rs1553122926

Variant names:

• chr1-26457880-G-A
• rs1553122926
• NM_205861.3:c.632G>A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_205861.3(DHDDS):​c.632G>A​(p.Arg211Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R211G) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: DHDDS NM_205861.3 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 9.88
• Publications: 3 publications found

Genes affected

DHDDS (HGNC:20603): (dehydrodolichyl diphosphate synthase subunit) The protein encoded by this gene catalyzes cis-prenyl chain elongation to produce the polyprenyl backbone of dolichol, a glycosyl carrier lipid required for the biosynthesis of several classes of glycoproteins. Mutations in this gene are associated with retinitis pigmentosa type 59. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Aug 2011]

DHDDS-AS1 (HGNC:40925): (DHDDS antisense RNA 1)

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_205861.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-26457879-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3839707.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.971
• PP5: Variant 1-26457880-G-A is Pathogenic according to our data. Variant chr1-26457880-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 488193.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DHDDS	NM_205861.3	c.632G>A	p.Arg211Gln	missense_variant	Exon 7 of 9	ENST00000236342.12	NP_995583.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DHDDS	ENST00000236342.12	c.632G>A	p.Arg211Gln	missense_variant	Exon 7 of 9	1	NM_205861.3	ENSP00000236342.7

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental delay and seizures with or without movement abnormalities Pathogenic:6

Jan 16, 2020

Institute of Human Genetics Munich, TUM University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 12, 2018

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 24, 2018

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Dec 15, 2023

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is not observed in the gnomAD v2.1.1 dataset. Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.89 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.73 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000488193 /PMID: 29100083).The variant has been previously reported as de novo in a similarly affected individual (PMID: 29100083, 29100083).The variant has been previously reported as assumed (i.e. paternity and maternity not confirmed) de novo in at least one similarly affected unrelated individual (3billion dataset). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

Jul 29, 2020

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 06, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: DHDDS c.632G>A (p.Arg211Gln) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251468 control chromosomes. c.632G>A has been reported in the literature in individuals affected with Developmental and epileptic encephalopathy and were reported as de novo (examples: Hamdan_2017, Courage_2021, Kim_2022). These data indicate that the variant is very likely associated with the disease. The following publications have been ascertained in the context of this evaluation (PMID: 33798445, 29100083, 35719373). ClinVar contains an entry for this variant (Variation ID: 488193). Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:3

Feb 01, 2020

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 14, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31036916, 29100083, 31440733, 32654954, 32817466, 31661879, 33077723, 33798445, 34504728, 32901917, 27535533) -

Dec 24, 2019

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Retinitis pigmentosa 59 Pathogenic:1

Jun 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 211 of the DHDDS protein (p.Arg211Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant developmental and epileptic encephalopathy (PMID: 29100083, 31440733). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 488193). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt DHDDS protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.84	.;D;.;.;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Pathogenic	4.5	.;H;.;H;.;.
PhyloP100		9.9
PrimateAI	Uncertain	0.71	T
PROVEAN	Uncertain	-4.0	D;D;D;D;D;D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;D;D;D;D;D
Sift4G	Uncertain	0.0050	D;D;D;D;D;D
Polyphen		1.0	.;D;D;D;.;.
Vest4		0.96
MutPred		0.89		.;Gain of phosphorylation at S207 (P = 0.2655);.;Gain of phosphorylation at S207 (P = 0.2655);.;.;
MVP		0.73
MPC		1.5
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.99
gMVP		0.92
Mutation Taster		=0/100	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1553122926; hg19: chr1-26784371;