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Genes Sep 2021Treacher Collins syndrome (TCS) is associated with abnormal differentiation of the first and second pharyngeal arches, occurring during fetal development. Features of... (Review)
Review
Treacher Collins syndrome (TCS) is associated with abnormal differentiation of the first and second pharyngeal arches, occurring during fetal development. Features of TCS include microtia with conductive hearing loss, slanting palpebral fissures with possibly coloboma of the lateral part of lower eyelids, midface hypoplasia, micrognathia as well as sporadically cleft palate and choanal atresia or stenosis. TCS occurs in the general population at a frequency of 1 in 50,000 live births. Four subtypes of Treacher Collins syndrome exist. TCS can be caused by pathogenic variants in the , , and genes. Genetically, the gene contains 27 exons which encodes the Treacle protein. In , over 200 pathogenic variants have been identified, of which most are deletions leading to a frame-shift, that result in the formation of a termination codon. In the presented article, we review the genetics and phenotype of TCS as well as the management and surgical procedures utilized for treatment.
Topics: Choanal Atresia; DNA-Directed RNA Polymerases; Humans; Mandibulofacial Dysostosis; Nuclear Proteins; Phosphoproteins; Syndrome
PubMed: 34573374
DOI: 10.3390/genes12091392 -
Journal of Medical Genetics May 2022Oculo-auriculo-vertebral spectrum (OAVS) or Goldenhar syndrome is due to an abnormal development of first and second branchial arches derivatives during embryogenesis... (Review)
Review
Oculo-auriculo-vertebral spectrum (OAVS) or Goldenhar syndrome is due to an abnormal development of first and second branchial arches derivatives during embryogenesis and is characterised by hemifacial microsomia associated with auricular, ocular and vertebral malformations. The clinical and genetic heterogeneity of this spectrum with incomplete penetrance and variable expressivity, render its molecular diagnosis difficult. Only a few recurrent CNVs and genes have been identified as causatives in this complex disorder so far. Prenatal environmental causal factors have also been hypothesised. However, most of the patients remain without aetiology. In this review, we aim at updating clinical diagnostic criteria and describing genetic and non-genetic aetiologies, animal models as well as novel diagnostic tools and surgical management, in order to help and improve clinical care and genetic counselling of these patients and their families.
Topics: Animals; Branchial Region; DNA Copy Number Variations; Goldenhar Syndrome; Humans
PubMed: 35110414
DOI: 10.1136/jmedgenet-2021-108219 -
Nature Communications Apr 2023Craniofacial microsomia (CFM; also known as Goldenhar syndrome), is a craniofacial developmental disorder of variable expressivity and severity with a recognizable set...
Craniofacial microsomia (CFM; also known as Goldenhar syndrome), is a craniofacial developmental disorder of variable expressivity and severity with a recognizable set of abnormalities. These birth defects are associated with structures derived from the first and second pharyngeal arches, can occur unilaterally and include ear dysplasia, microtia, preauricular tags and pits, facial asymmetry and other malformations. The inheritance pattern is controversial, and the molecular etiology of this syndrome is largely unknown. A total of 670 patients belonging to unrelated pedigrees with European and Chinese ancestry with CFM, are investigated. We identify 18 likely pathogenic variants in 21 probands (3.1%) in FOXI3. Biochemical experiments on transcriptional activity and subcellular localization of the likely pathogenic FOXI3 variants, and knock-in mouse studies strongly support the involvement of FOXI3 in CFM. Our findings indicate autosomal dominant inheritance with reduced penetrance, and/or autosomal recessive inheritance. The phenotypic expression of the FOXI3 variants is variable. The penetrance of the likely pathogenic variants in the seemingly dominant form is reduced, since a considerable number of such variants in affected individuals were inherited from non-affected parents. Here we provide suggestive evidence that common variation in the FOXI3 allele in trans with the pathogenic variant could modify the phenotypic severity and accounts for the incomplete penetrance.
Topics: Animals; Mice; Goldenhar Syndrome; Facial Asymmetry; Pedigree; Forkhead Transcription Factors
PubMed: 37041148
DOI: 10.1038/s41467-023-37703-6 -
Developmental Dynamics : An Official... Sep 2020The spliceosome is a complex of RNA and proteins that function together to identify intron-exon junctions in precursor messenger-RNAs, splice out the introns, and join... (Review)
Review
The spliceosome is a complex of RNA and proteins that function together to identify intron-exon junctions in precursor messenger-RNAs, splice out the introns, and join the flanking exons. Mutations in any one of the genes encoding the proteins that make up the spliceosome may result in diseases known as spliceosomopathies. While the spliceosome is active in all cell types, with the majority of the proteins presumably expressed ubiquitously, spliceosomopathies tend to be tissue-specific as a result of germ line or somatic mutations, with phenotypes affecting primarily the retina in retinitis pigmentosa, hematopoietic lineages in myelodysplastic syndromes, or the craniofacial skeleton in mandibulofacial dysostosis. Here we describe the major spliceosomopathies, review the proposed mechanisms underlying retinitis pigmentosa and myelodysplastic syndromes, and discuss how this knowledge may inform our understanding of craniofacial spliceosomopathies.
Topics: Animals; Humans; Mandibulofacial Dysostosis; Mutation; Myelodysplastic Syndromes; Retinitis Pigmentosa; Spliceosomes
PubMed: 32506634
DOI: 10.1002/dvdy.214 -
American Journal of Ophthalmology Dec 2021
Topics: Goldenhar Syndrome; Humans; Tomography, X-Ray Computed
PubMed: 34551320
DOI: 10.1016/j.ajo.2021.09.012 -
BMJ Case Reports Jun 2024Goldenhar syndrome, also recognised as oculo-auriculo-vertebral spectrum, is a very rare condition distinguished by a diverse array of clinical abnormalities affecting...
Goldenhar syndrome, also recognised as oculo-auriculo-vertebral spectrum, is a very rare condition distinguished by a diverse array of clinical abnormalities affecting the ocular, auditory, vertebral and various organ systems. The pathophysiology of this condition is not fully elucidated due to its inherent genetic variability and rarity. In this report, we present a case of Goldenhar syndrome in a toddler boy, aiming to enhance the existing body of literature on this condition.
Topics: Humans; Goldenhar Syndrome; Male; Child, Preschool
PubMed: 38839403
DOI: 10.1136/bcr-2024-259872 -
American Journal of Medical Genetics.... Dec 2020The aim of this study was to perform 22q11.2 deletion screening and chromosomal microarray analysis (CMA) in individuals clinically diagnosed with craniofacial... (Review)
Review
The aim of this study was to perform 22q11.2 deletion screening and chromosomal microarray analysis (CMA) in individuals clinically diagnosed with craniofacial microsomia (CFM) and review previously published cases of CFM with genomic imbalances. It included 54 individuals who were evaluated by a clinical geneticist. Copy number variants (CNVs) in the 22q11.2 region were investigated by multiplex ligation-dependent probe amplification (MLPA) for all individuals. The CMA was performed only for individuals with additional major features. MLPA revealed pathogenic CNVs at the 22q11 region in 3/54 (5.6%) individuals. CMA revealed pathogenic CNVs in 4/17 (23.5%) individuals, including the three CNVs at the 22q11 region also detected by MLPA, and CNVs classified as variants of unknown significance (VOUS) in 4/17 (23.5%) individuals. Pathogenic alterations were found at the 2p12, 5p15, 13q13, and 22q11 regions. VOUS were found at 3q29, 5q22.2, 5q22.1, and 9p22 regions. All individuals with pathogenic alterations presented additional major features, including congenital heart disease (CHD). The literature review revealed pathogenic CNVs in 17/193 (8.8%) individuals and most of them also presented additional major features, such as CHD, renal anomalies, or developmental delay. In conclusion, CNVs should be investigated in patients with CFM and additional major features.
Topics: DNA Copy Number Variations; Genomics; Goldenhar Syndrome; Heart Defects, Congenital; Humans; Microarray Analysis
PubMed: 33215817
DOI: 10.1002/ajmg.c.31857