rs775773057

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_001360.3(DHCR7):c.682C>T(p.Arg228Trp) variant causes a missense change. The variant allele was found at a frequency of 0.0000211 in 1,614,016 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R228Q) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

DHCR7
NM_001360.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:3

Conservation

PhyloP100: 5.52

Publications

2 publications found

Variant links:

Genes affected

DHCR7 (HGNC:2860): (7-dehydrocholesterol reductase) This gene encodes an enzyme that removes the C(7-8) double bond in the B ring of sterols and catalyzes the conversion of 7-dehydrocholesterol to cholesterol. This gene is ubiquitously expressed and its transmembrane protein localizes to the endoplasmic reticulum membrane and nuclear outer membrane. Mutations in this gene cause Smith-Lemli-Opitz syndrome (SLOS); a syndrome that is metabolically characterized by reduced serum cholesterol levels and elevated serum 7-dehydrocholesterol levels and phenotypically characterized by cognitive disability, facial dysmorphism, syndactyly of second and third toes, and holoprosencephaly in severe cases to minimal physical abnormalities and near-normal intelligence in mild cases. Alternative splicing results in multiple transcript variants that encode the same protein.[provided by RefSeq, Aug 2009]

DHCR7 Gene-Disease associations (from GenCC):

Smith-Lemli-Opitz syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Myriad Women’s Health, Laboratory for Molecular Medicine, ClinGen, Labcorp Genetics (formerly Invitae)

DHCR7 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 13 uncertain in NM_001360.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr11-71439027-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2137193.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.989

PP5

Variant 11-71439028-G-A is Pathogenic according to our data. Variant chr11-71439028-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 558494.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DHCR7	NM_001360.3 link	c.682C>T	p.Arg228Trp	missense_variant	Exon 7 of 9	ENST00000355527.8	NP_001351.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8 link	c.682C>T	p.Arg228Trp	missense_variant	Exon 7 of 9	1	NM_001360.3	ENSP00000347717.4
DHCR7	ENST00000685320.1 link	c.97C>T	p.Arg33Trp	missense_variant	Exon 6 of 8			ENSP00000509319.1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152246

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251396

AF XY:

0.0000294

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000212

AC:

AN:

1461770

Hom.:

Cov.:

AF XY:

0.0000248

AC XY:

AN XY:

727176

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53310

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000243

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152246

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74380

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41470

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68044

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000203

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Smith-Lemli-Opitz syndrome

Pathogenic:1Uncertain:2

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 08, 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 tryptophan, which is neutral and slightly polar, at codon 228 of the DHCR7 protein (p.Arg228Trp). This variant is present in population databases (rs775773057, gnomAD 0.004%). This missense change has been observed in individual(s) with Smith-Lemli-Opitz syndrome (PMID: 15776424, 22226660). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 558494). 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 DHCR7 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

May 23, 2018

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

not provided

Pathogenic:2

Oct 23, 2020

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 23, 2023

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 15776424, 25040602, 22226660, 23042628, 16207203) -

not specified

Uncertain:1

Jun 02, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: DHCR7 c.682C>T (p.Arg228Trp) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 1.6e-05 in 251396 control chromosomes. c.682C>T has been reported in the literature in individuals affected with Smith-Lemli-Opitz Syndrome (example: Witsch-Baumgartner_2005, Quelin_2012, Lanthaler_2015). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 25040602, 22226660, 15776424). ClinVar contains an entry for this variant (Variation ID: 558494). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.88

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.99

D;D;D;.

Eigen

Uncertain

0.41

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Uncertain

0.96

LIST_S2

Pathogenic

0.98

.;D;D;D

M_CAP

Uncertain

0.16

MetaRNN

Pathogenic

0.99

D;D;D;D

MetaSVM

Uncertain

0.30

MutationAssessor

Pathogenic

4.1

H;H;.;.

PhyloP100

5.5

PrimateAI

Pathogenic

0.84

PROVEAN

Pathogenic

-7.3

D;D;D;D

REVEL

Pathogenic

0.94

Sift

Pathogenic

0.0

D;D;D;D

Sift4G

Pathogenic

0.0010

D;D;D;.

Polyphen

1.0

D;D;.;.

Vest4

0.99

MutPred

0.98

Gain of catalytic residue at R228 (P = 0.0527);Gain of catalytic residue at R228 (P = 0.0527);.;.;

MVP

0.97

MPC

0.55

ClinPred

1.0

GERP RS

3.5

PromoterAI

-0.020

Neutral

(source)

Varity_R

0.91

gMVP

0.99

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over