SIX3
protein-codingSIX homeobox 3, the group of SINE class homeoboxes
Gene summary
This gene encodes a member of the sine oculis homeobox transcription factor family. The encoded protein plays a role in eye development. Mutations in this gene have been associated with holoprosencephaly type 2. [provided by RefSeq, Oct 2009]
- HPE2
MANE transcript
Inheritance
ClinVar variants
Top phenotype
gnomAD constraint
Max pathogenic AF
Genomic locus
External References & Databases
Transcript & Mutation Effects
hg38 • Region Span ~4.4 kbGenCC Phenotypes & Disease Associations
Curated gene-disease validity assertions and inheritance patterns
Inheritance Pattern: AD
Disease ID:MONDO:0007999
Submitter: Labcorp Genetics (formerly Invitae)
Inheritance Pattern: AD
Disease ID:MONDO:0007999
Submitter: PanelApp Australia
Inheritance Pattern: AD
Disease ID:MONDO:0007999
Submitter: G2P
Inheritance Pattern: AD
Disease ID:MONDO:0007999
Submitter: Laboratory for Molecular Medicine
This gene-disease relationship has undergone rapid assessment. Classifications are based on preliminary review of gene-disease validity during analysis of genomic sequencing results.
Clinical Genomic Database (CGD)
Manifestation: Craniofacial; Endocrine; Neurologic; Ophthalmologic
Intervention: General
Rationale: Genetic knowledge may be beneficial related to issues such as selection of optimal supportive care, informed medical decision-making, prognostic considerations, and avoidance of unnecessary testing
Comments: Variants in SIX3 have also been implicated in schizencephaly, but the data are unclear, and this may have co-occurred with typical holoprosencephaly-type malformations; Individuals with holoprosencephaly may demonstrate endocrine anomalies
ClinVar Associated Diseases & Phenotypes
Reported disease conditions connected to SIX3 variants in ClinVar
ClinVar Variants & Pathogenicity by Type
Statistics based on transcript NM_005413.4. Only rare variants are included.
We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.
Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.
| Effect | PathogenicP | Likely pathogenicLP | VUS | Likely benignLB | BenignB | Sum |
|---|---|---|---|---|---|---|
| synonymous | 5 | 73 | 1 | 79 | ||
| missense | 4 | 7 | 127 | 6 | 2 | 146 |
| nonsense | 6 | 2 | 8 | |||
| start loss | 1 | 1 | ||||
| frameshift | 9 | 5 | 1 | 15 | ||
| splice donor/acceptor (+/-2bp) | 1 | 1 | 2 | |||
| Total | 20 | 16 | 133 | 79 | 3 | 251 |
Highest pathogenic variant AF is 0.0000055398823
Transcript Catalog
Annotated transcript isoforms across RefSeq and Ensembl databases
| Transcript ID | Source | Protein ID | Coding Exons | MANE Status |
|---|---|---|---|---|
| RefSeq | NP_005404.1 | 2 | MANE Select | |
| Ensembl | ENSP00000260653.3 | 2 | MANE Select | |
| Ensembl | ENSP00000803069.1 | 2 | Standard |
Gene Ontology (GO) Annotations & Pathways
Biological processes, molecular functions, cellular components and pathways
Pathways ConsensusPathDB
- Preimplantation Embryo
Biological Process
- obsolete protein import into nucleus, translocation
- eye development
- epithelial cell maturation
- lens development in camera-type eye
- optic vesicle morphogenesis
Molecular Function
- transcription regulatory region sequence-specific DNA binding
- RNA polymerase II distal enhancer sequence-specific DNA binding
- DNA-binding transcription factor activity, RNA polymerase II-specific
- transcription corepressor binding
- DNA-binding transcription factor activity
Cellular Component
- nucleus
- transcription factor complex
gnomAD Constraint
Source:
- Gene type
- protein_coding
- Transcript type
- protein_coding
- Transcript
- ENST00000260653
- Coding exons
- 2
- Length
- 4315
- Individuals with no LoFs
- 117557
- Homozygous LoFs
- 0
- Heterozygous LoFs
- 2
- Defined
- 117559
- p
- 0.00000851
| Z-Score | Observed | Expected | Observed/Expected | Mutation Rate | Total Possible | |
|---|---|---|---|---|---|---|
| Missense | 2.07 | 119 | 202 | 0.589 | 0.00000935 | 2093 |
| Missense (PolyPhen) | 22 | 66.481 | 0.33092 | 684 | ||
| Synonymous | -1.87 | 112 | 89.5 | 1.25 | 0.00000429 | 691 |
| Loss of Function | 2.82 | 0 | 9.27 | 0.00 | 4.01e-7 | 98 |
Population LoF Frequency
| Population | CAF | p-value | Status |
|---|---|---|---|
| African | 0 | 0.0 | absent |
| Latino/Admixed American | 0.000058 | 0.000058 | rare |
| Ashkenazi Jewish | 0 | 0.0 | absent |
| East Asian | 0 | 0.0 | absent |
| Finnish | 0 | 0.0 | absent |
| European (Non-Finnish) | 0 | 0.0 | absent |
| South Asian | 0 | 0.0 | absent |
| Other | 0 | 0.0 | absent |
dbNSFP Gene Annotations
Source:
- Function
- FUNCTION: Transcriptional regulator which can act as both a transcriptional repressor and activator by binding a ATTA homeodomain core recognition sequence on these target genes. During forebrain development represses WNT1 expression allowing zona limitans intrathalamica formation and thereby ensuring proper anterio-posterior patterning of the diencephalon and formation of the rostral diencephalon. Acts as a direct upstream activator of SHH expression in the rostral diencephalon ventral midline and that in turn SHH maintains its expression. In addition, Six3 activity is required for the formation of the telencephalon. During postnatal stages of brain development is necessary for ependymal cell maturation by promoting the maturation of radial glia into ependymal cells through regulation of neuroblast proliferation and migration. Acts on the proliferation and differentiation of neural progenitor cells through activating transcription of CCND1 AND CCND2. During early lens formation plays a role in lens induction and specification by activating directly PAX6 in the presumptive lens ectoderm. In turn PAX6 activates SIX3 resulting in activation of PDGFRA and CCND1 promoting cell proliferation. Also is required for the neuroretina development by directly suppressing WNT8B expression in the anterior neural plate territory. Its action during retina development and lens morphogenesis is AES and TLE4-dependent manner. Furthermore, during eye development regulates several genes expression. Before and during early lens development represses the CRYGF promoter by binding a SIX repressor element. Directly activates RHO transcription, or cooperates with CRX or NRL. Six3 functions also in the formation of the proximodistal axis of the optic cup, and promotes the formation of optic vesicles-like structures. During pituitary development, acts in parallel or alternatively with HESX1 to control cell proliferation through Wnt/beta-catenin pathway (By similarity). Plays a role in eye development by suppressing WNT1 expression and in dorsal- ventral patterning by repressing BMP signaling pathway. {ECO:0000250|UniProtKB:Q62233, ECO:0000269|PubMed:18791198}.;
- Disease
- DISEASE: Holoprosencephaly 2 (HPE2) [MIM:157170]: A structural anomaly of the brain, in which the developing forebrain fails to correctly separate into right and left hemispheres. Holoprosencephaly is genetically heterogeneous and associated with several distinct facies and phenotypic variability. {ECO:0000269|PubMed:10369266, ECO:0000269|PubMed:15221788, ECO:0000269|PubMed:15523651, ECO:0000269|PubMed:17001667, ECO:0000269|PubMed:18791198, ECO:0000269|PubMed:20531442}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Schizencephaly (SCHZC) [MIM:269160]: Extremely rare human congenital disorder characterized by a full-thickness cleft within the cerebral hemispheres. These clefts are lined with gray matter and most commonly involve the parasylvian regions. Large portions of the cerebral hemispheres may be absent and replaced by cerebro- spinal fluid. {ECO:0000269|PubMed:20157829}. Note=The disease is caused by mutations affecting the gene represented in this entry.;
Recessive Scores
- pRec
- 0.218
Intolerance Scores
- LoFtool
- 0.0812
- RVIS EVS
- 0.06
- RVIS percentile EVS
- 58.26
Essentials
- Essential (CRISPR)
- N
- Essential (CRISPR2)
- N
- Essential (gene trap)
- N
- Indispensability pred.
- E
- Indispensability score
- 0.958
Gene Damage Prediction
| All | Recessive | Dominant | |
|---|---|---|---|
| Mendelian | Medium | Medium | Medium |
| Primary Immunodeficiency | Medium | Medium | Medium |
| Cancer | Medium | Medium | Medium |