2-227363807-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_024795.4(TM4SF20):c.607G>T(p.Val203Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,886 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TM4SF20 NM_024795.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -4.84

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1079863).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TM4SF20	NM_024795.4	c.607G>T	p.Val203Phe	missense_variant	4/4	ENST00000304568.4
TM4SF20	XM_011511876.3	c.406G>T	p.Val136Phe	missense_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TM4SF20	ENST00000304568.4	c.607G>T	p.Val203Phe	missense_variant	4/4	1	NM_024795.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251484 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461886 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

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

Invitae

Jul 10, 2023

This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces valine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 203 of the TM4SF20 protein (p.Val203Phe). This variant has not been reported in the literature in individuals affected with TM4SF20-related conditions. ClinVar contains an entry for this variant (Variation ID: 1958344). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.62
Cadd	Benign	0.0010
Dann	Benign	0.81
DEOGEN2	Benign	0.019	T
Eigen	Benign	-1.9
Eigen_PC	Benign	-2.1
FATHMM_MKL	Benign	0.015	N
LIST_S2	Benign	0.16	T
M_CAP	Benign	0.0057	T
MetaRNN	Benign	0.11	T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	0.34	N
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-1.5	N
REVEL	Benign	0.036
Sift	Benign	0.094	T
Sift4G	Uncertain	0.044	D
Polyphen		0.45	P
Vest4		0.10
MutPred		0.46		Loss of helix (P = 0.1299);
MVP		0.076
MPC		0.0097
ClinPred		0.14	T
GERP RS		-11
Varity_R		0.073
gMVP		0.35

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

Publications

LitVar

Other links and lift over

dbSNP: rs1042631474; hg19: chr2-228228523;