chr16-2496034-G-T

Variant names:

• chr16-2496034-G-T
• rs1280271387
• NM_001199107.2:c.-115G>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001199107.2(TBC1D24):​c.-115G>T variant causes a splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000228 in 1,315,506 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000017 (0 hom.)
• Consequence: TBC1D24 NM_001199107.2 splice_region
• Scores: Splicing: ADA: 0.02401
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.668
• Publications: 0 publications found

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]

TBC1D24 Gene-Disease associations (from GenCC):

• DOORS syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet, PanelApp Australia, G2P
• familial infantile myoclonic epilepsy

  Inheritance: AR Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet
• autosomal dominant nonsyndromic hearing loss 65

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• malignant migrating partial seizures of infancy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• focal epilepsy-intellectual disability-cerebro-cerebellar malformation

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hearing loss, autosomal recessive

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• progressive myoclonic epilepsy with dystonia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• nonsyndromic genetic hearing loss

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• autosomal recessive nonsyndromic hearing loss 86

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ENSG00000260272 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TBC1D24	NM_001199107.2	c.-115G>T		splice_region_variant	Exon 2 of 8	ENST00000646147.1	NP_001186036.1
TBC1D24	NM_001199107.2	c.-115G>T		5_prime_UTR_variant	Exon 2 of 8	ENST00000646147.1	NP_001186036.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TBC1D24	ENST00000646147.1	c.-115G>T		splice_region_variant	Exon 2 of 8		NM_001199107.2	ENSP00000494678.1
TBC1D24	ENST00000646147.1	c.-115G>T		5_prime_UTR_variant	Exon 2 of 8		NM_001199107.2	ENSP00000494678.1
ENSG00000260272	ENST00000564543.1	c.-115G>T		5_prime_UTR_variant	Exon 1 of 3	2		ENSP00000455547.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152188 Hom.: 0 Cov.: 33

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000172 AC: 2 AN: 1163318 Hom.: 0 Cov.: 16 AF XY: 0.00 AC XY: 0 AN XY: 582418

African (AFR) AF: 0.00 AC: 0 AN: 25940

American (AMR) AF: 0.00 AC: 0 AN: 32834

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 21088

East Asian (EAS) AF: 0.00 AC: 0 AN: 37686

South Asian (SAS) AF: 0.00 AC: 0 AN: 73134

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49926

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4136

European-Non Finnish (NFE) AF: 0.00000230 AC: 2 AN: 868982

Other (OTH) AF: 0.00 AC: 0 AN: 49592

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152188 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74342

African (AFR) AF: 0.00 AC: 0 AN: 41450

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68026

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial infantile myoclonic epilepsy Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	4.8
DANN	Benign	0.34
PhyloP100		0.67
PromoterAI		0.021	Neutral

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.024
dbscSNV1_RF	Benign	0.28
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1280271387; hg19: chr16-2546035;