rs758299397

chr16-2496735-A-G

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.587A>G(p.Lys196Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,512 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 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: 0.0000014 (0 hom.)
• Consequence: TBC1D24 NM_001199107.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.48

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]

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 39 pathogenic changes around while only 10 benign (80%) in NM_001199107.2
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.15778527).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TBC1D24	NM_001199107.2	c.587A>G	p.Lys196Arg	missense_variant	2/8	ENST00000646147.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TBC1D24	ENST00000646147.1	c.587A>G	p.Lys196Arg	missense_variant	2/8		NM_001199107.2	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249142 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135264

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

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: 1461512 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727066

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.00000825 AC: 1

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

Invitae

May 22, 2023

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. 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. ClinVar contains an entry for this variant (Variation ID: 541319). This variant has not been reported in the literature in individuals affected with TBC1D24-related conditions. This variant is present in population databases (rs758299397, gnomAD 0.003%). This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 196 of the TBC1D24 protein (p.Lys196Arg). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.35	T
BayesDel_noAF	Benign	-0.65
Cadd	Benign	19
Dann	Uncertain	0.99
Eigen	Benign	-0.18
Eigen_PC	Benign	-0.042
FATHMM_MKL	Uncertain	0.87	D
M_CAP	Benign	0.016	T
MetaRNN	Benign	0.16	T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.1	L;L;L;.;.;L;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-0.89	N;.;N;.;.;.;N
Sift	Benign	0.30	T;.;T;.;.;.;T
Sift4G	Benign	0.17	T;.;T;.;.;T;T
Polyphen		0.019	B;B;B;.;.;B;.
Vest4		0.18
MutPred		0.59		Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);Loss of ubiquitination at K196 (P = 0.0174);
MVP		0.66
MPC		0.31, 0.50
ClinPred		0.26	T
GERP RS		2.8
Varity_R		0.12
gMVP		0.24

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: rs758299397; hg19: chr16-2546736;