11-71435475-C-G

Variant names:

• chr11-71435475-C-G
• rs781687341
• NM_001360.3:c.1328G>C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_001360.3(DHCR7):​c.1328G>C​(p.Arg443Pro) variant causes a missense change. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R443C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: DHCR7 NM_001360.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 6.84

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 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 chr11-71435476-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 557359.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 11-71435475-C-G is Pathogenic according to our data. Variant chr11-71435475-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1071907.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
DHCR7	NM_001360.3	c.1328G>C	p.Arg443Pro	missense_variant	Exon 9 of 9	ENST00000355527.8	NP_001351.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8	c.1328G>C	p.Arg443Pro	missense_variant	Exon 9 of 9	1	NM_001360.3	ENSP00000347717.4
DHCR7	ENST00000685320.1	c.743G>C	p.Arg248Pro	missense_variant	Exon 8 of 8			ENSP00000509319.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248902 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135162

Gnomad AFR exome AF: 0.0000625

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

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 Cov.: 30

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Smith-Lemli-Opitz syndrome Pathogenic:2

May 28, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg443 amino acid residue in DHCR7. Other variant(s) that disrupt this residue have been observed in individuals with DHCR7-related conditions (PMID: 27513191), which suggests that this may be a clinically significant amino acid residue. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has been observed in individual(s) with Smith-Lemli-Opitz syndrome (Invitae). In at least one individual the data is consistent with the variant being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs781687341, ExAC 0.01%). This sequence change replaces arginine with proline at codon 443 of the DHCR7 protein (p.Arg443Pro). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and proline. -

Mar 08, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D;D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	.;D;D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.3	H;H;.
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-6.5	D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D
Sift4G	Uncertain	0.0060	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.98
MutPred		0.97		Gain of catalytic residue at R443 (P = 0.0537);Gain of catalytic residue at R443 (P = 0.0537);.;
MVP		0.99
MPC		0.69
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.98
gMVP		0.99

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: rs781687341; hg19: chr11-71146521;