chr20-34295517-T-C

Variant names:

Variant summary

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

The NM_000687.4(AHCY):c.97A>G(p.Met33Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,952 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 (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

AHCY
NM_000687.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.89

Publications

0 publications found

Variant links:

Genes affected

AHCY (HGNC:343): (adenosylhomocysteinase) S-adenosylhomocysteine hydrolase belongs to the adenosylhomocysteinase family. It catalyzes the reversible hydrolysis of S-adenosylhomocysteine (AdoHcy) to adenosine (Ado) and L-homocysteine (Hcy). Thus, it regulates the intracellular S-adenosylhomocysteine (SAH) concentration thought to be important for transmethylation reactions. Deficiency in this protein is one of the different causes of hypermethioninemia. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jun 2009]

AHCY Gene-Disease associations (from GenCC):

hypermethioninemia with deficiency of S-adenosylhomocysteine hydrolase
Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen

AHCY 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, 0.906

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AHCY	NM_000687.4 link	c.97A>G	p.Met33Val	missense_variant	Exon 2 of 10	ENST00000217426.7	NP_000678.1	P23526-1A0A384MTQ3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AHCY	ENST00000217426.7 link	c.97A>G	p.Met33Val	missense_variant	Exon 2 of 10	1	NM_000687.4	ENSP00000217426.2		P23526-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152208

Hom.:

Cov.:

show subpopulations

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:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461744

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727182

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53324

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111994

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152208

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74360

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41450

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.000207

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Hypermethioninemia with deficiency of S-adenosylhomocysteine hydrolase

Uncertain:1

Jan 13, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In summary, this variant is a novel missense change with uncertain impact on protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a AHCY-related disease. This sequence change replaces methionine with valine at codon 33 of the AHCY protein (p.Met33Val). The methionine residue is highly conserved and there is a small physicochemical difference between methionine and valine. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.36

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.83

D;.

Eigen

Benign

0.13

Eigen_PC

Benign

0.21

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.97

D;D

M_CAP

Uncertain

0.12

MetaRNN

Pathogenic

0.91

D;D

MetaSVM

Uncertain

-0.028

MutationAssessor

Pathogenic

3.3

M;.

PhyloP100

7.9

PrimateAI

Uncertain

0.61

PROVEAN

Uncertain

-3.3

D;D

REVEL

Pathogenic

0.79

Sift

Uncertain

0.011

D;D

Sift4G

Uncertain

0.019

D;D

Polyphen

0.037

B;.

Vest4

0.84

MutPred

0.73

Gain of helix (P = 0.0425);.;

MVP

0.93

MPC

0.64

ClinPred

0.98

GERP RS

5.0

Varity_R

0.62

gMVP

0.90

Mutation Taster

=21/79

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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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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