21-33546255-C-A

Variant names:

• chr21-33546255-C-A
• rs1279337664
• NM_138927.4:c.120C>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_138927.4(SON):​c.120C>A​(p.Pro40Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,518 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. Synonymous variant affecting the same amino acid position (i.e. P40P) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SON NM_138927.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.233
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• ZTTK syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, ClinGen, Illumina, PanelApp Australia

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.48).
• BP7: Synonymous conserved (PhyloP=0.233 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_138927.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SON	NM_138927.4	MANE Select	c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 12	NP_620305.3	P18583-1
	SON	NM_032195.3		c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 7	NP_115571.3	P18583-3
	SON	NM_001291411.2		c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 5	NP_001278340.2	P18583-6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SON	ENST00000356577.10	TSL:1 MANE Select	c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 12	ENSP00000348984.4	P18583-1
	SON	ENST00000300278.8	TSL:1	c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 7	ENSP00000300278.2	P18583-3
	SON	ENST00000381692.6	TSL:1	c.120C>A	p.Pro40Pro	synonymous	Exon 2 of 11	ENSP00000371111.2	J3QSZ5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461518 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727064

African (AFR) AF: 0.00 AC: 0 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44660

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86200

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111824

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.48
CADD	Benign	7.6
DANN	Benign	0.60
PhyloP100		0.23

Splicing

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

Other links and lift over

dbSNP: rs1279337664; hg19: chr21-34918561;