chr11-62690411-C-T

Variant names:

• chr11-62690411-C-T
• rs1337416976
• NM_001122955.4:c.1345G>A

Variant summary

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

The NM_001122955.4(BSCL2):​c.1345G>A​(p.Ala449Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,176 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: BSCL2 NM_001122955.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.342

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.0530442).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BSCL2	NM_001122955.4	c.1345G>A	p.Ala449Thr	missense_variant	Exon 11 of 11	ENST00000360796.10	NP_001116427.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BSCL2	ENST00000360796.10	c.1345G>A	p.Ala449Thr	missense_variant	Exon 11 of 11	1	NM_001122955.4	ENSP00000354032.5
HNRNPUL2-BSCL2	ENST00000403734.2	n.*1396G>A		non_coding_transcript_exon_variant	Exon 24 of 24	2		ENSP00000456010.1
HNRNPUL2-BSCL2	ENST00000403734.2	n.*1396G>A		3_prime_UTR_variant	Exon 24 of 24	2		ENSP00000456010.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152176 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251370 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135876

Gnomad AFR exome AF: 0.0000615

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 Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152176 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74340

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Uncertain:1

May 07, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 385 of the BSCL2 protein (p.Ala385Thr). This variant is present in population databases (no rsID available, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with BSCL2-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.066
BayesDel_addAF	Benign	-0.29	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	2.1
DANN	Benign	0.85
DEOGEN2	Benign	0.020	.;.;.;T;T;T;T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.018	N
LIST_S2	Benign	0.82	T;T;T;T;.;.;T
M_CAP	Benign	0.037	D
MetaRNN	Benign	0.053	T;T;T;T;T;T;T
MetaSVM	Benign	-0.79	T
MutationAssessor	Benign	0.0	.;.;.;.;N;N;N
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.1	N;N;N;N;N;N;N
REVEL	Benign	0.13
Sift	Benign	0.40	T;T;T;D;T;T;T
Sift4G	Benign	0.23	T;T;T;.;T;T;T
Polyphen		0.0	.;.;.;.;B;B;B
Vest4		0.033, 0.045, 0.028, 0.030, 0.029
MutPred		0.15		.;.;.;.;Gain of relative solvent accessibility (P = 0.0023);Gain of relative solvent accessibility (P = 0.0023);Gain of relative solvent accessibility (P = 0.0023);
MVP		0.53
ClinPred		0.011	T
GERP RS		-2.6
Varity_R		0.015
gMVP		0.080

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: rs1337416976; hg19: chr11-62457883;