X-85864699-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_000390.4(CHM):c.1893A>G(p.Ile631Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000414 in 1,207,853 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000090 ( 0 hom., 0 hem., cov: 23)

Exomes 𝑓: 0.0000036 ( 0 hom. 1 hem. )

Consequence

CHM
NM_000390.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -0.319

Variant links:

Genes affected

CHM (HGNC:1940): (CHM Rab escort protein) This gene encodes component A of the RAB geranylgeranyl transferase holoenzyme. In the dimeric holoenzyme, this subunit binds unprenylated Rab GTPases and then presents them to the catalytic Rab GGTase subunit for the geranylgeranyl transfer reaction. Rab GTPases need to be geranylgeranyled on either one or two cysteine residues in their C-terminus to localize to the correct intracellular membrane. Mutations in this gene are a cause of choroideremia; also known as tapetochoroidal dystrophy (TCD). This X-linked disease is characterized by progressive dystrophy of the choroid, retinal pigment epithelium and retina. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Mar 2016]

CHM links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.09212878).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHM	NM_000390.4 link	c.1893A>G	p.Ile631Met	missense_variant	Exon 15 of 15	ENST00000357749.7	NP_000381.1	P24386-1A8K545

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHM	ENST00000357749.7 link	c.1893A>G	p.Ile631Met	missense_variant	Exon 15 of 15	1	NM_000390.4	ENSP00000350386.2		P24386-1
CHM	ENST00000467744.2 link	n.127-1605A>G		intron_variant	Intron 2 of 2	5

Frequencies

GnomAD3 genomes

AF:

0.00000896

AC:

AN:

111599

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

33771

show subpopulations

Gnomad AFR

AF:

0.0000326

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000559

AC:

AN:

178909

Hom.:

AF XY:

0.00

AC XY:

AN XY:

63897

show subpopulations

Gnomad AFR exome

AF:

0.0000773

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

0.00000365

AC:

AN:

1096254

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

361794

show subpopulations

Gnomad4 AFR exome

AF:

0.000152

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000896

AC:

AN:

111599

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

33771

show subpopulations

Gnomad4 AFR

AF:

0.0000326

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000264

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Choroideremia

Uncertain:1

Jan 21, 2021

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Inborn genetic diseases

Uncertain:1

Aug 05, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1893A>G (p.I631M) alteration is located in exon 15 (coding exon 15) of the CHM gene. This alteration results from a A to G substitution at nucleotide position 1893, causing the isoleucine (I) at amino acid position 631 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Aug 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine with methionine at codon 631 of the CHM protein (p.Ile631Met). The isoleucine residue is weakly conserved and there is a small physicochemical difference between isoleucine and methionine. This variant is present in population databases (rs778210722, ExAC 0.01%). This variant has not been reported in the literature in individuals affected with CHM-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The methionine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.071

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.56

CADD

Benign

0.57

DANN

Benign

0.58

DEOGEN2

Benign

0.16

FATHMM_MKL

Benign

0.058

LIST_S2

Benign

0.52

M_CAP

Benign

0.045

MetaRNN

Benign

0.092

MetaSVM

Benign

-0.58

MutationAssessor

Benign

1.4

PrimateAI

Benign

0.29

PROVEAN

Benign

-0.19

REVEL

Benign

0.14

Sift

Benign

0.14

Sift4G

Benign

0.10

Polyphen

0.021

Vest4

0.065

MVP

0.65

MPC

0.20

ClinPred

0.013

GERP RS

-0.80

Varity_R

0.087

gMVP

0.12

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over