22-43063902-G-T

Variant names:

• chr22-43063902-G-T
• rs1279755974
• NM_012263.5:c.658C>A

Variant summary

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

The NM_012263.5(TTLL1):​c.658C>A​(p.Arg220Arg) 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 1,461,802 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.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TTLL1 NM_012263.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.51
• Publications: 0 publications found

Genes affected

TTLL1 (HGNC:1312): (TTL family tubulin polyglutamylase complex subunit L1) Predicted to enable tubulin binding activity and tubulin-glutamic acid ligase activity. Predicted to be involved in microtubule cytoskeleton organization and protein polyglutamylation. Predicted to act upstream of or within several processes, including cerebellar Purkinje cell differentiation; mucociliary clearance; and regulation of blastocyst development. Predicted to be located in cytoplasm; extracellular region; and microtubule cytoskeleton. Predicted to be active in cilium. [provided by Alliance of Genome Resources, Apr 2022]

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_012263.5. 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
	TTLL1	NM_012263.5	MANE Select	c.658C>A	p.Arg220Arg	synonymous	Exon 7 of 11	NP_036395.1	O95922-1
	TTLL1	NR_027779.2		n.966C>A		non_coding_transcript_exon	Exon 8 of 12

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTLL1	ENST00000266254.12	TSL:1 MANE Select	c.658C>A	p.Arg220Arg	synonymous	Exon 7 of 11	ENSP00000266254.7	O95922-1
	TTLL1	ENST00000331018.8	TSL:1	c.658C>A	p.Arg220Arg	synonymous	Exon 5 of 8	ENSP00000333734.7	O95922-4
	TTLL1	ENST00000439248.5	TSL:1	n.*582C>A		non_coding_transcript_exon	Exon 8 of 12	ENSP00000401518.1	O95922-2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461802 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727200

⚠️ 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: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44714

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111972

Other (OTH) AF: 0.00 AC: 0 AN: 60392

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0296732), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.29
CADD	Benign	19
DANN	Benign	0.64
PhyloP100		3.5

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.40		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.40		Position offset: -2

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

Other links and lift over

dbSNP: rs1279755974; hg19: chr22-43459908;