12-22055484-A-C

Position:

• chr12-22055484-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_018686.6(CMAS):​c.433A>C​(p.Thr145Pro) variant causes a missense change involving the alteration of a 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 (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CMAS NM_018686.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.09

Genes affected

CMAS (HGNC:18290): (cytidine monophosphate N-acetylneuraminic acid synthetase) This gene encodes an enzyme that converts N-acetylneuraminic acid (NeuNAc) to cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-NeuNAc). This process is important in the formation of sialylated glycoprotein and glycolipids. This modification plays a role in cell-cell communications and immune responses. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.887

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CMAS	NM_018686.6	c.433A>C	p.Thr145Pro	missense_variant	3/8	ENST00000229329.7	NP_061156.1
CMAS	NR_135117.2	n.519A>C		non_coding_transcript_exon_variant	3/7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CMAS	ENST00000229329.7	c.433A>C	p.Thr145Pro	missense_variant	3/8	1	NM_018686.6	ENSP00000229329.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 11, 2024

The c.433A>C (p.T145P) alteration is located in exon 3 (coding exon 3) of the CMAS gene. This alteration results from a A to C substitution at nucleotide position 433, causing the threonine (T) at amino acid position 145 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.62	D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D
M_CAP	Uncertain	0.087	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Uncertain	0.53	D
MutationAssessor	Pathogenic	4.6	H
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-5.8	D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.72
MutPred		0.63		Loss of stability (P = 0.2584);
MVP		0.74
MPC		2.2
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.95
gMVP		0.96

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

Publications

LitVar

Other links and lift over

dbSNP: rs1950262120; hg19: chr12-22208418;