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Abstract Background Bardet-Biedl syndrome (BBS) is a type of non-motile ciliopathy. To date, 26 genes have been reported to be associated with BBS. However, BBS is genetically heterogeneous, with significant clinical overlap with other ciliopathies, which complicates diagnosis. Disability and mortality rates are high in BBS patients; therefore, it is urgent to improve our understanding of BBS. Thus, our study aimed to describe the genotypic and phenotypic spectra of BBS in China and to elucidate genotype–phenotype correlations. Methods Twenty Chinese patients diagnosed with BBS were enrolled in this study. We compared the phenotypes of Chinese BBS patients in this study with those from other countries to analyze the phenotypic differences across patients worldwide. In addition, genotype–phenotype correlations were described for our cohort. We also summarized all previously reported cases of BBS in Chinese patients (71 patients) and identified common and specific genetic variants in the Chinese population. Results Twenty-eight variants, of which 10 are novel, in 5 different BBS-associated genes were identified in 20 Chinese BBS patients. By comparing the phenotypes of BBSome-coding genes (BBS2,7,9) with those of chaperonin-coding genes (BBS10,12), we found that patients with mutations in BBS10 and 12 had an earlier age of onset (1.10 Vs. 2.20, p T (10/182 alleles) and BBS7: c.1002delT (7/182 alleles), marking a difference from the genotypic spectra of BBS reported abroad. Conclusions We recruited 20 Chinese patients with BBS for genetic and phenotypic analyses, and identified common clinical manifestations, pathogenic genes, and variants. We also described the phenotypic differences across patients worldwide and among different BBS-associated genes. This study involved the largest cohort of Chinese patients with BBS, and provides new insights into the distinctive clinical features of specific pathogenic variants.

Background: Bardet-Biedl syndrome (BBS) is a rare, systemic, hereditary disorder characterised by obesity, polydactyly, visual and auditory impairment, and cognitive disability. Providing quality education in appropriate schools for children who present with such complex chronic conditions is challenging. Objectives: This study explored the dimensions of psycho-educational support needs for a child with BBS in South Africa to contribute to the improvement of early detection and holistic interventions. Method: A descriptive in-depth qualitative case study of Gezani, an adolescent Tsonga boy diagnosed with BBS, was undertaken. Semi-structured interviews were conducted with his parents and teachers to ascertain the boy’s psycho-educational support needs. Medical reports provided information on the complexities and prognosis of the syndrome. Observations in the classroom corroborated the learner’s symptoms and behaviours. Results: Thematic content analysis revealed the key areas of support needs. Gezani’s cognitive disability required a modified, slow-paced curriculum. His visual impairment required mobility orientation training and learning Braille. His emotional needs were supported with psychotherapy to maintain a sense of well-being. Medical monitoring was recommended with interventions for walking and managing his diet and weight. Speech therapy supported his communication skills. Conclusion: Learners with multiple disabilities require carefully planned, individualised psycho-educational support programmes addressing their unique needs and delays with targeted remedial interventions in appropriate special needs schools. Contribution: This study informs educators about BBS and provides multi-faceted, holistic support. The Department of Basic Education could bring special schools and national policies in tighter alignment for learners presenting with complex disabilities.

Obesity is a metabolic state generated by the expansion of adipose tissue. Adipose tissue expansion depends on the interplay between hyperplasia and hypertrophy, and is mainly regulated by a complex interaction between genetics and excess energy intake. However, the genetic regulation of adipose tissue expansion is yet to be fully understood. Obesity can be divided into common multifactorial/polygenic obesity and monogenic obesity, non-syndromic and syndromic. Several genes related to obesity were found through studies of monogenic non-syndromic obesity models. However, syndromic obesity, characterized by additional features other than obesity, suggesting a more global role of the mutant genes related to the syndrome and, thus, an additional peripheral influence on the development of obesity, were hardly studied to date in this regard. This review summarizes present knowledge regarding the hyperplasia and hypertrophy of adipocytes in common obesity. Additionally, we highlight the scarce research on syndromic obesity as a model for studying adipocyte hyperplasia and hypertrophy, focusing on Bardet–Biedl syndrome (BBS). BBS obesity involves central and peripheral mechanisms, with molecular and mechanistic alternation in adipocyte hyperplasia and hypertrophy. Thus, we argue that using syndromic obesity models, such as BBS, can further advance our knowledge regarding peripheral adipocyte regulation in obesity. [ABSTRACT FROM AUTHOR]

Background: Bardet-Biedl syndrome (BBS) is a rare, systemic, hereditary disorder characterised by obesity, polydactyly, visual and auditory impairment, and cognitive disability. Providing quality education in appropriate schools for children who present with such complex chronic conditions is challenging. Objectives: This study explored the dimensions of psycho-educational support needs for a child with BBS in South Africa to contribute to the improvement of early detection and holistic interventions. Method: A descriptive in-depth qualitative case study of Gezani, an adolescent Tsonga boy diagnosed with BBS, was undertaken. Semi-structured interviews were conducted with his parents and teachers to ascertain the boy's psycho-educational support needs. Medical reports provided information on the complexities and prognosis of the syndrome. Observations in the classroom corroborated the learner's symptoms and behaviours. Results: Thematic content analysis revealed the key areas of support needs. Gezani's cognitive disability required a modified, slow-paced curriculum. His visual impairment required mobility orientation training and learning Braille. His emotional needs were supported with psychotherapy to maintain a sense of well-being. Medical monitoring was recommended with interventions for walking and managing his diet and weight. Speech therapy supported his communication skills. Conclusion: Learners with multiple disabilities require carefully planned, individualised psycho-educational support programmes addressing their unique needs and delays with targeted remedial interventions in appropriate special needs schools. Contribution: This study informs educators about BBS and provides multi-faceted, holistic support. The Department of Basic Education could bring special schools and national policies in tighter alignment for learners presenting with complex disabilities. [ABSTRACT FROM AUTHOR]

Obesity is a metabolic state generated by the expansion of adipose tissue. Adipose tissue expansion depends on the interplay between hyperplasia and hypertrophy, and is mainly regulated by a complex interaction between genetics and excess energy intake. However, the genetic regulation of adipose tissue expansion is yet to be fully understood. Obesity can be divided into common multifactorial/polygenic obesity and monogenic obesity, non-syndromic and syndromic. Several genes related to obesity were found through studies of monogenic non-syndromic obesity models. However, syndromic obesity, characterized by additional features other than obesity, suggesting a more global role of the mutant genes related to the syndrome and, thus, an additional peripheral influence on the development of obesity, were hardly studied to date in this regard. This review summarizes present knowledge regarding the hyperplasia and hypertrophy of adipocytes in common obesity. Additionally, we highlight the scarce research on syndromic obesity as a model for studying adipocyte hyperplasia and hypertrophy, focusing on Bardet–Biedl syndrome (BBS). BBS obesity involves central and peripheral mechanisms, with molecular and mechanistic alternation in adipocyte hyperplasia and hypertrophy. Thus, we argue that using syndromic obesity models, such as BBS, can further advance our knowledge regarding peripheral adipocyte regulation in obesity.

Mutations in serologically defined colon cancer autoantigen protein 8 (SDCCAG8) were first identified in retinal ciliopathy families a decade ago with unknown function. To investigate the pathogenesis of SDCCAG8-associated retinal ciliopathies in vivo, we employed CRISPR/Cas9- mediated homology-directed recombination (HDR) to generate two knock-in mouse models, Sdccag8Y236X/Y236X and Sdccag8E451GfsX467/E451GfsX467, which carry truncating mutations of the mouse Sdccag8, corresponding to mutations that cause Bardet-Biedl syndrome (BBS) and Senior-Løken syndrome (SLS) (c.696T>G p.Y232X and c.1339–1340insG p.E447GfsX463) in humans, respectively. The two mutant Sdccag8 knock-in mice faithfully recapitulated human SDCCAG8-associated BBS phenotypes such as rod-cone dystrophy, cystic renal disorder, polydactyly, infertility, and growth retardation, with varied age of onset and severity depending on the hypomorphic strength of the Sdccag8 mutations. To the best of our knowledge, these knock-in mouse lines are the first BBS mouse models to present with the polydactyly phenotype. Major phototransduction protein mislocalization was also observed outside the outer segment after initiation of photoreceptor degeneration. Impaired cilia were observed in the mutant photoreceptors, renal epithelial cells, and mouse embryonic fibroblasts derived from the knock-in mouse embryos, suggesting that SDCCAG8 plays an essential role in ciliogenesis, and cilium defects are a primary driving force of SDCCAG8-associated retinal ciliopathies. [ABSTRACT FROM AUTHOR]

Subglottic stenosis is characterized by the narrowing of the airway at the inferior edge of the cricoid cartilage level. It is either congenital or acquired, the latter being more commonly secondary to internal iatrogenic trauma. Airway management of these cases is challenging and requires multidisciplinary discussion. We present a case of a 17-year-old boy scheduled for tracheostomy in the context of subglottic stenosis probably caused by prolonged endotracheal intubation. On the day of surgery, it was decided to perform an asleep fiberoptic visualization of the lesion through a supraglottic device, which revealed a narrow circumferential fibrous membrane just below the vocal cords. Given the findings, a suspension laryngoscopy accompanied by supraglottic manual jet ventilation was performed. Balloon dilatation with the application of mitomycin C was the elected otorhinolaryngologic technique. At the end of the procedure, a fiberoptic exam was performed and only a minimal portion of the membrane remained. The patient was asymptomatic on follow-up visits. We aim to raise awareness of how the anesthetic management of patients with subglottic stenosis may prove challenging. Communication between anesthetic and surgical teams is essential for the achievement of the main goal, which is the acquisition of an adequate airway that allows normal patient activity associated with minimal postoperative morbidity., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Pereira et al.)

Purpose: Bardet–Biedl syndrome (BBS: OMIM 209,900) is a rare ciliopathic human genetic disorder that affects many parts of the body systems. BBS is a genetically heterogeneous disorder with a wide spectrum of clinical manifestations which makes its diagnosis and management more challenging. RetNet reports 18 genes that cause BBS and each of genes has had several known mutations. Genetic studies suggesting that serologically defined colon cancer antigen 8 (SDCCAG8) gene mutations are a major cause of BBS. Materials and methods: In this section, we investigated the consanguineous Iranian family members with BBS. Whole-exome sequencing and Sanger sequencing, were performed to screen and confirm the suspicious pathogenic mutations. The identified mutation was investigated using bioinformatics tools to predict the effect of the mutation on protein structure. Results: Sequential analysis identified a novel splice site mutation c.1221 + 2 T > A in the SDCCAG8 gene in BBS patients. Structure-based approaches have predicted significant structural alterations in SDCCAG8 protein. Conclusions: This study was conducted to show the aberrant alternative splicing as one of the single splicing mutations identified can cause BBS by affecting the function of SDCCAG8 protein. [ABSTRACT FROM AUTHOR]

Bardet-Biedl syndrome (BBS) is an inherited disorder primarily ciliopathy with pleiotropic multi-systemic phenotypic involvement, including adipose, nerve, retinal, kidney, Etc. Consequently, it is characterized by obesity, cognitive impairment and retinal, kidney and cutaneous abnormalities. Initial studies, including ours have shown that BBS genes play a role in the early developmental stages of adipocytes and β-cells. However, this role in other BBS-related tissues is unknown. We investigated BBS genes involvement in the proliferation and early differentiation of different BBS cell types. The involvement of BBS genes in cellular proliferation were studied in seven in-vitro and transgenic cell models; keratinocytes (hHaCaT) and Ras-transfected keratinocytes (Ras-hHaCaT), neuronal cell lines (hSH-SY5Y and rPC-12), silenced BBS4 neural cell lines (siBbs4 hSH-SY5Y and siBbs4 rPC-12), adipocytes (m3T3L1), and ex-vivo transformed B-cells obtain from BBS4 patients, using molecular and biochemical methodologies. RashHaCaT cells showed an accelerated proliferation rate in parallel to significant reduction in the transcript levels of BBS1, 2, and 4. BBS1, 2, and 4 transcripts linked with hHaCaT cell cycle arrest (G1 phase) using both chemical (CDK4 inhibitor) and serum deprivation methodologies. Adipocyte (m3T3-L1) Bbs1, 2 and 4 transcript levels corresponded to the cell cycle phase (CDK4 inhibitor and serum deprivation). SiBBS4 hSH-SY5Y cells exhibited early cell proliferation and differentiation (wound healing assay) rates. SiBbs4 rPC-12 models exhibited significant proliferation and differentiation rate corresponding to Nestin expression levels. BBS4 patients-transformed B-cells exhibited an accelerated proliferation rate (LPS-induced methodology). In conclusions, the BBS4 gene plays a significant, similar and global role in the cellular proliferation of various BBS related tissues. These results highlight the universal role of the BBS gene in the cell cycle, and further deepen the knowledge of the mechanisms underlying the development of BBS., (Copyright © 2024. Published by Elsevier B.V.)

Background: Bardet-Biedl syndrome (BBS) is a rare, systemic, hereditary disorder characterised by obesity, polydactyly, visual and auditory impairment, and cognitive disability. Providing quality education in appropriate schools for children who present with such complex chronic conditions is challenging., Objectives: This study explored the dimensions of psycho-educational support needs for a child with BBS in South Africa to contribute to the improvement of early detection and holistic interventions., Method: A descriptive in-depth qualitative case study of Gezani, an adolescent Tsonga boy diagnosed with BBS, was undertaken. Semi-structured interviews were conducted with his parents and teachers to ascertain the boy's psycho-educational support needs. Medical reports provided information on the complexities and prognosis of the syndrome. Observations in the classroom corroborated the learner's symptoms and behaviours., Results: Thematic content analysis revealed the key areas of support needs. Gezani's cognitive disability required a modified, slow-paced curriculum. His visual impairment required mobility orientation training and learning Braille. His emotional needs were supported with psychotherapy to maintain a sense of well-being. Medical monitoring was recommended with interventions for walking and managing his diet and weight. Speech therapy supported his communication skills., Conclusion: Learners with multiple disabilities require carefully planned, individualised psycho-educational support programmes addressing their unique needs and delays with targeted remedial interventions in appropriate special needs schools., Contribution: This study informs educators about BBS and provides multi-faceted, holistic support. The Department of Basic Education could bring special schools and national policies in tighter alignment for learners presenting with complex disabilities., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2023. The Authors.)

Bardet-Biedl syndrome (BBS) is a pleiotropic and clinically and genetically heterogeneous ciliopathy. Primary features are early-onset retinal dystrophy that is typically rod-cone, obesity, polydactyly, renal abnormalities, hypogonadism, and learning difficulties, but most patients do not present with the full clinical picture. In a BBS patient from a consanguineous marriage we performed next-generation sequencing targeting all known BBS genes and other genes known or hypothesized to cause ciliopathies. While no mutation was present in any of the recognized genes for BBS, we were able to identify the homozygous non-conservative mutation c.529C>T (p.Arg177Trp) in C8orf37 that segregated with the phenotype, affects an evolutionarily highly conserved residue, and is bioinformatically predicted to be pathogenic. The same mutation has been described in unrelated patients with non-syndromic cone-rod dystrophy and other C8orf37 changes were found in individuals with retinitis pigmentosa. We conclude that C8orf37 should be added to BBS screening panels as a probable rare cause of the disease and that individuals with C8orf37-related retinal dystrophy should be screened for BBS features. [ABSTRACT FROM AUTHOR]

The primary cilium, a microtubule-based organelle found in most cells, is a centre for mechano-sensing fluid movement and cellular signalling, notably through the Hedgehog pathway. We recently found that each lens fibre cell has an apically situated primary cilium that is polarised to the side of the cell facing the anterior pole of the lens. The direction of polarity is similar in neighbouring cells so that in the global view, lens fibres exhibit planar cell polarity (PCP) along the equatorial-anterior polar axis. Ciliogenesis has been associated with the establishment of PCP, although the exact relationship between PCP and the role of cilia is still controversial. To test the hypothesis that the primary cilia have a role in coordinating the precise alignment/orientation of the fibre cells, IFT88, a key component of the intraflagellar transport (IFT) complex, was removed specifically from the lens at different developmental stages using several lens-specific Cre-expressing mouse lines (MLR10- and LR-Cre). Irrespective of which Cre-line was adopted, both demonstrated that in IFT88-depleted cells, the ciliary axoneme was absent or substantially shortened, confirming the disruption of primary cilia formation. However no obvious histological defects were detected even when IFT88 was removed from the lens placode as early as E9.5. Specifically, the lens fibres aligned/oriented towards the poles to form the characteristic Y-shaped sutures as normal. Consistent with this, in primary lens epithelial explants prepared from these conditional knockout mouse lenses, the basal bodies still showed polarised localisation at the apical surface of elongating cells upon FGF-induced fibre differentiation. We further investigated the lens phenotype in knockouts of Bardet–Biedl Syndrome (BBS) proteins 4 and 8, the components of the BBSome complex which modulate ciliary function. In these BBS4 and 8 knockout lenses, again we found the pattern of the anterior sutures formed by the apical tips of elongating/migrating fibres were comparable to the control lenses. Taken together, these results indicate that primary cilia do not play an essential role in the precise cellular alignment/orientation of fibre cells. Thus, it appears that in the lens cilia are not required to establish PCP. [ABSTRACT FROM AUTHOR]

From July 19–24, 2015, 169 clinicians and basic scientists gathered in the vertiginous heights of Snowmass, Colorado (2502 m) for the fourth FASEB summer research conference on the ‘Biology of Cilia and Flagella’. Organizers Maureen Barr (Rutgers University), Iain Drummond (Massachusetts General Hospital/Harvard Medical School), and Jagesh Shah (Brigham and Women's Hospital/Harvard Medical School) assembled a program filled with new data and forward-thinking ideas documenting the ongoing growth of the field. Sixty oral presentations and 77 posters covered novel aspects of cilia structure, ciliogenesis, cilia motility, cilia-mediated signaling, and cilia-related disease. In this report, we summarize the meeting, highlight exciting developments and discuss open questions. [ABSTRACT FROM AUTHOR]

BBS4 is one of several proteins whose defects cause Bardet-Biedl syndrome (BBS), a multi-systemic disorder, manifesting with marked obesity. BBS4 polymorphisms have been associated with common non-syndromic morbid obesity. BBS4 obesity molecular mechanisms, and the role of the BBS4 gene in adipocyte differentiation and function are not entirely known. We now show that Bbs4 plays a direct and essential role in proliferation and adipogenesis: silencing of Bbs4 in 3T3F442A preadipocytes induced accelerated cell division and aberrant differentiation, evident through morphologic studies (light, scanning and transmission electron microscopy), metabolic analyses (fat accumulation, fatty acid profile and lipolysis) and adipogenic markers transcripts ( Cebpα, Pparγ, aP2, ADRP, Perilipin). Throughout adipogenesis and when challenged with fat load, Bbs4 silenced cells accumulate significantly more triglycerides than control adipocytes, albeit in smaller (yet greater in number) droplets containing modified fatty acid profiles. Thus, greater fat accumulation in the silenced cells is a consequence of both a higher rate of adipocyte proliferation and of aberrant differentiation leading to augmented aberrant accumulation of fat per cell. Our findings suggest that the BBS obesity might be partly due to a direct role of BBS4 in physiological and pathophysiological mechanisms that underlie adipose tissue formation relevant to obesity. [ABSTRACT FROM AUTHOR]

Bardet-Biedl syndrome (BBS) is a rare heterogeneous autosomal recessive disorder characterized by rod-cone dystrophy, postaxial polydactyly, truncal obesity, hypogonadism, learning disability, and renal anomaly that are caused by ciliary dysfunction. 16 genes have been associated with the BBS phenotype. Although recent pathophysiological studies using animal models have shown that ciliary dysfunction may induce hydrocephalus, there have been no reports of BBS with intracranial hypertension. We here describe a 9-year-old Japanese girl who was diagnosed as having BBS and later received renal transplantation due to chronic renal failure. She also exhibited intracranial hypertension, including papilledema and increased intrathecal pressure (260-300 mmH2O), but her brain magnetic resonance imaging was normal. No genetic abnormalities were detected by DNA chip analysis or exome sequencing. Her papilledema improved following administration of acetazolamide. This is the first report of a case of BBS complicated with intracranial hypertension and its treatment. [ABSTRACT FROM AUTHOR]

Abstract: Rhodopsin is a key molecular constituent of photoreceptor cells, yet understanding of how it regulates photoreceptor membrane trafficking and biogenesis of light-sensing organelles, the rod outer segments (ROS) is only beginning to emerge. Recently identified sequence of well-orchestrated molecular interactions of rhodopsin with the functional networks of Arf and Rab GTPases at multiple stages of intracellular targeting fits well into the complex framework of the biogenesis and maintenance of primary cilia, of which the ROS is one example. This review will discuss the latest progress in dissecting the molecular complexes that coordinate rhodopsin incorporation into ciliary-targeted carriers with the recruitment and activation of membrane tethering complexes and regulators of fusion with the periciliary plasma membrane. In addition to revealing the fundamental principals of ciliary membrane renewal, recent advances also provide molecular insight into the ways by which disruptions of the exquisitely orchestrated interactions lead to cilia dysfunction and result in human retinal dystrophies and syndromic diseases that affect multiple organs, including the eyes. [Copyright &y& Elsevier]

Highlights: [•] TUDCA prevented cell death induced by high glucose concentration. [•] TUDCA prevented AIF translocation induced by high glucose concentration. [•] TUDCA prevented oxidative stress induced by elevated glucose concentration. [ABSTRACT FROM AUTHOR]

Cilia are antenna-like organelles found on the surface of most cells. They transduce molecular signals and facilitate interactions between cells and their environment. Ciliary dysfunction has been shown to underlie a broad range of overlapping, clinically and genetically heterogeneous phenotypes, collectively termed ciliopathies. Literally, all organs can be affected. Frequent cilia-related manifestations are (poly)cystic kidney disease, retinal degeneration, situs inversus, cardiac defects, polydactyly, other skeletal abnormalities, and defects of the central and peripheral nervous system, occurring either isolated or as part of syndromes. Characterization of ciliopathies and the decisive role of primary cilia in signal transduction and cell division provides novel insights into tumorigenesis, mental retardation, and other common causes of morbidity and mortality, including diabetes mellitus and obesity. New technologies ('Next generation sequencing/NGS') have considerably improved genetic research and diagnostics by allowing simultaneous investigation of all disease genes at reduced costs and lower turn-around times. This is undoubtedly a result of the dynamic development in the field of human genetics and deserves increased attention in genetic counselling and the management of affected families. [ABSTRACT FROM AUTHOR]

Mutations in serologically defined colon cancer autoantigen protein 8 ( SDCCAG8 ) were first identified in retinal ciliopathy families a decade ago with unknown function. To investigate the pathogenesis of SDCCAG8-associated retinal ciliopathies in vivo , we employed CRISPR/Cas9-mediated homology-directed recombination (HDR) to generate two knock-in mouse models, Sdccag8 Y236X/Y236X and Sdccag8 , corresponding to mutations that cause Bardet-Biedl syndrome (BBS) and Senior-Løken syndrome (SLS) (c.696T>G p.Y232X and c.1339-1340insG p.E447GfsX463) in humans, respectively. The two mutant E451GfsX467/E451GfsX467 , which carry truncating mutations of the mouse Sdccag8 , corresponding to mutations that cause Bardet-Biedl syndrome (BBS) and Senior-Løken syndrome (SLS) (c.696T>G p.Y232X and c.1339-1340insG p.E447GfsX463) in humans, respectively. The two mutant Sdccag8 knock-in mice faithfully recapitulated human SDCCAG8-associated BBS phenotypes such as rod-cone dystrophy, cystic renal disorder, polydactyly, infertility, and growth retardation, with varied age of onset and severity depending on the hypomorphic strength of the Sdccag8 mutations. To the best of our knowledge, these knock-in mouse lines are the first BBS mouse models to present with the polydactyly phenotype. Major phototransduction protein mislocalization was also observed outside the outer segment after initiation of photoreceptor degeneration. Impaired cilia were observed in the mutant photoreceptors, renal epithelial cells, and mouse embryonic fibroblasts derived from the knock-in mouse embryos, suggesting that SDCCAG8 plays an essential role in ciliogenesis, and cilium defects are a primary driving force of SDCCAG8-associated retinal ciliopathies.

Renal cystic disease encompasses a large variety of illnesses with various phenotypic expressions that can manifest in utero, in infancy, and in childhood. These diseases may be unilateral or bilateral and present with single or multiple cysts. Various cystic diseases may also progress to chronic kidney disease (CKD), including kidney failure, and hepatic disease, thus potentially being life threatening. The prevalence and serious complications of CKD in the pediatric population make it vital that health care providers detect these conditions early and provide effective management. This installment of AJKD's Core Curriculum in Nephrology discusses various genetic and sporadic kidney cystic diseases, including multicystic dysplastic kidney, nephronophthisis, cystic dysplasia, hepatocyte nuclear factor 1-β (HNF1-β) nephropathy, Bardet-Biedl syndrome, Meckel-Gruber syndrome, Zellweger syndrome, calyceal diverticulum, autosomal recessive polycystic kidney disease (ARPKD), and autosomal dominant polycystic kidney disease (ADPKD). This article discusses the epidemiology, genetics and pathophysiology, diagnosis, presentation, and management for each of these renal cystic diseases, with particular attention to prenatal care and pregnancy counseling., (Copyright © 2021 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Primary cilia are specialized sensory organelles that protrude from the apical surface of most cell types. During the past 2 decades, they have been found to play important roles in tissue development and signal transduction, with mutations in ciliary-associated proteins resulting in a group of diseases collectively known as ciliopathies. Many of these mutations manifest as renal ciliopathies, characterized by kidney dysfunction resulting from aberrant cilia or ciliary functions. This group of overlapping and genetically heterogeneous diseases includes polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome as the main focus of this review. Renal ciliopathies are characterized by the presence of kidney cysts that develop due to uncontrolled epithelial cell proliferation, growth, and polarity, downstream of dysregulated ciliary-dependent signaling. Due to cystic-associated kidney injury and systemic inflammation, cases result in kidney failure requiring dialysis and transplantation. Of the handful of pharmacologic treatments available, none are curative. It is important to determine the molecular mechanisms that underlie the involvement of the primary cilium in cyst initiation, expansion, and progression for the development of novel and efficacious treatments. This review updates research progress in defining key genes and molecules central to ciliogenesis and renal ciliopathies., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

In golden retriever dogs, a 1 bp deletion in the canine TTC8 gene has been shown to cause progressive retinal atrophy (PRA), the canine equivalent of retinitis pigmentosa. In humans, TTC8 is also implicated in Bardet-Biedl syndrome (BBS). To investigate if the affected dogs only exhibit a non-syndromic PRA or develop a syndromic ciliopathy similar to human BBS, we recruited 10 affected dogs to the study. The progression of PRA for two of the dogs was followed for 2 years, and a rigorous clinical characterization allowed a careful comparison with primary and secondary characteristics of human BBS. In addition to PRA, the dogs showed a spectrum of clinical and morphological signs similar to primary and secondary characteristics of human BBS patients, such as obesity, renal anomalies, sperm defects, and anosmia. We used Oxford Nanopore long-read cDNA sequencing to characterize retinal full-length TTC8 transcripts in affected and non-affected dogs, the results of which suggest that three isoforms are transcribed in the retina, and the 1 bp deletion is a loss-of-function mutation, resulting in a canine form of Bardet-Biedl syndrome with heterogeneous clinical signs.

Bardet-Biedl syndrome (BBS) is a rare heterogeneous autosomal recessive disorder characterized by rod-cone dystrophy, postaxial polydactyly, truncal obesity, hypogonadism, learning disability, and renal anomaly that are caused by ciliary dysfunction. 16 genes have been associated with the BBS phenotype. Although recent pathophysiological studies using animal models have shown that ciliary dysfunction may induce hydrocephalus, there have been no reports of BBS with intracranial hypertension. We here describe a 9-year-old Japanese girl who was diagnosed as having BBS and later received renal transplantation due to chronic renal failure. She also exhibited intracranial hypertension, including papilledema and increased intrathecal pressure (260-300 mmH2O), but her brain magnetic resonance imaging was normal. No genetic abnormalities were detected by DNA chip analysis or exome sequencing. Her papilledema improved following administration of acetazolamide. This is the first report of a case of BBS complicated with intracranial hypertension and its treatment., (Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)