenic

0.0

Sift4G

Uncertain

0.0020

Vest4

0.97

MVP

0.50

MPC

2.4

ClinPred

1.0

GERP RS

5.7

Varity_R

0.92

gMVP

0.99

Mutation Taster

=11/89

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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chr12-120767406-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over