10-71829044-G-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_002778.4(PSAP):c.409C>T(p.Leu137Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,614,034 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L137V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

PSAP
NM_002778.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 2.09

Publications

1 publications found

Variant links:

Genes affected

PSAP (HGNC:9498): (prosaposin) This gene encodes a highly conserved preproprotein that is proteolytically processed to generate four main cleavage products including saposins A, B, C, and D. Each domain of the precursor protein is approximately 80 amino acid residues long with nearly identical placement of cysteine residues and glycosylation sites. Saposins A-D localize primarily to the lysosomal compartment where they facilitate the catabolism of glycosphingolipids with short oligosaccharide groups. The precursor protein exists both as a secretory protein and as an integral membrane protein and has neurotrophic activities. Mutations in this gene have been associated with Gaucher disease and metachromatic leukodystrophy. Alternative splicing results in multiple transcript variants, at least one of which encodes an isoform that is proteolytically processed. [provided by RefSeq, Feb 2016]

PSAP Gene-Disease associations (from GenCC):

combined PSAP deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, ClinGen, Labcorp Genetics (formerly Invitae)
Gaucher disease due to saposin C deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen
Krabbe disease due to saposin A deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen, G2P
metachromatic leukodystrophy due to saposin B deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen
Parkinson disease 24, autosomal dominant, susceptibility to
Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

PSAP links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
PSAP	NM_002778.4 link	c.409C>T	p.Leu137Phe	missense_variant	Exon 5 of 14	ENST00000394936.8	NP_002769.1
PSAP	NM_001042465.3 link	c.409C>T	p.Leu137Phe	missense_variant	Exon 5 of 15		NP_001035930.1
PSAP	NM_001042466.3 link	c.409C>T	p.Leu137Phe	missense_variant	Exon 5 of 15		NP_001035931.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PSAP	ENST00000394936.8 link	c.409C>T	p.Leu137Phe	missense_variant	Exon 5 of 14	1	NM_002778.4	ENSP00000378394.3

Frequencies

GnomAD3 genomes

AF:

0.0000591

AC:

AN:

152168

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000318

AC:

AN:

251334

AF XY:

0.0000442

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000528

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461866

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727236

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53398

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000153

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

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

AF:

0.0000591

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74350

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000102

Hom.:

Bravo

AF:

0.0000567

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000247

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000109

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Mar 31, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.409C>T (p.L137F) alteration is located in exon 5 (coding exon 5) of the PSAP gene. This alteration results from a C to T substitution at nucleotide position 409, causing the leucine (L) at amino acid position 137 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Sphingolipid activator protein 1 deficiency

Uncertain:1

Nov 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 137 of the PSAP protein (p.Leu137Phe). This variant is present in population databases (rs377027316, gnomAD 0.008%). This variant has not been reported in the literature in individuals affected with PSAP-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Possibly Damaging". The phenylalanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.14

BayesDel_noAF

Benign

-0.20

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.78

D;T

Eigen

Uncertain

0.48

Eigen_PC

Uncertain

0.39

FATHMM_MKL

Uncertain

0.86

LIST_S2

Benign

0.82

T;T

M_CAP

Uncertain

0.12

MetaRNN

Uncertain

0.62

D;D

MetaSVM

Uncertain

0.16

MutationAssessor

Uncertain

2.2

M;.

PhyloP100

2.1

PrimateAI

Benign

0.42

PROVEAN

Uncertain

-3.2

D;D

REVEL

Pathogenic

0.71

Sift

Benign

0.034

D;D

Sift4G

Benign

0.063

T;T

Vest4

0.38

ClinPred

0.60

GERP RS

3.1

RBP_binding_hub_radar

0.97

RBP_regulation_power_radar

2.5

Varity_R

0.40

gMVP

0.75

Mutation Taster

=67/33

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over