chr22-26599617-C-T

Position:

• chr22-26599617-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001887.4(CRYBB1):​c.632G>A​(p.Gly211Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CRYBB1 NM_001887.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.36

Genes affected

CRYBB1 (HGNC:2397): (crystallin beta B1) 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, undergoes extensive cleavage at its N-terminal extension during lens maturation. It is also a member of a gene cluster with beta-A4, beta-B2, and beta-B3. [provided by RefSeq, Jul 2008]

CRYBA4 (HGNC:2396): (crystallin beta A4) 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 acidic group member, is part of a gene cluster with beta-B1, beta-B2, and beta-B3. [provided by RefSeq, Jul 2008]

ENSG00000286326 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.977

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CRYBB1	NM_001887.4	c.632G>A	p.Gly211Asp	missense_variant	6/6	ENST00000647684.1	NP_001878.1
CRYBB1	XM_011529899.4	c.632G>A	p.Gly211Asp	missense_variant	6/6		XP_011528201.1
CRYBA4	XM_006724140.4	c.-239+2534C>T		intron_variant			XP_006724203.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CRYBB1	ENST00000647684.1	c.632G>A	p.Gly211Asp	missense_variant	6/6		NM_001887.4	ENSP00000497249.1
ENSG00000286326	ENST00000668614.1	n.56+2534C>T		intron_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 10, 2024

The c.632G>A (p.G211D) alteration is located in exon 6 (coding exon 5) of the CRYBB1 gene. This alteration results from a G to A substitution at nucleotide position 632, causing the glycine (G) at amino acid position 211 to be replaced by an aspartic acid (D). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.50
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D;D
Eigen	Uncertain	0.67
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.96	.;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Pathogenic	3.9	H;H
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-4.6	.;D
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0070	.;D
Sift4G	Uncertain	0.0040	.;D
Polyphen		1.0	D;D
Vest4		0.81
MutPred		0.83		Gain of solvent accessibility (P = 0.0281);Gain of solvent accessibility (P = 0.0281);
MVP		0.93
MPC		1.2
ClinPred		1.0	D
GERP RS		3.2
Varity_R		0.75
gMVP		0.82

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: rs1803712472; hg19: chr22-26995581;