rs142808899

Positions:

• chr11-71437868-C-A
• chr11-71437868-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_001360.3(DHCR7):​c.907G>T​(p.Gly303Trp) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,740 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G303R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: DHCR7 NM_001360.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 6.89

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-71437868-C-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 11-71437868-C-A is Pathogenic according to our data. Variant chr11-71437868-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 640944.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DHCR7	NM_001360.3	c.907G>T	p.Gly303Trp	missense_variant	8/9	ENST00000355527.8	NP_001351.2
DHCR7	NM_001163817.2	c.907G>T	p.Gly303Trp	missense_variant	8/9		NP_001157289.1
DHCR7	XM_011544777.3	c.907G>T	p.Gly303Trp	missense_variant	8/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8	c.907G>T	p.Gly303Trp	missense_variant	8/9	1	NM_001360.3	ENSP00000347717.4
DHCR7	ENST00000685320.1	c.322G>T	p.Gly108Trp	missense_variant	7/8			ENSP00000509319.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251326 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135854

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461740 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 727164

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Smith-Lemli-Opitz syndrome Pathogenic:1 Uncertain:1

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Jan 24, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 23, 2023	This sequence change replaces glycine, which is neutral and non-polar, with tryptophan, which is neutral and slightly polar, at codon 303 of the DHCR7 protein (p.Gly303Trp). This variant is present in population databases (rs142808899, gnomAD 0.003%). This missense change has been observed in individual(s) with clinical features of DHCR7-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 640944). 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 disrupts the p.Gly303 amino acid residue in DHCR7. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16044199, 20052364, 28503313). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D;D;D
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.98	.;D;D;D
M_CAP	Pathogenic	0.29	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Uncertain	0.47	D
MutationAssessor	Pathogenic	4.3	H;H;.;.
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-7.6	D;D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		1.0	D;D;.;.
Vest4		0.99
MutPred		0.95		Loss of catalytic residue at H299 (P = 0.3436);Loss of catalytic residue at H299 (P = 0.3436);.;.;
MVP		0.98
MPC		0.62
ClinPred		1.0	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.96
gMVP		0.99

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

LitVar

Other links and lift over

dbSNP: rs142808899; hg19: chr11-71148914; COSMIC: COSV62794760; COSMIC: COSV62794760;