16-2496641-G-T

Position:

• chr16-2496641-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_001199107.2(TBC1D24):​c.493G>T​(p.Gly165Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,056 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 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: 6.8e-7 (0 hom.)
• Consequence: TBC1D24 NM_001199107.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.11

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 2 ACMG points.

• PM1: In a domain Rab-GAP TBC (size 215) in uniprot entity TBC24_HUMAN there are 17 pathogenic changes around while only 3 benign (85%) in NM_001199107.2
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.12454003).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TBC1D24	NM_001199107.2	c.493G>T	p.Gly165Cys	missense_variant	2/8	ENST00000646147.1	NP_001186036.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TBC1D24	ENST00000646147.1	c.493G>T	p.Gly165Cys	missense_variant	2/8		NM_001199107.2	ENSP00000494678.1
ENSG00000260272	ENST00000564543.1	c.493G>T	p.Gly165Cys	missense_variant	1/3	2		ENSP00000455547.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460056 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726412

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Aug 16, 2023

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. 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. This variant has not been reported in the literature in individuals affected with TBC1D24-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 165 of the TBC1D24 protein (p.Gly165Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.58
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Benign	0.11	.;T;T;.;.;.;.
Eigen	Benign	-0.56
Eigen_PC	Benign	-0.75
FATHMM_MKL	Benign	0.10	N
LIST_S2	Uncertain	0.92	.;.;D;D;D;D;D
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.12	T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.8	L;L;L;.;.;L;.
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-1.9	N;.;N;.;.;.;N
REVEL	Benign	0.041
Sift	Benign	0.042	D;.;D;.;.;.;D
Sift4G	Uncertain	0.025	D;.;D;.;.;D;D
Polyphen		0.83	P;P;P;.;.;P;.
Vest4		0.20
MutPred		0.35		Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);Gain of catalytic residue at P164 (P = 0.008);
MVP		0.54
MPC		1.0, 1.4
ClinPred		0.56	D
GERP RS		-1.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.3
Varity_R		0.11
gMVP		0.43

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: rs200926225; hg19: chr16-2546642;