21-33559579-T-A

Variant summary

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

The NM_138927.4(SON):c.6469-8T>A variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SON NM_138927.4 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.02100
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.91

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]

DONSON (HGNC:2993): (DNA replication fork stabilization factor DONSON) This gene lies downstream of the SON gene and spans 10 kb on chromosome 21. The function of this gene is unknown. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.78).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SON	NM_138927.4	c.6469-8T>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000356577.10
SON	NM_001291412.3	c.553-8T>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant
SON	NM_032195.3	c.6469-8T>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant
SON	NR_103797.2	n.6524-8T>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SON	ENST00000356577.10	c.6469-8T>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_138927.4	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000546

EpiControl AF: 0.00

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

GeneDx

Oct 30, 2019

Not observed in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge; In-silico analysis, which includes splice predictors and evolutionary conservation, is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.78
Cadd	Benign	9.3
Dann	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.021
dbscSNV1_RF	Benign	0.15

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr21-34931885;