16-29664115-C-G

Position:

• chr16-29664115-C-G

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6 BP7

The NM_003123.6(SPN):​c.387C>G​(p.Thr129=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00088 in 1,614,120 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (no stars).

• Frequency:
  • Genomes: 𝑓 0.00068 (0 hom., cov: 31)
  • Exomes 𝑓: 0.00090 (1 hom.)
• Consequence: SPN NM_003123.6 synonymous
• Clinical Significance: Likely benign no assertion criteria provided B:1
• Conservation: PhyloP100: -0.164

Genes affected

SPN (HGNC:11249): (sialophorin) This gene encodes a highly sialylated glycoprotein that functions in antigen-specific activation of T cells, and is found on the surface of thymocytes, T lymphocytes, monocytes, granulocytes, and some B lymphocytes. It contains a mucin-like extracellular domain, a transmembrane region and a carboxy-terminal intracellular region. The extracellular domain has a high proportion of serine and threonine residues, allowing extensive O-glycosylation, and has one potential N-glycosylation site, while the carboxy-terminal region has potential phosphorylation sites that may mediate transduction of activation signals. Different glycoforms of this protein have been described. In stimulated immune cells, proteolytic cleavage of the extracellular domain occurs in some cell types, releasing a soluble extracellular fragment. Defects in expression of this gene are associated with Wiskott-Aldrich syndrome. [provided by RefSeq, Sep 2017]

QPRT (HGNC:9755): (quinolinate phosphoribosyltransferase) This gene encodes a key enzyme in catabolism of quinolinate, an intermediate in the tryptophan-nicotinamide adenine dinucleotide pathway. Quinolinate acts as a most potent endogenous exitotoxin to neurons. Elevation of quinolinate levels in the brain has been linked to the pathogenesis of neurodegenerative disorders such as epilepsy, Alzheimer's disease, and Huntington's disease. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.66).
• BP6: Variant 16-29664115-C-G is Benign according to our data. Variant chr16-29664115-C-G is described in ClinVar as [Likely_benign]. Clinvar id is 3042826.Status of the report is no_assertion_criteria_provided, 0 stars.
• BP7: Synonymous conserved (PhyloP=-0.164 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPN	NM_003123.6	c.387C>G	p.Thr129=	synonymous_variant	2/2	ENST00000652691.1	NP_003114.1
SPN	NM_001030288.4	c.387C>G	p.Thr129=	synonymous_variant	2/2		NP_001025459.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPN	ENST00000652691.1	c.387C>G	p.Thr129=	synonymous_variant	2/2		NM_003123.6	ENSP00000498852	P1

Frequencies

GnomAD3 genomes AF: 0.000684 AC: 104 AN: 152110 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.000266

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000262

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.000282

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00125

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.000577 AC: 145 AN: 251478 Hom.: 0 AF XY: 0.000530 AC XY: 72 AN XY: 135918

Gnomad AFR exome AF: 0.000246

Gnomad AMR exome AF: 0.000260

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.000416

Gnomad NFE exome AF: 0.00103

Gnomad OTH exome AF: 0.000978

GnomAD4 exome AF: 0.000901 AC: 1317 AN: 1461894 Hom.: 1 Cov.: 31 AF XY: 0.000850 AC XY: 618 AN XY: 727248

Gnomad4 AFR exome AF: 0.000209

Gnomad4 AMR exome AF: 0.000313

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.000412

Gnomad4 NFE exome AF: 0.00108

Gnomad4 OTH exome AF: 0.00114

GnomAD4 genome AF: 0.000683 AC: 104 AN: 152226 Hom.: 0 Cov.: 31 AF XY: 0.000591 AC XY: 44 AN XY: 74436

Gnomad4 AFR AF: 0.000265

Gnomad4 AMR AF: 0.000262

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.000282

Gnomad4 NFE AF: 0.00125

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.000682 Hom.: 0

Bravo AF: 0.000536

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.00104

EpiControl AF: 0.000652

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: no assertion criteria provided

Submissions by phenotype

SPN-related disorder Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 20, 2023

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.66
CADD	Benign	1.1
DANN	Benign	0.39

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

LitVar

Other links and lift over

dbSNP: rs139180392; hg19: chr16-29675436;