chr12-89425181-G-A

Position:

• chr12-89425181-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_172240.3(POC1B):​c.1312C>T​(p.Gln438*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000657 in 152,200 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: POC1B NM_172240.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.63

Genes affected

POC1B (HGNC:30836): (POC1 centriolar protein B) POC1 proteins contain an N-terminal WD40 domain and a C-terminal coiled coil domain and are part of centrosomes. They play an important role in basal body and cilia formation. This gene encodes one of the two POC1 proteins found in humans. Mutation in this gene result in autosomal-recessive cone-rod dystrophy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2014]

POC1B (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 5 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-89425181-G-A is Pathogenic according to our data. Variant chr12-89425181-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 1408249.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POC1B	NM_172240.3	c.1312C>T	p.Gln438*	stop_gained	11/12	ENST00000313546.8	NP_758440.1
POC1B	NM_001199777.2	c.1186C>T	p.Gln396*	stop_gained	10/11		NP_001186706.1
POC1B	NR_037659.2	n.1315C>T		non_coding_transcript_exon_variant	11/12
POC1B	NR_037660.2	n.1351C>T		non_coding_transcript_exon_variant	9/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POC1B	ENST00000313546.8	c.1312C>T	p.Gln438*	stop_gained	11/12	1	NM_172240.3	ENSP00000323302.3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74362

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000192

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 06, 2022

This sequence change creates a premature translational stop signal (p.Gln438*) in the POC1B gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 41 amino acid(s) of the POC1B protein. This variant is not present in population databases (gnomAD no frequency). For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the POC1B protein in which other variant(s) (p.R452*) have been determined to be pathogenic (PMID: 29377742, 33691693). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 1408249). This variant has not been reported in the literature in individuals affected with POC1B-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	41
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Uncertain	0.82	D
Vest4		0.38
GERP RS		5.8

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.33		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.33		Position offset: -20

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

Publications

LitVar

Other links and lift over

dbSNP: rs570958164; hg19: chr12-89818958;