12-56453118-C-A

Variant names:

• chr12-56453118-C-A
• rs759746926
• NM_012064.4:c.560G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_012064.4(MIP):​c.560G>T​(p.Arg187Leu) 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. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MIP NM_012064.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.57
• Publications: 0 publications found

Genes affected

MIP (HGNC:7103): (major intrinsic protein of lens fiber) Major intrinsic protein is a member of the water-transporting aquaporins as well as the original member of the MIP family of channel proteins. The function of the fiber cell membrane protein encoded by this gene is undetermined, yet this protein is speculated to play a role in intracellular communication. The MIP protein is expressed in the ocular lens and is required for correct lens function. This gene has been mapped among aquaporins AQP2, AQP5, and AQP6, in a potential gene cluster at 12q13. [provided by RefSeq, Jul 2008]

MIP Gene-Disease associations (from GenCC):

• cataract 15 multiple types

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• cerulean cataract

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

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000285528 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MIP	NM_012064.4	c.560G>T	p.Arg187Leu	missense_variant	Exon 3 of 4	ENST00000652304.1	NP_036196.1
MIP	XM_011538354.2	c.275G>T	p.Arg92Leu	missense_variant	Exon 5 of 6		XP_011536656.1
MIP	XM_017019306.2	c.203G>T	p.Arg68Leu	missense_variant	Exon 3 of 4		XP_016874795.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MIP	ENST00000652304.1	c.560G>T	p.Arg187Leu	missense_variant	Exon 3 of 4		NM_012064.4	ENSP00000498622.1
ENSG00000285528	ENST00000648304.1	n.*184G>T		non_coding_transcript_exon_variant	Exon 3 of 4			ENSP00000497190.1
ENSG00000285528	ENST00000648304.1	n.*184G>T		3_prime_UTR_variant	Exon 3 of 4			ENSP00000497190.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 15 multiple types Uncertain:1

Sep 29, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a MIP-related disease. This sequence change replaces arginine with leucine at codon 187 of the MIP protein (p.Arg187Leu). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.8	H
PhyloP100		7.6
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.94		Loss of methylation at R187 (P = 0.0227);
MVP		0.95
MPC		1.4
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.93
Mutation Taster		=9/91	disease causing

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: rs759746926; hg19: chr12-56846902; COSMIC: COSV99234283; COSMIC: COSV99234283;