rs751604696

Variant summary

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

The NM_001360.3(DHCR7):​c.1337G>C​(p.Arg446Pro) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,238 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. R446W) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

DHCR7
NM_001360.3 missense

Scores

14
3
1

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:1

Conservation

PhyloP100: 6.84

Publications

0 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)

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 16 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 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 chr11-71435467-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 551257.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.991
PP5
Variant 11-71435466-C-G is Pathogenic according to our data. Variant chr11-71435466-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1066906.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
DHCR7NM_001360.3 linkc.1337G>C p.Arg446Pro missense_variant Exon 9 of 9 ENST00000355527.8 NP_001351.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
DHCR7ENST00000355527.8 linkc.1337G>C p.Arg446Pro missense_variant Exon 9 of 9 1 NM_001360.3 ENSP00000347717.4
DHCR7ENST00000685320.1 linkc.752G>C p.Arg251Pro missense_variant Exon 8 of 8 ENSP00000509319.1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
AF:
6.85e-7
AC:
1
AN:
1460238
Hom.:
0
Cov.:
30
AF XY:
0.00
AC XY:
0
AN XY:
726500
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33476
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26116
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39696
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51890
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1111938
Other (OTH)
AF:
0.00
AC:
0
AN:
60374
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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
Cov.:
33

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Smith-Lemli-Opitz syndrome Pathogenic:1Uncertain:1
Mar 22, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Sep 13, 2020
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Arg446 amino acid residue in DHCR7. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12818773, 10677299, 27513191, 12270273). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. This variant has not been reported in the literature in individuals with DHCR7-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with proline at codon 446 of the DHCR7 protein (p.Arg446Pro). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and proline.

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
1.0
BayesDel_addAF
Pathogenic
0.58
D
BayesDel_noAF
Pathogenic
0.59
CADD
Pathogenic
31
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.99
D;D;D
Eigen
Pathogenic
0.86
Eigen_PC
Pathogenic
0.78
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Benign
0.0
.;D;D
M_CAP
Pathogenic
0.48
D
MetaRNN
Pathogenic
0.99
D;D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Pathogenic
4.3
H;H;.
PhyloP100
6.8
PrimateAI
Uncertain
0.71
T
PROVEAN
Pathogenic
-6.5
D;D;D
REVEL
Pathogenic
0.96
Sift
Pathogenic
0.0
D;D;D
Sift4G
Uncertain
0.0070
D;D;D
Vest4
0.96
ClinPred
1.0
D
GERP RS
5.1
Varity_R
0.99
gMVP
0.99
Mutation Taster
=25/75
disease causing

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

Other links and lift over

dbSNP: rs751604696; hg19: chr11-71146512; API