rs1553122926

Positions:

• chr1-26457880-G-A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 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 (★★).

• 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

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 16 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, 4 uncertain in NM_205861.3
• PM2: Very rare variant in population databases, with high coverage
• 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 id is 488193.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-26457880-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DHDDS	NM_205861.3	c.632G>A	p.Arg211Gln	missense_variant	7/9	ENST00000236342.12	NP_995583.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DHDDS	ENST00000236342.12	c.632G>A	p.Arg211Gln	missense_variant	7/9	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

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 06, 2024	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. -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics Munich, Klinikum Rechts Der Isar, TU München	Jan 16, 2020	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 24, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	Jul 29, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, University of Leipzig Medical Center	Jul 12, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Oct 02, 2021	Same nucleotide change resulting in same amino acid change has been previously reported as de novoo and observed in at least four similarly affected unrelated individuals (3billion dataset, PMID: 29100083, PS2 and PS4). It is not observed in the gnomAD v2.1.1 dataset (PM2). The variant was observed as assumed (i.e. paternity and maternity not confirmed) de novoo (3billion dataset, PM6). Missense changes are a common disease-causing mechanism (PP2). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.889, 3Cnet: 0.501, PP3). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 14, 2022	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) -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Dec 24, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2020	- -

Retinitis pigmentosa 59 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 14, 2023

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. 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;.;.
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

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: rs1553122926; hg19: chr1-26784371;