chr8-67190655-T-TA

Position:

• chr8-67190655-T-TA

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001382391.1(CSPP1):​c.3227dup​(p.Tyr1076Ter) variant causes a stop gained, frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,492 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CSPP1 NM_001382391.1 stop_gained, frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 4.36

Genes affected

CSPP1 (HGNC:26193): (centrosome and spindle pole associated protein 1) This gene encodes a centrosome and spindle pole associated protein. The encoded protein plays a role in cell-cycle progression and spindle organization, regulates cytokinesis, interacts with Nephrocystin 8 and is required for cilia formation. Mutations in this gene result in primary cilia abnormalities and classical Joubert syndrome. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Apr 2014]

ARFGEF1 (HGNC:15772): (ADP ribosylation factor guanine nucleotide exchange factor 1) ADP-ribosylation factors (ARFs) play an important role in intracellular vesicular trafficking. The protein encoded by this gene is involved in the activation of ARFs by accelerating replacement of bound GDP with GTP. It contains a Sec7 domain, which may be responsible for guanine-nucleotide exchange activity and also brefeldin A inhibition. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 8-67190655-T-TA is Pathogenic according to our data. Variant chr8-67190655-T-TA is described in ClinVar as [Pathogenic]. Clinvar id is 100669.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CSPP1	NM_001382391.1	c.3227dup	p.Tyr1076Ter	stop_gained, frameshift_variant	29/31	ENST00000678616.1	NP_001369320.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CSPP1	ENST00000678616.1	c.3227dup	p.Tyr1076Ter	stop_gained, frameshift_variant	29/31		NM_001382391.1	ENSP00000504733

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461492 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727104

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Joubert syndrome 21 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 10, 2022	ClinVar contains an entry for this variant (Variation ID: 100669). For these reasons, this variant has been classified as Pathogenic. This premature translational stop signal has been observed in individual(s) with Joubert syndrome and related disorders (PMID: 24360808). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Tyr1071*) in the CSPP1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CSPP1 are known to be pathogenic (PMID: 24360807, 24360808). -
Pathogenic, criteria provided, single submitter	research	UW Hindbrain Malformation Research Program, University of Washington	Feb 23, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	DASA	Nov 03, 2022	The c.3212dup;p.(Tyr1071*) variant creates a premature translational stop signal in the CSPP1 gene. It is expected to result in an absent or disrupted protein product - PVS1. This sequence change has been observed in affected individual(s) and ClinVar contains an entry for this variant (ClinVar ID: 10066; PMID: 24360808) - PS4. This variant is not present in population databases (rs587777141, gnomAD; ABraOM no frequency - http://abraom.ib.usp.br/) - PM2. In summary, the currently available evidence indicates that the variant is pathogenic. -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 02, 2014	- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs587777141; hg19: chr8-68102890;