NM_001289808.2:c.40T>G

Variant names:

• chr11-111911685-A-C
• rs1555165595
• NM_001289808.2:c.40T>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_001289808.2(CRYAB):​c.40T>G​(p.Phe14Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. F14S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CRYAB NM_001289808.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.47
• Publications: 1 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.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_001289808.2
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRYAB	NM_001289808.2	c.40T>G	p.Phe14Val	missense_variant	Exon 1 of 3	ENST00000650687.2	NP_001276737.1
CRYAB	NM_001289807.1	c.40T>G	p.Phe14Val	missense_variant	Exon 2 of 4		NP_001276736.1
CRYAB	NM_001368245.1	c.40T>G	p.Phe14Val	missense_variant	Exon 2 of 4		NP_001355174.1
CRYAB	NM_001885.3	c.40T>G	p.Phe14Val	missense_variant	Exon 2 of 4		NP_001876.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRYAB	ENST00000650687.2	c.40T>G	p.Phe14Val	missense_variant	Exon 1 of 3		NM_001289808.2	ENSP00000499082.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dilated cardiomyopathy 1II Uncertain:1

Sep 27, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces phenylalanine with valine at codon 14 of the CRYAB protein (p.Phe14Val). The phenylalanine residue is moderately conserved and there is a small physicochemical difference between phenylalanine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CRYAB-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Uncertain	0.072	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.45	T;T;T;T;T;T;T;T;T;T;T
Eigen	Benign	0.17
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Benign	0.79	.;T;.;.;.;.;.;T;T;T;.
M_CAP	Benign	0.070	D
MetaRNN	Uncertain	0.73	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.097	D
MutationAssessor	Benign	1.7	L;L;L;L;L;L;.;.;.;.;.
PhyloP100		1.5
PrimateAI	Uncertain	0.61	T
PROVEAN	Benign	-1.4	N;.;N;N;N;N;N;N;N;N;N
REVEL	Uncertain	0.49
Sift	Benign	0.031	D;.;D;D;D;D;D;T;D;D;D
Sift4G	Benign	0.29	T;T;T;T;T;T;.;.;D;.;.
Polyphen		0.019	B;B;B;B;B;B;.;.;P;.;.
Vest4		0.32
MutPred		0.65		Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);Loss of stability (P = 0.1436);
MVP		0.95
MPC		0.69
ClinPred		0.90	D
GERP RS		5.1
PromoterAI		-0.022	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.62
gMVP		0.86
Mutation Taster		=77/23	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: rs1555165595; hg19: chr11-111782409;