Barber Say syndrome | |
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Other names | Hypertrichosis-atrophic skin-ectropion-macrostomia syndrome |
Barber-Say syndrome has an autosomal dominant pattern of inheritance | |
Usual onset | Neonatal |
Barber-Say syndrome (BSS) is a very rare congenital disorder associated with excessive hair growth (hypertrichosis), fragile (atrophic) skin, eyelid deformities (ectropion), and an overly broad mouth (macrostomia). [1]
Barber-Say syndrome is phenotypically similar to Ablepharon macrostomia syndrome, which is also associated with dominant mutations in TWIST2. [2]
Multiple cases of parent-to-child transmission suggest that Barber-Say syndrome exhibits autosomal dominant inheritance. [3] Exome sequencing and expression studies have shown that BSS is caused by mutations in the TWIST2 gene that affect a highly conserved residue of TWIST2 (twist-related protein 2). TWIST2 is a basic helix-loop-helix transcription factor that binds to E-box DNA motifs (5'-CANNTG-3') as a heterodimer and inhibits transcriptional activation. [4] Because TWIST2 mediates mesenchymal stem cell differentiation [5] and prevents premature or ectopic osteoblast differentiation, [6] mutations in TWIST2 that disrupt these functions by altering DNA-binding activity could explain many of the phenotypes of BSS. [2]
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The prevalence of Barber Say syndrome is less than 1 in 1,000,000. [7] As of 2017, only 15 cases have been reported in the literature. [8]
Saethre–Chotzen syndrome (SCS), also known as acrocephalosyndactyly type III, is a rare congenital disorder associated with craniosynostosis. This affects the shape of the head and face, resulting in a cone-shaped head and an asymmetrical face. Individuals with SCS also have droopy eyelids (ptosis), widely spaced eyes (hypertelorism), and minor abnormalities of the hands and feet (syndactyly). Individuals with more severe cases of SCS may have mild to moderate intellectual or learning disabilities. Depending on the level of severity, some individuals with SCS may require some form of medical or surgical intervention. Most individuals with SCS live fairly normal lives, regardless of whether medical treatment is needed or not.
GATA-binding factor 1 or GATA-1 is the founding member of the GATA family of transcription factors. This protein is widely expressed throughout vertebrate species. In humans and mice, it is encoded by the GATA1 and Gata1 genes, respectively. These genes are located on the X chromosome in both species.
Forkhead box protein C2 (FOXC2) also known as forkhead-related protein FKHL14 (FKHL14), transcription factor FKH-14, or mesenchyme fork head protein 1 (MFH1) is a protein that in humans is encoded by the FOXC2 gene. FOXC2 is a member of the fork head box (FOX) family of transcription factors.
Twist-related protein 1 (TWIST1) also known as class A basic helix–loop–helix protein 38 (bHLHa38) is a basic helix-loop-helix transcription factor that in humans is encoded by the TWIST1 gene.
Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the MITF gene.
Hay–Wells syndrome is one of at least 150 known types of ectodermal dysplasia. These disorders affect tissues that arise from the ectodermal germ layer, such as skin, hair, and nails.
Ablepharon macrostomia syndrome (AMS) is an extremely rare, autosomal dominant genetic disorder characterized by abnormal phenotypic appearances that primarily affect the head and face as well as the skull, skin, fingers and genitals. AMS generally results in abnormal ectoderm-derived structures. The most prominent abnormality is the underdevelopment (microblepharon) or absence of eyelids – signifying the ablepharon aspect of the disease – and a wide, fish-like mouth – macrostomia. Infants presenting with AMS may also have malformations of the abdominal wall and nipples. Children with AMS might also experience issues with learning development, language difficulties and intellectual disabilities.
Transcription factor 4 (TCF-4) also known as immunoglobulin transcription factor 2 (ITF-2) is a protein that in humans is encoded by the TCF4 gene located on chromosome 18q21.2.
Forkhead box C1, also known as FOXC1, is a protein which in humans is encoded by the FOXC1 gene.
Forkhead box protein L2 is a protein that in humans is encoded by the FOXL2 gene.
Transcription factor HES1 is a protein that is encoded by the Hes1 gene, and is the mammalian homolog of the hairy gene in Drosophila. HES1 is one of the seven members of the Hes gene family (HES1-7). Hes genes code nuclear proteins that suppress transcription.
Single-minded homolog 2 is a protein that in humans is encoded by the SIM2 gene. It plays a major role in the development of the central nervous system midline as well as the construction of the face and head.
ID4 is a protein coding gene. In humans, it encodes for the protein known as DNA-binding protein inhibitor ID-4. This protein is known to be involved in the regulation of many cellular processes during both prenatal development and tumorigenesis. This is inclusive of embryonic cellular growth, senescence, cellular differentiation, apoptosis, and as an oncogene in angiogenesis.
Heart- and neural crest derivatives-expressed protein 1 is a protein that in humans is encoded by the HAND1 gene.
Twist-related protein 2 is a protein that in humans is encoded by the TWIST2 gene. The protein encoded by this gene is a basic helix-loop-helix (bHLH) transcription factor and shares similarity with another bHLH transcription factor, TWIST1. bHLH transcription factors have been implicated in cell lineage determination and differentiation. It is thought that during osteoblast development, this protein may inhibit osteoblast maturation and maintain cells in a preosteoblast phenotype.
POU domain, class 3, transcription factor 4 is a protein that in humans is encoded by the POU3F4 gene found on the X chromosome.
FG syndrome (FGS) is a rare genetic syndrome caused by one or more recessive genes located on the X chromosome and causing physical anomalies and developmental delays. FG syndrome was named after the first letters of the surnames of the first patients noted with the disease. First reported by American geneticists John M. Opitz and Elisabeth G. Kaveggia in 1974, its major clinical features include intellectual disability, hyperactivity, hypotonia, and a characteristic facial appearance including macrocephaly.
Macrostomia refers to a mouth that is unusually wide. The term is from the Greek prefix makro- meaning "large" and from Greek στόμα, "mouth".
Branchio-oculo-facial syndrome (BOFS) is a disease that arises from a mutation in the TFAP2A gene. It is a rare autosomal dominant disorder that starts to affect a child's development before birth. Symptoms of this condition include skin abnormalities on the neck, deformities of the ears and eyes, and other distinctive facial features such a cleft lip along with slow growth, mental retardation and premature graying of hair.
(HES7) or bHLHb37 is protein coding mammalian gene found on chromosome 17 in humans. HES7 is a member of the Hairy and Enhancer of Split families of Basic helix-loop-helix proteins. The gene product is a transcription factor and is expressed cyclically in the presomitic mesoderm as part of the Notch signalling pathway. HES7 is involved in the segmentation of somites from the presomitic mesoderm in vertebrates. The HES7 gene is self-regulated by a negative feedback loop in which the gene product can bind to its own promoter. This causes the gene to be expressed in an oscillatory manner. The HES7 protein also represses expression of Lunatic Fringe (LFNG) thereby both directly and indirectly regulating the Notch signalling pathway. Mutations in HES7 can result in deformities of the spine, ribs and heart. Spondylocostal dysostosis is a common disease caused by mutations in the HES7 gene. The inheritance pattern of Spondylocostal dysostosis is autosomal recessive.