21-33543145-G-T

Position:

• chr21-33543145-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_138927.4(SON):​c.53G>T​(p.Arg18Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,852 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SON NM_138927.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.08

Genes affected

SON (HGNC:11183): (SON DNA and RNA binding protein) This gene encodes a protein that contains multiple simple repeats. The encoded protein binds RNA and promotes pre-mRNA splicing, particularly of transcripts with poor splice sites. The protein also recognizes a specific DNA sequence found in the human hepatitis B virus (HBV) and represses HBV core promoter activity. There is a pseudogene for this gene on chromosome 1. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

GART (HGNC:4163): (phosphoribosylglycinamide formyltransferase, phosphoribosylglycinamide synthetase, phosphoribosylaminoimidazole synthetase) The protein encoded by this gene is a trifunctional polypeptide. It has phosphoribosylglycinamide formyltransferase, phosphoribosylglycinamide synthetase, phosphoribosylaminoimidazole synthetase activity which is required for de novo purine biosynthesis. This enzyme is highly conserved in vertebrates. Alternative splicing of this gene results in two transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SON	NM_138927.4	c.53G>T	p.Arg18Leu	missense_variant	1/12	ENST00000356577.10	NP_620305.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SON	ENST00000356577.10	c.53G>T	p.Arg18Leu	missense_variant	1/12	1	NM_138927.4	ENSP00000348984	P3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461852 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727224

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 05, 2023

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 18 of the SON protein (p.Arg18Leu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SON-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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	Pathogenic	0.93
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.047	T;.;.;.
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Benign	0.27	N
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Benign	0.027	D
MetaRNN	Uncertain	0.56	D;D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.81	L;.;L;L
MutationTaster	Benign	0.58	D;N;N;N;N
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-2.1	N;D;N;N
REVEL	Benign	0.19
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		0.97	D;.;D;D
Vest4		0.62
MutPred		0.36		Loss of MoRF binding (P = 0.0032);Loss of MoRF binding (P = 0.0032);Loss of MoRF binding (P = 0.0032);Loss of MoRF binding (P = 0.0032);
MVP		0.70
MPC		0.19
ClinPred		0.74	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.53
gMVP		0.87

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs967177354; hg19: chr21-34915451;