20-17494136-C-G

Variant names:

• chr20-17494136-C-G
• rs145017887
• NM_001195.5:c.1936G>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001195.5(BFSP1):​c.1936G>C​(p.Val646Leu) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,816 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V646M) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BFSP1 NM_001195.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.55
• Publications: 3 publications found

Genes affected

BFSP1 (HGNC:1040): (beaded filament structural protein 1) This gene encodes a lens-specific intermediate filament-like protein named filensin. The encoded protein is expressed in lens fiber cells after differentiation has begun. This protein functions as a component of the beaded filament which is a cytoskeletal structure found in lens fiber cells. Mutations in this gene are the cause of autosomal recessive cortical juvenile-onset cataract. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

BFSP1 Gene-Disease associations (from GenCC):

• cataract 33

  Inheritance: AR, AD, SD Classification: STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• early-onset nuclear cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.30187887).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001195.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BFSP1	NM_001195.5	MANE Select	c.1936G>C	p.Val646Leu	missense	Exon 8 of 8	NP_001186.1	Q12934-1
	BFSP1	NM_001424338.1		c.1828G>C	p.Val610Leu	missense	Exon 7 of 7	NP_001411267.1
	BFSP1	NM_001278607.2		c.1603G>C	p.Val535Leu	missense	Exon 8 of 8	NP_001265536.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BFSP1	ENST00000377873.8	TSL:1 MANE Select	c.1936G>C	p.Val646Leu	missense	Exon 8 of 8	ENSP00000367104.3	Q12934-1
	BFSP1	ENST00000377868.6	TSL:1	c.1561G>C	p.Val521Leu	missense	Exon 8 of 8	ENSP00000367099.2	Q12934-2
	BFSP1	ENST00000929672.1		c.1828G>C	p.Val610Leu	missense	Exon 7 of 7	ENSP00000599731.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251350 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461816 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727212

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53382

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112000

Other (OTH) AF: 0.00 AC: 0 AN: 60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Benign	0.0061	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Benign	0.33	T
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.86	D
M_CAP	Uncertain	0.094	D
MetaRNN	Benign	0.30	T
MetaSVM	Benign	-0.30	T
MutationAssessor	Uncertain	2.5	M
PhyloP100		5.6
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-1.7	N
REVEL	Uncertain	0.32
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.36
MutPred		0.46		Gain of helix (P = 0.0854)
MVP		0.66
MPC		0.43
ClinPred		0.93	D
GERP RS		4.1
Varity_R		0.43
gMVP		0.39
Mutation Taster		=49/51	disease causing

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

Other links and lift over

dbSNP: rs145017887; hg19: chr20-17474781;