rs886041354

Positions:

• chr11-71438970-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2 PP3_Moderate PP5_Very_Strong

The NM_001360.3(DHCR7):​c.740C>T​(p.Ala247Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,716 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: DHCR7 NM_001360.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.59

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 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.874
• PP5: Variant 11-71438970-G-A is Pathogenic according to our data. Variant chr11-71438970-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 280065.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-71438970-G-A is described in Lovd as [Likely_pathogenic]. Variant chr11-71438970-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DHCR7	NM_001360.3	c.740C>T	p.Ala247Val	missense_variant	7/9	ENST00000355527.8	NP_001351.2
DHCR7	NM_001163817.2	c.740C>T	p.Ala247Val	missense_variant	7/9		NP_001157289.1
DHCR7	XM_011544777.3	c.740C>T	p.Ala247Val	missense_variant	7/9		XP_011543079.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8	c.740C>T	p.Ala247Val	missense_variant	7/9	1	NM_001360.3	ENSP00000347717	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461716 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727156

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Alfa AF: 0.0000740 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Smith-Lemli-Opitz syndrome Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Sep 02, 2022	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Smith-Lemli-Opitz syndrome (MIM#270400). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0115 - Variants in this gene are known to have variable expressivity. Exceptionally mild and severe cases have been reported, with intra and interfamilial variable expressivity (PMID: 35305950). (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to valine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (1 heterozygote, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated ergosterol biosynthesis ERG4/ERG24 family domain (DECIPHER). (I) 0703 - Other missense variants comparable to the one identified in this case have moderate previous evidence for pathogenicity. p.(Ala247Ser) and p.(Ala247Thr) have been classified as likely pathogenic and pathogenic respectively by a clinical laboratory in ClinVar. (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as pathogenic and likely pathogenic by clinical laboratories in ClinVar, and has also been observed as compound heterozygous in several individuals with Smith-Lemli-Opitz syndrome in the literature (PMIDs: 10995508, 10677299, 23293579, 9653161). (SP) 1005 - Clinically accredited laboratory assay specific to gene product shows abnormal protein function. Markedly increased 7-dehydrocholesterol levels have been observed in a blood sample of this individual. (SP) 1205 - This variant has been shown to be maternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Nov 07, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 24, 2023	This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 247 of the DHCR7 protein (p.Ala247Val). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Smith–Lemli–Opitz syndrome (PMID: 9653161, 10995508, 15896653). 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: 280065). 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. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Oct 03, 2023

Not observed at 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: 10995508, 9653161, 15464432, 11111101, 23293579, 15670717, 11175299, 10677299, 24500076, 23042628, 12914579) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.82
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.96	D;D;D;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	.;D;D;D
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.87	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	M;M;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-3.4	D;D;D;D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0040	D;D;D;D
Sift4G	Uncertain	0.0060	D;D;D;.
Polyphen		1.0	D;D;.;.
Vest4		0.98
MutPred		0.56		Loss of catalytic residue at A247 (P = 0.0944);Loss of catalytic residue at A247 (P = 0.0944);.;.;
MVP		0.95
MPC		0.47
ClinPred		0.97	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.58
gMVP		0.96

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: rs886041354; hg19: chr11-71150016;