NM_003774.5:c.1349G>T

Variant names:

• chr12-89523201-C-A
• NM_003774.5:c.1349G>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_003774.5(GALNT4):​c.1349G>T​(p.Ser450Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S450G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GALNT4 NM_003774.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.07
• Publications: 0 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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.793

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.1349G>T	p.Ser450Ile	missense	Exon 1 of 1	NP_003765.2
	POC1B	NM_172240.3	MANE Select	c.100+1919G>T		intron	N/A	NP_758440.1	Q8TC44-1
	POC1B-GALNT4	NM_001199781.2		c.1340G>T	p.Ser447Ile	missense	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.1349G>T	p.Ser450Ile	missense	Exon 1 of 1	ENSP00000436604.2	Q8N4A0-1
	POC1B-GALNT4	ENST00000548729.5	TSL:2	c.1340G>T	p.Ser447Ile	missense	Exon 3 of 3	ENSP00000447852.1	F8VUJ3
	POC1B	ENST00000313546.8	TSL:1 MANE Select	c.100+1919G>T		intron	N/A	ENSP00000323302.3	Q8TC44-1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 38

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.67
BayesDel_addAF	Uncertain	0.073	D
BayesDel_noAF	Benign	-0.13
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.23	T
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.84	T
M_CAP	Benign	0.040	D
MetaRNN	Pathogenic	0.79	D
MetaSVM	Benign	-0.78	T
MutationAssessor	Uncertain	2.0	M
PhyloP100		3.1
PrimateAI	Uncertain	0.57	T
PROVEAN	Uncertain	-3.4	D
REVEL	Benign	0.25
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.99	D
Vest4		0.67
MutPred		0.62		Loss of disorder (P = 0.0077)
MVP		0.72
MPC		0.63
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.91
gMVP		0.87
Mutation Taster		=57/43	polymorphism

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

hg19: chr12-89916978;