NM_003774.5:c.978G>C

Variant names:

• chr12-89523572-C-G
• rs200228838
• NM_003774.5:c.978G>C

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_003774.5(GALNT4):​c.978G>C​(p.Thr326Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. T326T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GALNT4 NM_003774.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -2.66
• Publications: 2 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: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.89).
• BP7: Synonymous conserved (PhyloP=-2.66 with no splicing effect.

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.978G>C	p.Thr326Thr	synonymous	Exon 1 of 1	NP_003765.2
	POC1B	NM_172240.3	MANE Select	c.100+1548G>C		intron	N/A	NP_758440.1	Q8TC44-1
	POC1B-GALNT4	NM_001199781.2		c.969G>C	p.Thr323Thr	synonymous	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.978G>C	p.Thr326Thr	synonymous	Exon 1 of 1	ENSP00000436604.2	Q8N4A0-1
	POC1B-GALNT4	ENST00000548729.5	TSL:2	c.969G>C	p.Thr323Thr	synonymous	Exon 3 of 3	ENSP00000447852.1	F8VUJ3
	POC1B	ENST00000313546.8	TSL:1 MANE Select	c.100+1548G>C		intron	N/A	ENSP00000323302.3	Q8TC44-1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 87

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 1

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.075
DANN	Benign	0.53
PhyloP100		-2.7

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: rs200228838; hg19: chr12-89917349;