chr22-26599492-A-G

Variant names:

• chr22-26599492-A-G
• rs1114167432
• NM_001887.4:c.757T>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PM4

The NM_001887.4(CRYBB1):​c.757T>C​(p.Ter253Argext*?) variant causes a stop lost change. The variant allele was found at a frequency of 0.000000685 in 1,459,814 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CRYBB1 NM_001887.4 stop_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 3.87
• Publications: 10 publications found

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]

ENSG00000286326 (HGNC:):

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]

CRYBA4 Gene-Disease associations (from GenCC):

• cataract 23

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• cataract - microcornea syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset lamellar cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Stoplost variant in NM_001887.4 Downstream stopcodon found after 42 codons.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001887.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRYBB1	NM_001887.4	MANE Select	c.757T>C	p.Ter253Argext*?	stop_lost	Exon 6 of 6	NP_001878.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRYBB1	ENST00000647684.1	MANE Select	c.757T>C	p.Ter253Argext*?	stop_lost	Exon 6 of 6	ENSP00000497249.1
	ENSG00000286326	ENST00000668614.2		n.252+2409A>G		intron	N/A
	ENSG00000286326	ENST00000840228.1		n.185+2409A>G		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459814 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726174

African (AFR) AF: 0.00 AC: 0 AN: 33430

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26088

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

South Asian (SAS) AF: 0.00 AC: 0 AN: 86190

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53364

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4620

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111478

Other (OTH) AF: 0.00 AC: 0 AN: 60246

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 17 multiple types Pathogenic:1 Uncertain:1

Jul 28, 2023

Molecular Medicine, University of Pavia

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

Jun 05, 2017

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.060	T
BayesDel_noAF	Benign	-0.15
CADD	Benign	17
DANN	Benign	0.85
Eigen	Pathogenic	0.77
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Uncertain	0.89	D
PhyloP100		3.9
Vest4		0.042
GERP RS		4.2
Mutation Taster		=80/20	disease causing (ClinVar)

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: rs1114167432; hg19: chr22-26995456;