rs886043716

Positions:

• chrX-85963714-GAGTA-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000390.4(CHM):​c.649_652del​(p.Tyr217HisfsTer14) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 23)
• Consequence: CHM NM_000390.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.91

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-85963714-GAGTA-G is Pathogenic according to our data. Variant chrX-85963714-GAGTA-G is described in ClinVar as [Pathogenic]. Clinvar id is 287749.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-85963714-GAGTA-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHM	NM_000390.4	c.649_652del	p.Tyr217HisfsTer14	frameshift_variant	5/15	ENST00000357749.7	NP_000381.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHM	ENST00000357749.7	c.649_652del	p.Tyr217HisfsTer14	frameshift_variant	5/15	1	NM_000390.4	ENSP00000350386	P1
CHM	ENST00000467744.2	n.126+63773_126+63776del		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 23

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 08, 2022	For these reasons, this variant has been classified as Pathogenic. This premature translational stop signal has been observed in individual(s) with choroideremia (PMID: 23811034). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Tyr217Hisfs*14) in the CHM gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CHM are known to be pathogenic (PMID: 9067750, 23811034). -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jun 04, 2016	- -

Computational scores

Source: dbNSFP v4.3

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

Other links and lift over

dbSNP: rs886043716; hg19: chrX-85218719;