10-71817368-G-T

Variant names:

• chr10-71817368-G-T
• rs541692197
• NM_002778.4:c.*73C>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_002778.4(PSAP):​c.*73C>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000749 in 1,334,800 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.5e-7 (0 hom.)
• Consequence: PSAP NM_002778.4 3_prime_UTR
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.22
• Publications: 0 publications found

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)

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.61).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PSAP	NM_002778.4	c.*73C>A		3_prime_UTR_variant	Exon 14 of 14	ENST00000394936.8	NP_002769.1
PSAP	NM_001042465.3	c.*73C>A		3_prime_UTR_variant	Exon 15 of 15		NP_001035930.1
PSAP	NM_001042466.3	c.*73C>A		3_prime_UTR_variant	Exon 15 of 15		NP_001035931.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PSAP	ENST00000394936.8	c.*73C>A		3_prime_UTR_variant	Exon 14 of 14	1	NM_002778.4	ENSP00000378394.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.49e-7 AC: 1 AN: 1334800 Hom.: 0 Cov.: 21 AF XY: 0.00000149 AC XY: 1 AN XY: 671146

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

African (AFR) AF: 0.0000324 AC: 1 AN: 30822

American (AMR) AF: 0.00 AC: 0 AN: 44584

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25346

East Asian (EAS) AF: 0.00 AC: 0 AN: 39092

South Asian (SAS) AF: 0.00 AC: 0 AN: 83774

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53172

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5536

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 996278

Other (OTH) AF: 0.00 AC: 0 AN: 56196

⚠️ 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.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.61
CADD	Benign	7.2
DANN	Benign	0.80
PhyloP100		1.2

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: rs541692197; hg19: chr10-73577125;