rs869320633

chr4-16174730-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PVS1_Moderate PM2 PP3_Strong PP5

The NM_153365.3(TAPT1):c.1108-1G>C variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TAPT1 NM_153365.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 7.55

Genes affected

TAPT1 (HGNC:26887): (transmembrane anterior posterior transformation 1) This gene encodes a highly conserved protein that localizes to the centrosome and/or ciliary basal body. Mutations in this gene disrupt Golgi morphology and trafficking and normal primary cilium formation and these mutations are congenitally manifested by severe undermineralization of the intra-uterine skeleton. A mutation in the mouse ortholog of this gene results in homeotic, posterior-to-anterior transformations of the axial skeleton which are similar to the phenotype of mouse homeobox C8 gene mutants. In mouse, this gene is thought to function downstream of homeobox C8 to transduce extracellular patterning information during axial skeleton development. [provided by RefSeq, Jan 2017]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.034624413 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.9, offset of 8, new splice context is: gtttgtttttacgtctacAGtga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 4-16174730-C-G is Pathogenic according to our data. Variant chr4-16174730-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 224906.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TAPT1	NM_153365.3	c.1108-1G>C		splice_acceptor_variant		ENST00000405303.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TAPT1	ENST00000405303.7	c.1108-1G>C		splice_acceptor_variant		1	NM_153365.3	P1
TAPT1	ENST00000507728.1	n.312G>C		non_coding_transcript_exon_variant	1/3	4
TAPT1	ENST00000505603.5	c.*623-1G>C		splice_acceptor_variant, NMD_transcript_variant		2
TAPT1	ENST00000513782.1	c.485-1G>C		splice_acceptor_variant, NMD_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Complex lethal osteochondrodysplasia Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 11, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.40
Cadd	Pathogenic	34
Dann	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.41		Position offset: -9
DS_AL_spliceai		0.96		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs869320633; hg19: chr4-16176353;