22-30342861-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_005877.6(SF3A1):c.670G>T(p.Gly224Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,328 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SF3A1 NM_005877.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.55

Genes affected

SF3A1 (HGNC:10765): (splicing factor 3a subunit 1) This gene encodes a subunit of the splicing factor 3a protein complex. The splicing factor 3a heterotrimer is a component of the mature U2 small nuclear ribonucleoprotein particle (snRNP). U2 small nuclear ribonucleoproteins play a critical role in spliceosome assembly and pre-mRNA splicing. [provided by RefSeq, Aug 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, SF3A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.755

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SF3A1	NM_005877.6	c.670G>T	p.Gly224Cys	missense_variant	5/16	ENST00000215793.13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SF3A1	ENST00000215793.13	c.670G>T	p.Gly224Cys	missense_variant	5/16	1	NM_005877.6	P1
SF3A1	ENST00000471037.1	n.241G>T		non_coding_transcript_exon_variant	2/2	3
SF3A1	ENST00000411423.1	c.64-3682G>T		intron_variant, NMD_transcript_variant		4
SF3A1	ENST00000447376.1	c.*12G>T		3_prime_UTR_variant, NMD_transcript_variant	3/4	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460328 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726668

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 17, 2021

The c.670G>T (p.G224C) alteration is located in exon 5 (coding exon 5) of the SF3A1 gene. This alteration results from a G to T substitution at nucleotide position 670, causing the glycine (G) at amino acid position 224 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.10
Cadd	Pathogenic	29
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.44	T
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D
M_CAP	Benign	0.039	D
MetaRNN	Pathogenic	0.76	D
MetaSVM	Benign	-0.68	T
MutationAssessor	Benign	1.9	L
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-2.7	D
REVEL	Uncertain	0.37
Sift	Uncertain	0.0060	D
Sift4G	Uncertain	0.018	D
Polyphen		1.0	D
Vest4		0.78
MutPred		0.49		Loss of disorder (P = 0.0544);
MVP		0.64
MPC		2.0
ClinPred		0.97	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.56
gMVP		0.54

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1234027070; hg19: chr22-30738850;