rs1057517657

Positions:

• chr11-62705371-G-A
• chr11-62705371-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_001122955.4(BSCL2):​c.334C>T​(p.Leu112Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,830 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BSCL2 NM_001122955.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 5.71

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]

BSCL2 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a topological_domain Lumenal (size 194) in uniprot entity BSCL2_HUMAN there are 12 pathogenic changes around while only 0 benign (100%) in NM_001122955.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.879

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BSCL2	NM_001122955.4	c.334C>T	p.Leu112Phe	missense_variant	2/11	ENST00000360796.10	NP_001116427.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BSCL2	ENST00000360796.10	c.334C>T	p.Leu112Phe	missense_variant	2/11	1	NM_001122955.4	ENSP00000354032.5
HNRNPUL2-BSCL2	ENST00000403734.2	n.*385C>T		non_coding_transcript_exon_variant	15/24	2		ENSP00000456010.1
HNRNPUL2-BSCL2	ENST00000403734.2	n.*385C>T		3_prime_UTR_variant	15/24	2		ENSP00000456010.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251102 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135762

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

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: 1461830 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727208

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

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.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 14, 2023

This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 48 of the BSCL2 protein (p.Leu48Phe). This variant is present in population databases (no rsID available, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with BSCL2-related conditions. ClinVar contains an entry for this variant (Variation ID: 372114). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on BSCL2 protein function. 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. -

Congenital generalized lipodystrophy type 2 Other:1

not provided, no classification provided

literature only

GeneReviews

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.60
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.82	.;.;.;D;D;D;.;D;D;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Pathogenic	0.97	D;D;D;.;.;D;D;D;D;D
M_CAP	Uncertain	0.094	D
MetaRNN	Pathogenic	0.88	D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Uncertain	2.4	.;M;.;M;M;M;.;.;.;.
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.0	D;D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.83
Sift	Uncertain	0.022	D;D;D;D;D;D;D;D;D;D
Sift4G	Uncertain	0.010	D;D;D;D;D;D;.;.;.;D
Polyphen		1.0	.;D;.;D;D;D;.;.;.;.
Vest4		0.65
MutPred		0.71		.;Gain of sheet (P = 0.0827);.;Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);.;Gain of sheet (P = 0.0827);.;
MVP		0.98
ClinPred		0.95	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.25
gMVP		0.59

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: rs1057517657; hg19: chr11-62472843;