rs758843908

Variant names:

• chr11-62692410-AG-A
• rs758843908
• NM_001122955.4:c.828delC

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001122955.4(BSCL2):​c.828delC​(p.Tyr277ThrfsTer20) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,846 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: BSCL2 NM_001122955.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 U:1
• Conservation: PhyloP100: 0.231

Genes affected

BSCL2 (HGNC:15832): (BSCL2 lipid droplet biogenesis associated, seipin) This gene encodes the multi-pass transmembrane protein protein seipin. This protein localizes to the endoplasmic reticulum and may be important for lipid droplet morphology. Mutations in this gene have been associated with congenital generalized lipodystrophy type 2 or Berardinelli-Seip syndrome, a rare autosomal recessive disease characterized by a near absence of adipose tissue and severe insulin resistance. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. Naturally occurring read-through transcription occurs between this locus and the neighboring locus HNRNPUL2 (heterogeneous nuclear ribonucleoprotein U-like 2).[provided by RefSeq, Mar 2011]

HNRNPUL2-BSCL2 (HGNC:49189): (HNRNPUL2-BSCL2 readthrough (NMD candidate)) This locus represents naturally occurring read-through transcription between the neighboring HNRNPUL2 (heterogeneous nuclear ribonucleoprotein U-like 2) and BSCL2 (Berardinelli-Seip congenital lipodystrophy 2 (seipin)) genes on chromosome 11. The read-through transcript is a candidate for nonsense-mediated mRNA decay (NMD), and is unlikely to produce a protein product. [provided by RefSeq, Mar 2011]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-62692410-AG-A is Pathogenic according to our data. Variant chr11-62692410-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 4540.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-62692410-AG-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BSCL2	NM_001122955.4	c.828delC	p.Tyr277ThrfsTer20	frameshift_variant	Exon 6 of 11	ENST00000360796.10	NP_001116427.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BSCL2	ENST00000360796.10	c.828delC	p.Tyr277ThrfsTer20	frameshift_variant	Exon 6 of 11	1	NM_001122955.4	ENSP00000354032.5
HNRNPUL2-BSCL2	ENST00000403734.2	n.*879delC		non_coding_transcript_exon_variant	Exon 19 of 24	2		ENSP00000456010.1
HNRNPUL2-BSCL2	ENST00000403734.2	n.*879delC		3_prime_UTR_variant	Exon 19 of 24	2		ENSP00000456010.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251342 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135844

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: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461846 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 727218

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: 0.000104

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Mar 23, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Tyr213Thrfs*20) in the BSCL2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BSCL2 are known to be pathogenic (PMID: 11479539, 23564749). This variant is present in population databases (rs758843908, ExAC 0.01%). This variant has been observed in individual(s) with Berardinelli–Seip congenital lipodystrophy (PMID: 11479539, 23659685). This variant is also known as c.980delC (p.F213fsX232) in the literature. ClinVar contains an entry for this variant (Variation ID: 4540). -

Congenital generalized lipodystrophy type 2 Pathogenic:1

Aug 01, 2001

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Berardinelli-Seip congenital lipodystrophy Uncertain:1

Jan 06, 2016

Inherited Neuropathy Consortium Ii, University Of Miami

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

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: rs758843908; hg19: chr11-62459882;