8-67164395-GAA-GAAA

Variant names:

• chr8-67164395-G-GA
• rs863225190
• NM_001382391.1:c.2723dupA

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_001382391.1(CSPP1):​c.2723dupA​(p.Asn908LysfsTer15) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000321 in 1,370,156 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000032 (0 hom.)
• Consequence: CSPP1 NM_001382391.1 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.28
• Publications: 4 publications found

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]

CSPP1 Gene-Disease associations (from GenCC):

• Joubert syndrome 21

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
• Joubert syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Joubert syndrome with Jeune asphyxiating thoracic dystrophy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Meckel syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 10 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CSPP1	NM_001382391.1	c.2723dupA	p.Asn908LysfsTer15	frameshift_variant	Exon 24 of 31	ENST00000678616.1	NP_001369320.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CSPP1	ENST00000678616.1	c.2723dupA	p.Asn908LysfsTer15	frameshift_variant	Exon 24 of 31		NM_001382391.1	ENSP00000504733.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000321 AC: 44 AN: 1370156 Hom.: 0 Cov.: 22 AF XY: 0.0000320 AC XY: 22 AN XY: 686738

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

African (AFR) AF: 0.0000316 AC: 1 AN: 31664

American (AMR) AF: 0.00 AC: 0 AN: 44018

Ashkenazi Jewish (ASJ) AF: 0.0000394 AC: 1 AN: 25410

East Asian (EAS) AF: 0.00 AC: 0 AN: 39248

South Asian (SAS) AF: 0.0000120 AC: 1 AN: 83492

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53036

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5580

European-Non Finnish (NFE) AF: 0.0000369 AC: 38 AN: 1030638

Other (OTH) AF: 0.0000526 AC: 3 AN: 57070

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		6.3
Mutation Taster		=10/190	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs863225190; hg19: chr8-68076630; COSMIC: COSV51586423;