rs121909766

Variant names:

• chr11-71437936-T-C
• rs121909766
• NM_001360.3:c.839A>G
• DHCR7 p.Tyr280Cys

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_001360.3(DHCR7):​c.839A>G​(p.Tyr280Cys) 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. Y280D) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: DHCR7 NM_001360.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 6.99
• Publications: 3 publications found

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, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, ClinGen, Myriad Women's Health

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 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 chr11-71437937-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2854167.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 11-71437936-T-C is Pathogenic according to our data. Variant chr11-71437936-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 6790.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001360.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	DHCR7	NM_001360.3	MANE Select	c.839A>G	p.Tyr280Cys	missense	Exon 8 of 9	NP_001351.2	A0A024R5F7
	DHCR7	NM_001425107.1		c.890A>G	p.Tyr297Cys	missense	Exon 9 of 10	NP_001412036.1	A0A804HI25
	DHCR7	NM_001425108.1		c.875A>G	p.Tyr292Cys	missense	Exon 8 of 9	NP_001412037.1	A0A804HJQ7

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	DHCR7	ENST00000355527.8	TSL:1 MANE Select	c.839A>G	p.Tyr280Cys	missense	Exon 8 of 9	ENSP00000347717.4	Q9UBM7
	DHCR7	ENST00000407721.6	TSL:1	c.839A>G	p.Tyr280Cys	missense	Exon 8 of 9	ENSP00000384739.2	Q9UBM7
	DHCR7	ENST00000685320.1		c.254A>G	p.Tyr85Cys	missense	Exon 7 of 8	ENSP00000509319.1	B4E1K5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 34

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Smith-Lemli-Opitz syndrome (2)
1	-	-	DHCR7-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.76
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.3	H
PhyloP100		7.0
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-8.5	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.96
gMVP		0.99
Mutation Taster		=5/95	disease causing (ClinVar)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs121909766;

hg19: chr11-71148982;