12-89523218-C-T

Variant names:

• chr12-89523218-C-T
• rs369106319
• NM_003774.5:c.1332G>A

Variant summary

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

The NM_003774.5(GALNT4):​c.1332G>A​(p.Trp444*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000657 in 152,214 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: GALNT4 NM_003774.5 stop_gained
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.03
• Publications: 1 publications found

Genes affected

GALNT4 (HGNC:4126): (polypeptide N-acetylgalactosaminyltransferase 4) This gene encodes a member of the UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. GalNAc-Ts initiate mucin-type O-linked glycosylation in the Golgi apparatus by catalyzing the transfer of GalNAc to serine and threonine residues on target proteins. They are characterized by an N-terminal transmembrane domain, a stem region, a lumenal catalytic domain containing a GT1 motif and Gal/GalNAc transferase motif, and a C-terminal ricin/lectin-like domain. GalNAc-Ts have different, but overlapping, substrate specificities and patterns of expression. In vitro, the encoded protein can complement other GalNAc-Ts in the complete O-glycosylation of the mucin-1 tandem repeat and can O-glycosylate the P-selectin glycoprotein ligand-1 molecule. The coding region of this gene is contained within a single exon. Fusion transcripts, which combine part of this gene with the 5' exons of the neighboring POC1B (POC1 centriolar protein homolog B) gene, also exist. [provided by RefSeq, Dec 2010]

POC1B-GALNT4 (HGNC:42957): (POC1B-GALNT4 readthrough) This locus represents naturally occurring transcripts that splice the 5' exons of the POC1B (POC1 centriolar protein homolog B) gene on chromosome 12 to the GALNT4 (UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 4) gene, which is located within a POC1B intron. Alternative splicing results in two transcript variants, one of which encodes a fusion isoform that shares sequence identity with the products of each individual gene. [provided by RefSeq, Dec 2010]

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 Gene-Disease associations (from GenCC):

• cone-rod dystrophy 20

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

  Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics
• cone-rod dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

POC1B-DUSP6 (HGNC:):

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_003774.5. 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
	GALNT4	NM_003774.5	MANE Select	c.1332G>A	p.Trp444*	stop_gained	Exon 1 of 1	NP_003765.2
	POC1B	NM_172240.3	MANE Select	c.100+1902G>A		intron	N/A	NP_758440.1	Q8TC44-1
	POC1B-GALNT4	NM_001199781.2		c.1323G>A	p.Trp441*	stop_gained	Exon 3 of 3	NP_001186710.1	F8VUJ3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GALNT4	ENST00000529983.3	TSL:6 MANE Select	c.1332G>A	p.Trp444*	stop_gained	Exon 1 of 1	ENSP00000436604.2	Q8N4A0-1
	POC1B-GALNT4	ENST00000548729.5	TSL:2	c.1323G>A	p.Trp441*	stop_gained	Exon 3 of 3	ENSP00000447852.1	F8VUJ3
	POC1B	ENST00000313546.8	TSL:1 MANE Select	c.100+1902G>A		intron	N/A	ENSP00000323302.3	Q8TC44-1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152214 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 36

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152214 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74366

African (AFR) AF: 0.00 AC: 0 AN: 41448

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5202

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2094

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	42
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		6.0
Vest4		0.42
GERP RS		5.7
Mutation Taster		=41/159	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs369106319; hg19: chr12-89916995;