8-64596876-GA-GAA

Variant names:

• chr8-64596876-G-GA
• rs1060502224
• NM_004820.5:c.1286dupT

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_004820.5(CYP7B1):​c.1286dupT​(p.Lys430GlnfsTer42) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000103 in 1,461,142 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: CYP7B1 NM_004820.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 0.238

Genes affected

CYP7B1 (HGNC:2652): (cytochrome P450 family 7 subfamily B member 1) This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This endoplasmic reticulum membrane protein catalyzes the first reaction in the cholesterol catabolic pathway of extrahepatic tissues, which converts cholesterol to bile acids. This enzyme likely plays a minor role in total bile acid synthesis, but may also be involved in the development of atherosclerosis, neurosteroid metabolism and sex hormone synthesis. Mutations in this gene have been associated with hereditary spastic paraplegia (SPG5 or HSP), an autosomal recessive disorder. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.155 CDS is truncated, and there are 3 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 8-64596876-G-GA is Pathogenic according to our data. Variant chr8-64596876-G-GA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 409026.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP7B1	NM_004820.5	c.1286dupT	p.Lys430GlnfsTer42	frameshift_variant	Exon 6 of 6	ENST00000310193.4	NP_004811.1
CYP7B1	XM_017014002.2	c.1352dupT	p.Lys452GlnfsTer42	frameshift_variant	Exon 7 of 7		XP_016869491.1
CYP7B1	NM_001324112.2	c.1234-7033dupT		intron_variant	Intron 5 of 6		NP_001311041.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP7B1	ENST00000310193.4	c.1286dupT	p.Lys430GlnfsTer42	frameshift_variant	Exon 6 of 6	1	NM_004820.5	ENSP00000310721.3
CYP7B1	ENST00000523954.1	n.508-7033dupT		intron_variant	Intron 3 of 4	3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000798 AC: 2 AN: 250734 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135520

Gnomad AFR exome AF: 0.00

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461142 Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7 AN XY: 726818

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: 0.0000126

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Spastic paraplegia Pathogenic:1

Feb 02, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys430Glnfs*42) in the CYP7B1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 77 amino acid(s) of the CYP7B1 protein. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with CYP7B1-related conditions. ClinVar contains an entry for this variant (Variation ID: 409026). This variant disrupts a region of the CYP7B1 protein in which other variant(s) (p.Arg486Cys) have been determined to be pathogenic (PMID: 19439320, 21541746, 21623769, 24117163). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Hereditary spastic paraplegia 5A;C3151147:Congenital bile acid synthesis defect 3 Pathogenic:1

Jan 14, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1060502224; hg19: chr8-65509433;