Ttc30a affects tubulin modifications in a model for ciliary chondrodysplasia with polycystic kidney disease

Skeletal ciliopathies (e.g., Jeune syndrome, short rib polydactyly syndrome, and Sensenbrenner syndrome) are frequently associated with nephronophthisis-like cystic kidney disease and other organ manifestations. Despite recent progress in genetic mapping of causative loci, a common molecular mechanism of cartilage defects and cystic kidneys has remained elusive. Targeting two ciliary chondrodysplasia loci (ift80 and ift172) by CRISPR/Cas9 mutagenesis, we established models for skeletal ciliopathies in Xenopus tropicalis. Froglets exhibited severe limb deformities, polydactyly, and cystic kidneys, closely matching the phenotype of affected patients. A data mining–based in silico screen found ttc30a to be related to known skeletal ciliopathy genes. CRISPR/Cas9 targeting replicated limb malformations and renal cysts identical to the models of established disease genes. Loss of Ttc30a impaired embryonic renal excretion and ciliogenesis because of altered posttranslational tubulin acetylation, glycylation, and defective axoneme compartmentalization. Ttc30a/b transcripts are enriched in chondrocytes and osteocytes of single-cell RNA-sequenced embryonic mouse limbs. We identify TTC30A/B as an essential node in the network of ciliary chondrodysplasia and nephronophthisis-like disease proteins and suggest that tubulin modifications and cilia segmentation contribute to skeletal and renal ciliopathy manifestations of ciliopathies in a cell type–specific manner. These findings have implications for potential therapeutic strategies.

A new technique for neonatal Jeune syndrome: External thoracic expansion

Jeune syndrome is a rare form of skeletal dysplasia characterized by a narrow, bell-shaped chest (thoracic cage), and typical phalangeal and pelvic bone deformities. Chest expansion is impaired by the short, horizontally positioned ribs, resulting in alveolar hypoventilation and eventually neonatal-infantile death in most cases. External distraction with sternoplasty is a new technique for the treatment of Jeune syndrome, which was firstly used by our team on a newborn by placing a sliding finger fixator which was designed for ulnar lengthening. We believe that this approach can be life-saving in neonates with improved and widespread usage.

Surgical treatment of Jeune syndrome in a child (rare clinical case and review)

Objective: possibility of surgical treatment of chest deformity in children with Jeune syndrome (analysis of the clinical case), review of literature on Jeune syndrome in children. Methods: clinical, radiological, laboratory, instrumental, statistical. Results: Positive outcome of surgical treatment of a 3-year-old patient with severe chest deformity and severe respiratory failure. Conclusions: Jeune syndrome is a severe disease with a high mortality rate. A multidisciplinary approach is required in the treatment of patients with this pathology. Surgical intervention aimed at reducing the compression of the chest organs and increasing its volume, even in conditions of decompensation, allows you to stop the phenomenon of respiratory failure.

THE CASE OF JEUNE SYNDROME AMONG THE PRECARPATHIAN POPULATION

Despite the fact that Jeune syndrome is rather rare, neonatologists and pediatricians need to be aware of this pathology. This will facilitate early diagnostics of the condition and aid in the choice of the most adequate algorithms for its monitoring and treatment. The aim: To describe the case of Jeune syndrome among the Precarpathian population. Infant patient with Jeune syndrome and relevant medical records. Methods used in the study: clinical-genealogical and syndromal analysis, general clinical examination, radiologic method, including computed tomography (CТ) scan with 3D image reconstruction, methods of ultrasound diagnostics. The study was conducted in accordance with the Declaration of Helsinki Ethical Principles. The newborn baby was diagnosed with asphyxiating thoracic dystrophy on the basis of personal observation and conducted complex examination. According to the literature, this syndrome is rarely diagnosed in this age group. The diagnosis was based on the clinical and phenotypic manifestations of the syndrome, primarily on the characteristic association of symptoms of specific chest deformity and severe respiratory failure with oxygen dependence in the patient. Skeletal and pulmonary changes on radiographs and computed tomography scans were rather indicative. Brief follow-up data on the patient at the age of nine months are given.

Expression patterns of ciliopathy genes ARL3 and CEP120 reveal roles in multisystem development

Background Joubert syndrome and related disorders (JSRD) and Jeune syndrome are multisystem ciliopathy disorders with overlapping phenotypes. There are a growing number of genetic causes for these rare syndromes, including the recently described genes ARL3 and CEP120. Methods We sought to explore the developmental expression patterns of ARL3 and CEP120 in humans to gain additional understanding of these genetic conditions. We used an RNA in situ detection technique called RNAscope to characterise ARL3 and CEP120 expression patterns in human embryos and foetuses in collaboration with the MRC-Wellcome Trust Human Developmental Biology Resource. Results Both ARL3 and CEP120 are expressed in early human brain development, including the cerebellum and in the developing retina and kidney, consistent with the clinical phenotypes seen with pathogenic variants in these genes. Conclusions This study provides insights into the potential pathogenesis of JSRD by uncovering the spatial expression of two JSRD-causative genes during normal human development.

CRISPR/Cas9 targeting Ttc30a mimics ciliary chondrodysplasia with polycystic kidney disease

Skeletal ciliopathies (e.g. Jeune syndrome, short rib polydactyly syndrome, Sensenbrenner syndrome) are frequently associated with cystic kidney disease and other organ manifestations, but a common molecular mechanism has remained elusive.We established two models for skeletal ciliopathies (ift80 and ift172) in Xenopus tropicalis, which exhibited severe limb deformities, polydactyly, cystic kidneys, and ciliogenesis defects, closely matching the phenotype of affected patients.Employing data-mining and an in silico screen we identified candidate genes with similar molecular properties to genetically validated skeletal ciliopathy genes. Among four genes experimentally validated, CRISPR/Cas9 targeting of ttc30a replicated all aspects of the phenotypes observed in the models of genetically confirmed disease genes, including ciliary defects, limb deformations and cystic kidney disease.Our findings establish three new models for skeletal ciliopathies (ift80, ift172, ttc30a) and identify TTC30A/B as an essential node in the network of ciliary chondrodysplasia and nephronophthisis-like disease proteins implicating post-translational tubulin modifications in its pathogenesis.