2-227363751-G-T

Variant names:

• chr2-227363751-G-T
• rs149462054
• NM_024795.4:c.663C>A

Variant summary

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

The NM_024795.4(TM4SF20):​c.663C>A​(p.Val221Val) 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 1,461,616 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. V221V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TM4SF20 NM_024795.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.308
• Publications: 0 publications found

Genes affected

TM4SF20 (HGNC:26230): (transmembrane 4 L six family member 20) The protein encoded by this gene is a member of the four-transmembrane L6 superfamily. Members of this family function in various cellular processes including cell proliferation, motility, and adhesion via their interactions with integrins. In human brain tissue, this gene is expressed at high levels in the parietal lobe, occipital lobe, hippocampus, pons, white matter, corpus callosum, and cerebellum. Knockout of the homologous gene in mouse results in a neurobehavioral phenotype with suggested enhanced motor coordination. A deletion mutation in the human gene is associated with specific language impairment-5. [provided by RefSeq, Jul 2016]

TM4SF20 Gene-Disease associations (from GenCC):

• specific language impairment 5

  Inheritance: AD Classification: LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae)

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=-0.51).
• BP7: Synonymous conserved (PhyloP=0.308 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_024795.4. 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
	TM4SF20	NM_024795.4	MANE Select	c.663C>A	p.Val221Val	synonymous	Exon 4 of 4	NP_079071.2	Q53R12

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TM4SF20	ENST00000304568.4	TSL:1 MANE Select	c.663C>A	p.Val221Val	synonymous	Exon 4 of 4	ENSP00000303028.3	Q53R12

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461616 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727098

African (AFR) AF: 0.00 AC: 0 AN: 33442

American (AMR) AF: 0.00 AC: 0 AN: 44666

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86210

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111922

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.51
CADD	Benign	2.3
DANN	Benign	0.80
PhyloP100		0.31
Mutation Taster		=100/0	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs149462054; hg19: chr2-228228467;