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| Mendeliome v0.8741 | TCF7L2 |
Zornitza Stark changed review comment from: 2 reviews Konstantinos Varvagiannis (Other) I don't know Dias et al (2021 - PMID: 34003604) describe the phenotype of 11 unrelated individuals harboring de novo missense/truncating TCF7L2 variants. Features included DD in childhood (motor delay in 8/11, speech delay in 11/11), intellectual abilities ranging from average cognitive functioning to mild/moderate ID (the latter observed in 5/11), myopia (6/11) , dysmorphic features, variable orthopedic findings, and neuropsychiatric comorbidities incl. ASD (4/11) / ADHD (4/11). One additional (12th) individual was excluded from this summary due to concurrent diagnosis of hypoxic-ischemic injury. TCF7L2 on 10q25 encodes transcription factor 7-like 2, a high mobility group (HMG) box-containing transcription factor. As the authors discuss, the protein mediates canonical Wnt signaling. Secreted Wnt proteins lead to release of beta-catenin (CTNNB1) which after translocation to the nucleus acts with DNA-binding factors incl. TCF7L2 to turn on Wnt-responsive target genes. As a result TCF7L2 acts with beta-catenin as a switch for transcriptional regulation. Multiple alternative spliced TCF7L2 transcripts mediate it's function and specificity of transcriptional repertoire in a variety of tissues and contexts. Dias et al provide references for its role in nervous system development incl. neurogenesis and thalamic development. Variants in all cases occurred as de novo events with pLoF (stopgain, frameshift, splicing) ones predicted to lead to NMD. Missense variants occurred in all cases in or adjacent to the HMG box domain [aa 350-417]. 5 different missense variants affecting 3 residues were reported incl. c.1142A>C, c.1143C>G (leading to Asn381Thr/Lys respectively), c.1250G>T (Trp417Leu), c.1267T>C, c.1268A>G (leading to Tyr423His/Cys) [NM_001146274.1]. The gene has a pLI of 0.99-1 gnomAD/ExAC while there is a region of missense constraint encompassing the HMG box domain (the latter is an evolutionary conserved region mediating interactions with DNA). No phenotypic differences were observed among individuals with pLoF and missense SNVs, and haploinsufficiency is presumed to be the underlying mechanism. There are no variant or other studies performed, nor any animal models discussed. In supplementary table 2, the authors provide several references to previous large scale sequencing studies with brief/incomplete descriptions of individuals de novo TCF7L2 variants and neurodevelopmental disorder (ID/ASD - Iossifov, De Rubeis, Lelieveld, McRae/DDD study and many other Refs). Heterozygous TCF7L2 variants are thought to confer susceptibility to type diabetes mellitus (MIM 125853). Individuals reported by Dias et al did not have endocrine abnormalities including DM. A study by Roychowdhury et al (2021 - PMID: 34265237) suggests that regulatory variants in TCF7L2 are associated with thoracic aneurysm. There is no other associated phenotype (notably NDD) in OMIM. G2P includes TCF7L2 in its DD panel (Disease : TC7L2-related DD, Confidence:confirmed, Monoallelic, LoF). SysID includes this gene within the autism candidate genes and current primary ID genes.; to: Dias et al (2021 - PMID: 34003604) describe the phenotype of 11 unrelated individuals harboring de novo missense/truncating TCF7L2 variants. Features included DD in childhood (motor delay in 8/11, speech delay in 11/11), intellectual abilities ranging from average cognitive functioning to mild/moderate ID (the latter observed in 5/11), myopia (6/11) , dysmorphic features, variable orthopedic findings, and neuropsychiatric comorbidities incl. ASD (4/11) / ADHD (4/11). One additional (12th) individual was excluded from this summary due to concurrent diagnosis of hypoxic-ischemic injury. TCF7L2 on 10q25 encodes transcription factor 7-like 2, a high mobility group (HMG) box-containing transcription factor. As the authors discuss, the protein mediates canonical Wnt signaling. Secreted Wnt proteins lead to release of beta-catenin (CTNNB1) which after translocation to the nucleus acts with DNA-binding factors incl. TCF7L2 to turn on Wnt-responsive target genes. As a result TCF7L2 acts with beta-catenin as a switch for transcriptional regulation. Multiple alternative spliced TCF7L2 transcripts mediate it's function and specificity of transcriptional repertoire in a variety of tissues and contexts. Dias et al provide references for its role in nervous system development incl. neurogenesis and thalamic development. Variants in all cases occurred as de novo events with pLoF (stopgain, frameshift, splicing) ones predicted to lead to NMD. Missense variants occurred in all cases in or adjacent to the HMG box domain [aa 350-417]. 5 different missense variants affecting 3 residues were reported incl. c.1142A>C, c.1143C>G (leading to Asn381Thr/Lys respectively), c.1250G>T (Trp417Leu), c.1267T>C, c.1268A>G (leading to Tyr423His/Cys) [NM_001146274.1]. The gene has a pLI of 0.99-1 gnomAD/ExAC while there is a region of missense constraint encompassing the HMG box domain (the latter is an evolutionary conserved region mediating interactions with DNA). No phenotypic differences were observed among individuals with pLoF and missense SNVs, and haploinsufficiency is presumed to be the underlying mechanism. There are no variant or other studies performed, nor any animal models discussed. In supplementary table 2, the authors provide several references to previous large scale sequencing studies with brief/incomplete descriptions of individuals de novo TCF7L2 variants and neurodevelopmental disorder (ID/ASD - Iossifov, De Rubeis, Lelieveld, McRae/DDD study and many other Refs). Heterozygous TCF7L2 variants are thought to confer susceptibility to type diabetes mellitus (MIM 125853). Individuals reported by Dias et al did not have endocrine abnormalities including DM. A study by Roychowdhury et al (2021 - PMID: 34265237) suggests that regulatory variants in TCF7L2 are associated with thoracic aneurysm. There is no other associated phenotype (notably NDD) in OMIM. G2P includes TCF7L2 in its DD panel (Disease : TC7L2-related DD, Confidence:confirmed, Monoallelic, LoF). SysID includes this gene within the autism candidate genes and current primary ID genes. |
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| Mendeliome v0.1718 | CTNNB1 | Zornitza Stark Marked gene: CTNNB1 as ready | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1718 | CTNNB1 | Zornitza Stark Gene: ctnnb1 has been classified as Green List (High Evidence). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1718 | CTNNB1 | Zornitza Stark Phenotypes for gene: CTNNB1 were changed from to Exudative vitreoretinopathy 7, MIM# 617572; Neurodevelopmental disorder with spastic diplegia and visual defects, MIM# 615075 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1717 | CTNNB1 | Zornitza Stark Publications for gene: CTNNB1 were set to | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1716 | CTNNB1 | Zornitza Stark Mode of pathogenicity for gene: CTNNB1 was changed from to Other | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1715 | CTNNB1 | Zornitza Stark Mode of inheritance for gene: CTNNB1 was changed from Unknown to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1714 | CTNNB1 | Zornitza Stark reviewed gene: CTNNB1: Rating: GREEN; Mode of pathogenicity: None; Publications: 25326669, 29435196, 27915094, 30640974; Phenotypes: Exudative vitreoretinopathy 7, MIM# 617572, Neurodevelopmental disorder with spastic diplegia and visual defects, MIM# 615075; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.1714 | CTNNB1 |
Teresa Zhao changed review comment from: OMIM: LoF - mainly non cancerous phenotypes, and GoF - mainly cancer phenotypes. Cancer hot spot in exon 3, mainly missenses affecting S33, S37, S45, T41, D32 and G34 (Gao. C. et al. 2017); to: OMIM: LoF - mainly non cancerous phenotypes, and GoF - mainly cancer phenotypes. Cancer hot spot in exon 3, mainly missenses affecting S33, S37, S45, T41, D32 and G34 (Gao. C. et al. 2017) |
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| Mendeliome v0.1714 | CTNNB1 | Teresa Zhao reviewed gene: CTNNB1: Rating: GREEN; Mode of pathogenicity: Other; Publications: ; Phenotypes: PMID: 29435196, PMID: 27915094, PMID: 30640974; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mendeliome v0.0 | CTNNB1 |
Zornitza Stark gene: CTNNB1 was added gene: CTNNB1 was added to Mendeliome_VCGS. Sources: Expert Review Green,Victorian Clinical Genetics Services Mode of inheritance for gene: CTNNB1 was set to Unknown |
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