1-1535454-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP3 BS2

The NM_001114748.2(TMEM240):c.427C>T(p.Arg143Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00002 in 1,549,004 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R143Q) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000021 (0 hom.)
• Consequence: TMEM240 NM_001114748.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.16

Genes affected

TMEM240 (HGNC:25186): (transmembrane protein 240) This gene encodes a transmembrane-domain containing protein found in the brain and cerebellum. Mutations in this gene result in spinocerebellar ataxia 21. [provided by RefSeq, Dec 2014]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.834
• BS2: High AC in GnomAdExome at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM240	NM_001114748.2	c.427C>T	p.Arg143Trp	missense_variant	4/4	ENST00000378733.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM240	ENST00000378733.9	c.427C>T	p.Arg143Trp	missense_variant	4/4	2	NM_001114748.2	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152124 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000343 AC: 5 AN: 145976 Hom.: 0 AF XY: 0.0000384 AC XY: 3 AN XY: 78104

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000409

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: 0.0000573

Gnomad OTH exome AF: 0.000240

GnomAD4 exome AF: 0.0000208 AC: 29 AN: 1396880 Hom.: 0 Cov.: 33 AF XY: 0.0000232 AC XY: 16 AN XY: 688972

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000281

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: 0.0000241

Gnomad4 OTH exome AF: 0.0000345

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152124 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74312

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000302

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 08, 2022

The c.427C>T (p.R143W) alteration is located in exon 4 (coding exon 4) of the TMEM240 gene. This alteration results from a C to T substitution at nucleotide position 427, causing the arginine (R) at amino acid position 143 to be replaced by a tryptophan (W). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 22, 2023

This variant has not been reported in the literature in individuals affected with TMEM240-related conditions. 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. 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 2403158). This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 143 of the TMEM240 protein (p.Arg143Trp). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.27
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D;D
Eigen	Benign	0.092
Eigen_PC	Benign	0.053
FATHMM_MKL	Uncertain	0.90	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.83	D;D
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	0.81	L;L
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-5.3	D;D
REVEL	Benign	0.19
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.99	D;D
Vest4		0.65
MutPred		0.37		Loss of disorder (P = 0.0085);Loss of disorder (P = 0.0085);
MVP		0.39
ClinPred		0.47	T
GERP RS		1.6
Varity_R		0.41
gMVP		0.75

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: rs1026446550; hg19: chr1-1470834;