16-89935442-C-T

Variant names:

• chr16-89935442-C-T
• NM_006086.4:c.991C>T
• TUBB3 p.Leu331Leu

Variant summary

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

The NM_006086.4(TUBB3):​c.991C>T​(p.Leu331Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. L331L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TUBB3 NM_006086.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.03
• Publications: 0 publications found

Genes affected

TUBB3 (HGNC:20772): (tubulin beta 3 class III) This gene encodes a class III member of the beta tubulin protein family. Beta tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. This protein is primarily expressed in neurons and may be involved in neurogenesis and axon guidance and maintenance. Mutations in this gene are the cause of congenital fibrosis of the extraocular muscles type 3. Alternate splicing results in multiple transcript variants. A pseudogene of this gene is found on chromosome 6. [provided by RefSeq, Oct 2010]

TUBB3 Gene-Disease associations (from GenCC):

• TUBB3-related tubulinopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• complex cortical dysplasia with other brain malformations 1

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Illumina, G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• fibrosis of extraocular muscles, congenital, 3A, with or without extraocular involvement

  Inheritance: AD Classification: STRONG Submitted by: G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• congenital fibrosis of extraocular muscles

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• tubulinopathy-associated dysgyria

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000198211 (HGNC:):

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=-0.39).
• BP7: Synonymous conserved (PhyloP=1.03 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006086.4. 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
	TUBB3	NM_006086.4	MANE Select	c.991C>T	p.Leu331Leu	synonymous	Exon 4 of 4	NP_006077.2	Q13509-1
	TUBB3	NM_001197181.2		c.775C>T	p.Leu259Leu	synonymous	Exon 4 of 4	NP_001184110.1	Q13509-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB3	ENST00000315491.12	TSL:1 MANE Select	c.991C>T	p.Leu331Leu	synonymous	Exon 4 of 4	ENSP00000320295.7	Q13509-1
	ENSG00000198211	ENST00000556922.1	TSL:2	c.2032C>T	p.Leu678Leu	synonymous	Exon 5 of 5	ENSP00000451560.1	A0A0B4J269
	TUBB3	ENST00000554444.5	TSL:2	c.775C>T	p.Leu259Leu	synonymous	Exon 4 of 4	ENSP00000451617.1	Q13509-2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461862 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727232

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.39
CADD	Benign	12
DANN	Benign	0.79
PhyloP100		1.0

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: chr16-90001850;