16-2500855-G-A

Position:

• chr16-2500855-G-A

Variant summary

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

The NM_001199107.2(TBC1D24):​c.1577G>A​(p.Arg526His) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TBC1D24 NM_001199107.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.83

Genes affected

TBC1D24 (HGNC:29203): (TBC1 domain family member 24) This gene encodes a protein with a conserved domain, referred to as the TBC domain, characteristic of proteins which interact with GTPases. TBC domain proteins may serve as GTPase-activating proteins for a particular group of GTPases, the Rab (Ras-related proteins in brain) small GTPases which are involved in the regulation of membrane trafficking. Mutations in this gene are associated with familial infantile myoclonic epilepsy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2011]

ENSG00000260272 (HGNC:):

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=0.24618295).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TBC1D24	NM_001199107.2	c.1577G>A	p.Arg526His	missense_variant	8/8	ENST00000646147.1	NP_001186036.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TBC1D24	ENST00000646147.1	c.1577G>A	p.Arg526His	missense_variant	8/8		NM_001199107.2	ENSP00000494678.1
ENSG00000260272	ENST00000564543.1	c.965+3742G>A		intron_variant		2		ENSP00000455547.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000411 AC: 1 AN: 243024 Hom.: 0 AF XY: 0.00000753 AC XY: 1 AN XY: 132722

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.00000896

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000274 AC: 4 AN: 1457368 Hom.: 0 Cov.: 31 AF XY: 0.00000276 AC XY: 2 AN XY: 725256

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 14, 2019

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge -

Developmental and epileptic encephalopathy, 1;C3892048:Autosomal dominant nonsyndromic hearing loss 65;CN236805:Caused by mutation in the TBC1 domain family, member 24 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 18, 2023

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 526 of the TBC1D24 protein (p.Arg526His). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with TBC1D24-related conditions. ClinVar contains an entry for this variant (Variation ID: 474305). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TBC1D24 protein function with a negative predictive value of 80%. 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	0.071
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.45
CADD	Uncertain	24
DANN	Benign	0.95
DEOGEN2	Benign	0.022	.;T;T;.
Eigen	Benign	0.0070
Eigen_PC	Benign	0.098
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.87	.;.;D;D
M_CAP	Benign	0.014	T
MetaRNN	Benign	0.25	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.3	.;L;L;.
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-2.0	N;.;N;.
REVEL	Benign	0.059
Sift	Benign	0.090	T;.;T;.
Sift4G	Benign	0.43	T;.;T;T
Polyphen		0.46	P;P;P;P
Vest4		0.13
MutPred		0.56		.;Loss of methylation at R526 (P = 0.0471);Loss of methylation at R526 (P = 0.0471);.;
MVP		0.74
MPC		0.44
ClinPred		0.43	T
GERP RS		3.6
Varity_R		0.17
gMVP		0.51

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: rs752301570; hg19: chr16-2550856;