11-71442260-T-C

Position:

• chr11-71442260-T-C

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The ENST00000355527.8(DHCR7):​c.412+3A>G variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: DHCR7 ENST00000355527.8 splice_donor_region, intron
• Scores: Splicing: ADA: 0.6740
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.69

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_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.69).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DHCR7	NM_001360.3	c.412+3A>G		splice_donor_region_variant, intron_variant		ENST00000355527.8	NP_001351.2
DHCR7	NM_001163817.2	c.412+3A>G		splice_donor_region_variant, intron_variant			NP_001157289.1
DHCR7	XM_011544777.3	c.412+3A>G		splice_donor_region_variant, intron_variant			XP_011543079.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DHCR7	ENST00000355527.8	c.412+3A>G		splice_donor_region_variant, intron_variant		1	NM_001360.3	ENSP00000347717	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Smith-Lemli-Opitz syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 11, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant disrupts the c.412+3A nucleotide in the DHCR7 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 20635399). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 658384). This variant has been observed in individual(s) with clinical features of Smith-Lemli-Opitz syndrome (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 5 of the DHCR7 gene. It does not directly change the encoded amino acid sequence of the DHCR7 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.69
CADD	Benign	1.0
DANN	Benign	0.61
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.67
dbscSNV1_RF	Benign	0.55
SpliceAI score (max)		0.60		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.60		Position offset: 3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs786200926; hg19: chr11-71153306;