17-18340819-G-C

Position:

• chr17-18340819-G-C

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The NM_004169.5(SHMT1):​c.520-6C>G variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000856 in 1,611,588 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.00047 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000046 (0 hom.)
• Consequence: SHMT1 NM_004169.5 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.04827
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.235

Genes affected

SHMT1 (HGNC:10850): (serine hydroxymethyltransferase 1) This gene encodes the cytosolic form of serine hydroxymethyltransferase, a pyridoxal phosphate-containing enzyme that catalyzes the reversible conversion of serine and tetrahydrofolate to glycine and 5,10-methylene tetrahydrofolate. This reaction provides one-carbon units for synthesis of methionine, thymidylate, and purines in the cytoplasm. This gene is located within the Smith-Magenis syndrome region on chromosome 17. A pseudogene of this gene is located on the short arm of chromosome 1. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2013]

MIR6778 (HGNC:50183): (microRNA 6778) microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BP6: Variant 17-18340819-G-C is Benign according to our data. Variant chr17-18340819-G-C is described in ClinVar as [Likely_benign]. Clinvar id is 740690.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SHMT1	NM_004169.5	c.520-6C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000316694.8	NP_004160.3
MIR6778	NR_106836.1	n.68C>G		non_coding_transcript_exon_variant	1/1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SHMT1	ENST00000316694.8	c.520-6C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_004169.5	ENSP00000318868	P1
MIR6778	ENST00000617912.1	n.68C>G		mature_miRNA_variant	1/1

Frequencies

GnomAD3 genomes AF: 0.000467 AC: 71 AN: 152196 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00154

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00143

GnomAD3 exomes AF: 0.000126 AC: 31 AN: 246908 Hom.: 0 AF XY: 0.0000748 AC XY: 10 AN XY: 133620

Gnomad AFR exome AF: 0.00165

Gnomad AMR exome AF: 0.0000876

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000335

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000166

GnomAD4 exome AF: 0.0000459 AC: 67 AN: 1459274 Hom.: 0 Cov.: 30 AF XY: 0.0000289 AC XY: 21 AN XY: 725732

Gnomad4 AFR exome AF: 0.00162

Gnomad4 AMR exome AF: 0.000112

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000117

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.000116

GnomAD4 genome AF: 0.000466 AC: 71 AN: 152314 Hom.: 0 Cov.: 32 AF XY: 0.000336 AC XY: 25 AN XY: 74490

Gnomad4 AFR AF: 0.00154

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00142

Alfa AF: 0.000260 Hom.: 0

Bravo AF: 0.000536

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 16, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	8.1
DANN	Benign	0.31

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.048
dbscSNV1_RF	Benign	0.32
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: rs377036954; hg19: chr17-18244133;