X-85864672-C-T

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 2P and 11B. PM2 BP4_Strong BP6_Moderate BP7 BS2

The NM_000390.4(CHM):c.1920G>A(p.Lys640=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000182 in 1,096,682 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. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 1 hem.)
• Consequence: CHM NM_000390.4 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:2
• Conservation: PhyloP100: 0.00400

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 Benign. Variant got -9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.75).
• BP6: Variant X-85864672-C-T is Benign according to our data. Variant chrX-85864672-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 794377.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=0.004 with no splicing effect.
• BS2: High Hemizygotes in GnomAdExome at 2 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHM	NM_000390.4	c.1920G>A	p.Lys640=	synonymous_variant	15/15	ENST00000357749.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHM	ENST00000357749.7	c.1920G>A	p.Lys640=	synonymous_variant	15/15	1	NM_000390.4	P1
CHM	ENST00000467744.2	n.127-1578G>A		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD3 exomes AF: 0.0000167 AC: 3 AN: 179599 Hom.: 0 AF XY: 0.0000310 AC XY: 2 AN XY: 64573

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000220

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: 0.00000182 AC: 2 AN: 1096682 Hom.: 0 Cov.: 29 AF XY: 0.00000276 AC XY: 1 AN XY: 362356

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000664

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 Cov.: 23

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, single submitter

Submissions by phenotype

Choroideremia Benign:1

Likely benign, no assertion criteria provided

clinical testing

Natera, Inc.

Jan 06, 2021

- -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Aug 28, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.75
Cadd	Benign	1.1
Dann	Benign	0.49

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: rs748006115; hg19: chrX-85119677;