9-72830499-G-T

Variant names:

• chr9-72830499-G-T
• NM_138691.3:c.2178G>T
• TMC1 p.Ala726Ala

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_138691.3(TMC1):​c.2178G>T​(p.Ala726Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. A726A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TMC1 NM_138691.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.434
• Publications: 0 publications found

Genes affected

TMC1 (HGNC:16513): (transmembrane channel like 1) This gene is considered a member of a gene family predicted to encode transmembrane proteins. The specific function of this gene is unknown; however, it is known to be required for normal function of cochlear hair cells. Mutations in this gene have been associated with progressive postlingual hearing loss and profound prelingual deafness. [provided by RefSeq, Jul 2008]

TMC1 Gene-Disease associations (from GenCC):

• nonsyndromic genetic hearing loss

  Inheritance: AD, SD Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Ambry Genetics
• autosomal recessive nonsyndromic hearing loss 7

  Inheritance: AR, Unknown Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• autosomal dominant nonsyndromic hearing loss 36

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

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

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.42).
• BP7: Synonymous conserved (PhyloP=-0.434 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_138691.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TMC1	NM_138691.3	MANE Select	c.2178G>T	p.Ala726Ala	synonymous	Exon 22 of 24	NP_619636.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TMC1	ENST00000297784.10	TSL:1 MANE Select	c.2178G>T	p.Ala726Ala	synonymous	Exon 22 of 24	ENSP00000297784.6	Q8TDI8
	TMC1	ENST00000340019.4	TSL:5	c.2178G>T	p.Ala726Ala	synonymous	Exon 20 of 22	ENSP00000341433.3	Q8TDI8
	TMC1	ENST00000645208.2		c.2178G>T	p.Ala726Ala	synonymous	Exon 21 of 23	ENSP00000494684.1	Q8TDI8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.42
CADD	Benign	2.6
DANN	Benign	0.58
PhyloP100		-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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr9-75445415;