rs1553922891

Variant names:

• chr4-110621213-G-GT
• rs1553922891
• NM_000325.6:c.361dupA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000325.6(PITX2):​c.361dupA​(p.Thr121AsnfsTer131) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: PITX2 NM_000325.6 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.20
• Publications: 0 publications found

Genes affected

PITX2 (HGNC:9005): (paired like homeodomain 2) This gene encodes a member of the RIEG/PITX homeobox family, which is in the bicoid class of homeodomain proteins. The encoded protein acts as a transcription factor and regulates procollagen lysyl hydroxylase gene expression. This protein plays a role in the terminal differentiation of somatotroph and lactotroph cell phenotypes, is involved in the development of the eye, tooth and abdominal organs, and acts as a transcriptional regulator involved in basal and hormone-regulated activity of prolactin. Mutations in this gene are associated with Axenfeld-Rieger syndrome, iridogoniodysgenesis syndrome, and sporadic cases of Peters anomaly. A similar protein in other vertebrates is involved in the determination of left-right asymmetry during development. Alternatively spliced transcript variants encoding distinct isoforms have been described. [provided by RefSeq, Jul 2008]

PITX2 Gene-Disease associations (from GenCC):

• anterior segment dysgenesis 4

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• Axenfeld-Rieger syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• ring dermoid of cornea

  Inheritance: Unknown, AD Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet
• aniridia

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• Axenfeld anomaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Axenfeld-Rieger syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial atrial fibrillation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Rieger anomaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Peters anomaly

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

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 45 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-110621213-G-GT is Pathogenic according to our data. Variant chr4-110621213-G-GT is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 474010.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PITX2	NM_000325.6	c.361dupA	p.Thr121AsnfsTer131	frameshift_variant	Exon 2 of 3	ENST00000644743.1	NP_000316.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PITX2	ENST00000644743.1	c.361dupA	p.Thr121AsnfsTer131	frameshift_variant	Exon 2 of 3		NM_000325.6	ENSP00000495061.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Anterior segment dysgenesis 4;C3714873:Axenfeld-Rieger syndrome type 1 Pathogenic:1

Jul 06, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals with PITX2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change results in a premature translational stop signal in the PITX2 gene (p.Thr68Asnfs*131). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 204 amino acids of the PITX2 protein. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant is expected to disrupt the functionally conserved OAR or aristaless domain, which is located in the final 39 amino acids of the PITX2 protein. This domain mediates the interaction with a number of proteins that are required for PITX2 transcriptional transactivation activity (PMID: 10490637, 18045789, 15728254). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		6.2

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: rs1553922891; hg19: chr4-111542369;