Genetic Variant CMAS:p.Arg175Cys (chr12-22055574-C-T) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_018686.6(CMAS):c.523C>T(p.Arg175Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,610,152 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R175H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

CMAS
NM_018686.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.17

Publications

1 publications found

Variant links:

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]

CMAS Gene-Disease associations (from GenCC):

intellectual disability
Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

CMAS links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.891

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CMAS	NM_018686.6 link	c.523C>T	p.Arg175Cys	missense_variant	Exon 3 of 8	ENST00000229329.7	NP_061156.1	Q8NFW8-1
CMAS	NR_135117.2 link	n.609C>T		non_coding_transcript_exon_variant	Exon 3 of 7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CMAS	ENST00000229329.7 link	c.523C>T	p.Arg175Cys	missense_variant	Exon 3 of 8	1	NM_018686.6	ENSP00000229329.2		Q8NFW8-1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152168

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000965

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000404

AC:

AN:

247544

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000617

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000823

AC:

AN:

1457866

Hom.:

Cov.:

AF XY:

0.00000828

AC XY:

AN XY:

724868

show subpopulations

African (AFR)

AF:

0.0000900

AC:

AN:

33332

American (AMR)

AF:

0.00

AC:

AN:

43934

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26076

East Asian (EAS)

AF:

0.0000253

AC:

AN:

39592

South Asian (SAS)

AF:

0.0000118

AC:

AN:

84778

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53010

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.00000630

AC:

AN:

1111116

Other (OTH)

AF:

0.00

AC:

AN:

60274

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152286

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74456

show subpopulations

African (AFR)

AF:

0.0000962

AC:

AN:

41562

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.517

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000414

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jun 09, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.523C>T (p.R175C) alteration is located in exon 3 (coding exon 3) of the CMAS gene. This alteration results from a C to T substitution at nucleotide position 523, causing the arginine (R) at amino acid position 175 to be replaced by a cysteine (C). 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

0.68

BayesDel_addAF

Uncertain

0.16

BayesDel_noAF

Pathogenic

0.17

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.28

T;.

Eigen

Uncertain

0.62

Eigen_PC

Uncertain

0.57

FATHMM_MKL

Uncertain

0.91

LIST_S2

Pathogenic

0.99

D;D

M_CAP

Benign

0.010

MetaRNN

Pathogenic

0.89

D;D

MetaSVM

Uncertain

-0.21

MutationAssessor

Uncertain

2.0

M;.

PhyloP100

3.2

PrimateAI

Uncertain

0.77

PROVEAN

Pathogenic

-6.5

D;D

REVEL

Pathogenic

0.74

Sift

Uncertain

0.0010

D;D

Sift4G

Uncertain

0.012

D;D

Polyphen

1.0

D;.

Vest4

0.62

MVP

0.59

MPC

2.2

ClinPred

0.98

GERP RS

4.7

PromoterAI

-0.071

Neutral

(source)

Varity_R

0.59

gMVP

0.86

Mutation Taster

=81/19

polymorphism

(source)

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

Publications

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12-22055574-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over