rs886044494

Positions:

• chr11-71438968-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_001360.3(DHCR7):​c.742T>C​(p.Trp248Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,710 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W248C) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: DHCR7 NM_001360.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.01

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-71438966-C-A is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DHCR7	NM_001360.3	c.742T>C	p.Trp248Arg	missense_variant	7/9	ENST00000355527.8	NP_001351.2
DHCR7	NM_001163817.2	c.742T>C	p.Trp248Arg	missense_variant	7/9		NP_001157289.1
DHCR7	XM_011544777.3	c.742T>C	p.Trp248Arg	missense_variant	7/9		XP_011543079.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8	c.742T>C	p.Trp248Arg	missense_variant	7/9	1	NM_001360.3	ENSP00000347717	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251306 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135902

Gnomad AFR exome AF: 0.0000616

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 AF: 0.00000205 AC: 3 AN: 1461710 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727154

Gnomad4 AFR exome AF: 0.0000299

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Dec 23, 2021

Variant summary: DHCR7 c.742T>C (p.Trp248Arg) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251306 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.742T>C has been reported in the literature in individuals affected with Smith-Lemli-Opitz Syndrome (Waye_2002, Wassif_2005). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Smith-Lemli-Opitz syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Dec 28, 2017

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Aug 24, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D;D;.
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	.;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.2	H;H;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-13	D;D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;.
Polyphen		1.0	D;D;.;.
Vest4		0.99
MutPred		0.89		Gain of methylation at W248 (P = 0.0101);Gain of methylation at W248 (P = 0.0101);.;.;
MVP		0.98
MPC		0.76
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.96
gMVP		1.0

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: rs886044494; hg19: chr11-71150014;