22-25201421-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4 BS1_Supporting

The NM_004076.5(CRYBB3):c.25G>A(p.Glu9Lys) variant causes a missense change. The variant allele was found at a frequency of 0.0000273 in 1,613,252 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000099 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000020 (0 hom.)
• Consequence: CRYBB3 NM_004076.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.47

Genes affected

CRYBB3 (HGNC:2400): (crystallin beta B3) Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B2. Mutations in this gene result in cataract congenital nuclear autosomal recessive type 2. [provided by RefSeq, Feb 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.41294718).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0000986 (15/152090) while in subpopulation AFR AF= 0.000266 (11/41402). AF 95% confidence interval is 0.000149. There are 0 homozygotes in gnomad4. There are 7 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRYBB3	NM_004076.5	c.25G>A	p.Glu9Lys	missense_variant	2/6	ENST00000215855.7
CRYBB3	XM_047441147.1	c.25G>A	p.Glu9Lys	missense_variant	1/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRYBB3	ENST00000215855.7	c.25G>A	p.Glu9Lys	missense_variant	2/6	1	NM_004076.5	P1
CRYBB3	ENST00000404334.1	c.25G>A	p.Glu9Lys	missense_variant	2/5	3

Frequencies

GnomAD3 genomes AF: 0.0000986 AC: 15 AN: 152090 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000266

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 251398 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135896

Gnomad AFR exome AF: 0.000123

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000198 AC: 29 AN: 1461162 Hom.: 0 Cov.: 34 AF XY: 0.0000193 AC XY: 14 AN XY: 726906

Gnomad4 AFR exome AF: 0.000149

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000162

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000986 AC: 15 AN: 152090 Hom.: 0 Cov.: 32 AF XY: 0.0000942 AC XY: 7 AN XY: 74302

Gnomad4 AFR AF: 0.000266

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000444 Hom.: 0

Bravo AF: 0.0000907

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 22 multiple types Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.19
Cadd	Benign	22
Dann	Uncertain	1.0
DEOGEN2	Benign	0.025	T;T
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.22
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.84	T;T
M_CAP	Benign	0.044	D
MetaRNN	Benign	0.41	T;T
MetaSVM	Benign	-0.81	T
MutationAssessor	Uncertain	2.2	M;.
MutationTaster	Benign	0.98	D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.91	N;N
REVEL	Uncertain	0.31
Sift	Benign	0.16	T;D
Sift4G	Benign	0.69	T;T
Polyphen		0.22	B;.
Vest4		0.62
MVP		0.60
MPC		0.26
ClinPred		0.23	T
GERP RS		2.6
Varity_R		0.084
gMVP		0.46

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: rs367616021; hg19: chr22-25597388; COSMIC: COSV53195509; COSMIC: COSV53195509;