16-89932544-AC-ACCC

Variant names:

• chr16-89932544-A-ACC
• rs112388869
• NM_006086.4:c.58-21_58-20dupCC

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_006086.4(TUBB3):​c.58-21_58-20dupCC variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000207 in 1,446,194 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. There are indicators that this mutation may affect the branch point..

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TUBB3 NM_006086.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.186
• Publications: 2 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, Labcorp Genetics (formerly Invitae), Orphanet
• 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: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

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.58-21_58-20dupCC		intron	N/A	NP_006077.2	Q13509-1
	TUBB3	NM_001197181.2		c.-159-21_-159-20dupCC		intron	N/A	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.58-21_58-20dupCC		intron	N/A	ENSP00000320295.7	Q13509-1
	ENSG00000198211	ENST00000556922.1	TSL:2	c.1099-21_1099-20dupCC		intron	N/A	ENSP00000451560.1	A0A0B4J269
	TUBB3	ENST00000557262.5	TSL:1	n.*41-21_*41-20dupCC		intron	N/A	ENSP00000451985.1	G3V4U2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000400 AC: 1 AN: 249880 AF XY: 0.00000738

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS 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: 0.00000207 AC: 3 AN: 1446194 Hom.: 0 Cov.: 28 AF XY: 0.00000416 AC XY: 3 AN XY: 720428

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33140

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26048

East Asian (EAS) AF: 0.00 AC: 0 AN: 39626

South Asian (SAS) AF: 0.0000349 AC: 3 AN: 85952

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52988

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1098156

Other (OTH) AF: 0.00 AC: 0 AN: 59842

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000416442), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 4

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.19
La Branchor		0.82
BranchPoint Hunter		3.0

Splicing

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

Other links and lift over

dbSNP: rs112388869; hg19: chr16-89998952;