rs752902567

Variant names:

• chr20-17494129-G-A
• rs752902567
• NM_001195.5:c.1943C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001195.5(BFSP1):​c.1943C>T​(p.Thr648Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,788 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T648A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: BFSP1 NM_001195.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.34
• Publications: 0 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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BFSP1	NM_001195.5	c.1943C>T	p.Thr648Ile	missense_variant	Exon 8 of 8	ENST00000377873.8	NP_001186.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BFSP1	ENST00000377873.8	c.1943C>T	p.Thr648Ile	missense_variant	Exon 8 of 8	1	NM_001195.5	ENSP00000367104.3
BFSP1	ENST00000377868.6	c.1568C>T	p.Thr523Ile	missense_variant	Exon 8 of 8	1		ENSP00000367099.2
BFSP1	ENST00000536626.7	c.1526C>T	p.Thr509Ile	missense_variant	Exon 9 of 9	2		ENSP00000442522.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 251314 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS 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: 0.00000274 AC: 4 AN: 1461788 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727188

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.0000895 AC: 4 AN: 44716

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: 86224

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53390

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111990

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000329 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 33 Uncertain:1

Feb 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. This variant has not been reported in the literature in individuals with BFSP1-related conditions. This sequence change replaces threonine with isoleucine at codon 648 of the BFSP1 protein (p.Thr648Ile). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and isoleucine. This variant is present in population databases (rs752902567, ExAC 0.03%). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Uncertain	0.098	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.66	D;.;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.85	T;T;T
M_CAP	Uncertain	0.19	D
MetaRNN	Uncertain	0.57	D;D;D
MetaSVM	Uncertain	-0.057	T
MutationAssessor	Uncertain	2.5	M;.;.
PhyloP100		7.3
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-3.2	D;D;D
REVEL	Uncertain	0.48
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;.;D
Polyphen		1.0	D;D;.
Vest4		0.51
MVP		0.89
MPC		0.44
ClinPred		0.96	D
GERP RS		5.0
Varity_R		0.60
gMVP		0.61
Mutation Taster		=21/79	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: rs752902567; hg19: chr20-17474774;