chr22-18130836-C-A

Variant names:

• chr22-18130836-C-A
• rs2234338
• NM_018943.3:c.1057-7C>A

Variant summary

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

The NM_018943.3(TUBA8):​c.1057-7C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,248 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TUBA8 NM_018943.3 splice_region, intron
• Scores: Splicing: ADA: 0.0005281
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.422
• Publications: 6 publications found

Genes affected

TUBA8 (HGNC:12410): (tubulin alpha 8) This gene encodes a member of the alpha tubulin protein family. Alpha tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. Mutations in this gene are associated with polymicrogyria and optic nerve hypoplasia. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jul 2010]

TUBA8 Gene-Disease associations (from GenCC):

• polymicrogyria with optic nerve hypoplasia

  Inheritance: Unknown, AR Classification: SUPPORTIVE, LIMITED, NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet, ClinGen

ENSG00000288683 (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=-0.75).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_018943.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBA8	NM_018943.3	MANE Select	c.1057-7C>A		splice_region intron	N/A	NP_061816.1
	TUBA8	NM_001193414.2		c.859-7C>A		splice_region intron	N/A	NP_001180343.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBA8	ENST00000330423.8	TSL:1 MANE Select	c.1057-7C>A		splice_region intron	N/A	ENSP00000333326.3
	TUBA8	ENST00000416740.2	TSL:1	c.859-7C>A		splice_region intron	N/A	ENSP00000412646.2
	ENSG00000288683	ENST00000474897.6	TSL:5	n.*947-7C>A		splice_region intron	N/A	ENSP00000434235.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461248 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726946

African (AFR) AF: 0.00 AC: 0 AN: 33460

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86236

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53384

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5332

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111950

Other (OTH) AF: 0.0000166 AC: 1 AN: 60340

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.75
CADD	Benign	13
DANN	Benign	0.69
PhyloP100		0.42

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00053
dbscSNV1_RF	Benign	0.074
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

Other links and lift over

dbSNP: rs2234338; hg19: chr22-18613603;