21-33546281-C-T

Position:

• chr21-33546281-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_138927.4(SON):​c.146C>T​(p.Ala49Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000109 in 1,461,336 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000011 (0 hom.)
• Consequence: SON NM_138927.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.34

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]

SON (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.13157293).
• BS2: High AC in GnomAdExome4 at 16 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SON	NM_138927.4	c.146C>T	p.Ala49Val	missense_variant	2/12	ENST00000356577.10	NP_620305.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SON	ENST00000356577.10	c.146C>T	p.Ala49Val	missense_variant	2/12	1	NM_138927.4	ENSP00000348984.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000109 AC: 16 AN: 1461336 Hom.: 0 Cov.: 30 AF XY: 0.0000138 AC XY: 10 AN XY: 726982

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: 0.0000144

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

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

Sep 15, 2022

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with SON-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 49 of the SON protein (p.Ala49Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.51
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.016	T;.;.;.
Eigen	Benign	0.18
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Benign	0.75	D
LIST_S2	Uncertain	0.92	D;D;D;D
M_CAP	Benign	0.0097	T
MetaRNN	Benign	0.13	T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.90	L;.;L;L
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.2	N;N;N;N
REVEL	Benign	0.061
Sift	Uncertain	0.0080	D;D;D;D
Sift4G	Uncertain	0.0060	D;T;D;D
Polyphen		0.97	D;.;D;P
Vest4		0.32
MutPred		0.21		Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);Loss of helix (P = 0.0123);
MVP		0.15
MPC		0.24
ClinPred		0.70	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.2
Varity_R		0.11
gMVP		0.26

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs750309161; hg19: chr21-34918587;