NM_001289808.2:c.149G>C

Variant names:

• chr11-111911576-C-G
• rs781846534
• NM_001289808.2:c.149G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001289808.2(CRYAB):​c.149G>C​(p.Arg50Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,460,974 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. R50W) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CRYAB NM_001289808.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.43
• Publications: 0 publications found

Genes affected

CRYAB (HGNC:2389): (crystallin alpha B) Mammalian lens crystallins are divided into alpha, beta, and gamma families. Alpha crystallins are composed of two gene products: alpha-A and alpha-B, for acidic and basic, respectively. Alpha crystallins can be induced by heat shock and are members of the small heat shock protein (HSP20) family. They act as molecular chaperones although they do not renature proteins and release them in the fashion of a true chaperone; instead they hold them in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional functions of alpha crystallins are an autokinase activity and participation in the intracellular architecture. The encoded protein has been identified as a moonlighting protein based on its ability to perform mechanistically distinct functions. Alpha-A and alpha-B gene products are differentially expressed; alpha-A is preferentially restricted to the lens and alpha-B is expressed widely in many tissues and organs. Elevated expression of alpha-B crystallin occurs in many neurological diseases; a missense mutation cosegregated in a family with a desmin-related myopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2019]

CRYAB Gene-Disease associations (from GenCC):

• myofibrillar myopathy 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Orphanet
• cataract 16 multiple types

  Inheritance: AD, AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P
• fatal infantile hypertonic myofibrillar myopathy

  Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, Orphanet
• early-onset lamellar cataract

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

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy 1II

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

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

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.904

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001289808.2. 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
	CRYAB	NM_001289808.2	MANE Select	c.149G>C	p.Arg50Pro	missense	Exon 1 of 3	NP_001276737.1
	CRYAB	NM_001289807.1		c.149G>C	p.Arg50Pro	missense	Exon 2 of 4	NP_001276736.1
	CRYAB	NM_001368245.1		c.149G>C	p.Arg50Pro	missense	Exon 2 of 4	NP_001355174.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRYAB	ENST00000650687.2	MANE Select	c.149G>C	p.Arg50Pro	missense	Exon 1 of 3	ENSP00000499082.1
	CRYAB	ENST00000526180.6	TSL:1	c.149G>C	p.Arg50Pro	missense	Exon 2 of 4	ENSP00000436051.1
	CRYAB	ENST00000227251.7	TSL:5	c.149G>C	p.Arg50Pro	missense	Exon 2 of 4	ENSP00000227251.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1460974 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726650

⚠️ 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: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44602

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26074

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 85922

European-Finnish (FIN) AF: 0.0000188 AC: 1 AN: 53316

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111766

Other (OTH) AF: 0.00 AC: 0 AN: 60376

⚠️ 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.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	0.71
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Benign	0.75	D
LIST_S2	Benign	0.80	T
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.90	D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		1.4
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-3.4	D
REVEL	Pathogenic	0.67
Sift	Uncertain	0.025	D
Sift4G	Uncertain	0.031	D
Polyphen		1.0	D
Vest4		0.24
MutPred		0.74		Gain of glycosylation at R50 (P = 0.0179)
MVP		0.99
MPC		0.81
ClinPred		0.99	D
GERP RS		5.6
PromoterAI		0.034	Neutral
Varity_R		0.98
gMVP		0.86
Mutation Taster		=70/30	polymorphism

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: rs781846534; hg19: chr11-111782300;