Clinical insights gained from eight new cases and review of reported cases with Jeune syndrome (asphyxiating thoracic dystrophy)

Lateral Thoracic Expansion for Jeune's Syndrome, Surgical Approach, and Technical Details

INTRODUCTION

 Jeune's syndrome, or asphyxiating thoracic dystrophy (ATD), is a rare autosomal recessive disorder characterized by skeletal dysplasia. Ribs are typically short and horizontal resulting-in lethal variant-in severe lung hypoplasia, progressive respiratory failure, and death. Lateral thoracic expansion (LTE) consists in staggered bilateral ribs osteotomy leading to chest expansion and lung development. Studies on LTE in ATD patients report encouraging data, but the rarity of ATD implies the lack of a standardized surgical path. The aim of this report is to present our experience with LTE, the technical modification we adopted, and patients' clinical outcome.

MATERIALS AND METHODS

 We retrospectively reviewed data of 11 LTE performed in 7 ATD patients with lethal variant. Information regarding pre- and postoperative clinical conditions and surgical details was collected. We adopted a single-stage or a two-stage approach based on patient clinical condition. Computed tomography (CT) scan was performed before and after surgery and lung volume was calculated.

RESULTS

 Five patients are alive, while two died in intensive care unit for other than respiratory cause (sepsis). Most patients experienced clinical improvement in terms of decreased respiratory infections rate, need for ventilation, and improved exercise tolerance. Postoperative CT scan demonstrated a median lung volume increase of 88%.

CONCLUSION

 Mortality in ADT patients is high. However, LTE is a feasible and safe surgical approach, which could improve clinical conditions and survival rate. Survived patients showed postoperatively less oxygen requirement and improved clinical conditions.

Uncovering the burden of hidden ciliopathies in the 100 000 Genomes Project: a reverse phenotyping approach

BACKGROUND

The 100 000 Genomes Project (100K) recruited National Health Service patients with eligible rare diseases and cancer between 2016 and 2018. PanelApp virtual gene panels were applied to whole genome sequencing data according to Human Phenotyping Ontology (HPO) terms entered by recruiting clinicians to guide focused analysis.

METHODS

We developed a reverse phenotyping strategy to identify 100K participants with pathogenic variants in nine prioritised disease genes (BBS1, BBS10, ALMS1, OFD1, DYNC2H1, WDR34, NPHP1, TMEM67, CEP290), representative of the full phenotypic spectrum of multisystemic primary ciliopathies. We mapped genotype data 'backwards' onto available clinical data to assess potential matches against phenotypes. Participants with novel molecular diagnoses and key clinical features compatible with the identified disease gene were reported to recruiting clinicians.

RESULTS

We identified 62 reportable molecular diagnoses with variants in these nine ciliopathy genes. Forty-four have been reported by 100K, 5 were previously unreported and 13 are new diagnoses. We identified 11 participants with unreportable, novel molecular diagnoses, who lacked key clinical features to justify reporting to recruiting clinicians. Two participants had likely pathogenic structural variants and one a deep intronic predicted splice variant. These variants would not be prioritised for review by standard 100K diagnostic pipelines.

CONCLUSION

Reverse phenotyping improves the rate of successful molecular diagnosis for unsolved 100K participants with primary ciliopathies. Previous analyses likely missed these diagnoses because incomplete HPO term entry led to incorrect gene panel choice, meaning that pathogenic variants were not prioritised. Better phenotyping data are therefore essential for accurate variant interpretation and improved patient benefit.

Primary Cilia and Their Role in Acquired Heart Disease

Primary cilia are non-motile plasma membrane extrusions that display a variety of receptors and mechanosensors. Loss of function results in ciliopathies, which have been strongly linked with congenital heart disease, as well as abnormal development and function of most organ systems. Adults with congenital heart disease have high rates of acquired heart failure, and usually die from a cardiac cause. Here we explore primary cilia’s role in acquired heart disease. Intraflagellar Transport 88 knockout results in reduced primary cilia, and knockout from cardiac endothelium produces myxomatous degeneration similar to mitral valve prolapse seen in adult humans. Induced primary cilia inactivation by other mechanisms also produces excess myocardial hypertrophy and altered scar architecture after ischemic injury, as well as hypertension due to a lack of vascular endothelial nitric oxide synthase activation and the resultant left ventricular dysfunction. Finally, primary cilia have cell-to-cell transmission capacity which, when blocked, leads to progressive left ventricular hypertrophy and heart failure, though this mechanism has not been fully established. Further research is still needed to understand primary cilia’s role in adult cardiac pathology, especially heart failure.

A curious case of asphyxiating thoracic dystrophy in an adult

Asphyxiating thoracic dystrophy (ATD), also known as Jeune syndrome, is a rare autosomal recessive chondrodysplasia that most commonly manifests as shortening of long bones and ribs, as well as frequent extra-skeletal organ involvement. It is typically diagnosed in infancy or early childhood following episodes of respiratory distress or failure, in conjunction with characteristic physical findings, and is often fatal. The genetic heterogeneity of this disease, however, means there is varying severity of symptoms and physical manifestations. In this report, we describe a 57-year-old man with his first presentation of respiratory failure, with a history and physical findings consistent with ATD, a diagnosis previously unknown to the patient.

High diagnostic yield in skeletal ciliopathies using massively parallel genome sequencing, structural variant screening and RNA analyses

Skeletal ciliopathies are a heterogenous group of disorders with overlapping clinical and radiographic features including bone dysplasia and internal abnormalities. To date, pathogenic variants in at least 30 genes, coding for different structural cilia proteins, are reported to cause skeletal ciliopathies. Here, we summarize genetic and phenotypic features of 34 affected individuals from 29 families with skeletal ciliopathies. Molecular diagnostic testing was performed using massively parallel sequencing (MPS) in combination with copy number variant (CNV) analyses and in silico filtering for variants in known skeletal ciliopathy genes. We identified biallelic disease-causing variants in seven genes: DYNC2H1, KIAA0753, WDR19, C2CD3, TTC21B, EVC, and EVC2. Four variants located in non-canonical splice sites of DYNC2H1, EVC, and KIAA0753 led to aberrant splicing that was shown by sequencing of cDNA. Furthermore, CNV analyses showed an intragenic deletion of DYNC2H1 in one individual and a 6.7 Mb de novo deletion on chromosome 1q24q25 in another. In five unsolved cases, MPS was performed in family setting. In one proband we identified a de novo variant in PRKACA and in another we found a homozygous intragenic deletion of IFT74, removing the first coding exon and leading to expression of a shorter message predicted to result in loss of 40 amino acids at the N-terminus. These findings establish IFT74 as a new skeletal ciliopathy gene. In conclusion, combined single nucleotide variant, CNV and cDNA analyses lead to a high yield of genetic diagnoses (90%) in a cohort of patients with skeletal ciliopathies.

First Report of Spinal Anesthesia for Cesarean Delivery in a Parturient With Jeune Syndrome: A Case Report

Jeune syndrome, also known as asphyxiating thoracic dystrophy, is a rare form of autosomal recessive skeletal dysplasia. Respiratory distress due to thoracic and lung dysplasia is the primary complication associated with this disorder in neonates. Women with Jeune syndrome seldom conceive and give birth, as only a few survive until adulthood. Herein, we report the world's first case of a cesarean delivery under spinal anesthesia in a pregnant woman with Jeune syndrome with a history of chest wall reconstruction and spinal fusion surgeries.

Thirteen Years' Progression of Macular Atrophy in a Patient With Jeune Syndrome

Jeune syndrome is a rare skeletal dysplasia with an associated retinal dystrophy. The authors describe a case of progressive bilateral macular atrophy (with multimodal imaging) in a patient with Jeune syndrome who was followed over 13 years. This case, confirmed with genetic testing, highlights the importance of characterizing the relationship between phenotype and genotype in this genetically heterogenous condition. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:107-109.].

Skeletal ciliopathies: a pattern recognition approach

Ciliopathy encompasses a diverse group of autosomal recessive genetic disorders caused by mutations in genes coding for components of the primary cilia. Skeletal ciliopathy forms a subset of ciliopathies characterized by distinctive skeletal changes. Common skeletal ciliopathies include Jeune asphyxiating thoracic dysplasia, Ellis-van Creveld syndrome, Sensenbrenner syndrome, and short-rib polydactyly syndromes. These disorders share common clinical and radiological features. The clinical hallmarks comprise thoracic hypoplasia with respiratory failure, body disproportion with a normal trunk length and short limbs, and severely short digits occasionally accompanied by polydactyly. Reflecting the clinical features, the radiological hallmarks consist of a narrow thorax caused by extremely short ribs, normal or only mildly affected spine, shortening of the tubular bones, and severe brachydactyly with or without polydactyly. Other radiological clues include trident ilia/pelvis and cone-shaped epiphysis. Skeletal ciliopathies are commonly associated with extraskeletal anomalies, such as progressive renal degeneration, liver disease, retinopathy, cardiac anomalies, and cerebellar abnormalities. In this article, we discuss the radiological pattern recognition approach to skeletal ciliopathies. We also describe the clinical and genetic features of skeletal ciliopathies that the radiologists should know for them to play an appropriate role in multidisciplinary care and scientific advancement of these complicated disorders.

Management of Congenital Heart Disease Associated with Ellis-van Creveld Short-rib Thoracic Dysplasia

OBJECTIVE

To evaluate clinical outcome of patients with Ellis-van Creveld syndrome (EVC) in whom congenital heart disease (CHD) repair was delayed intentionally to reduce the risk of postoperative respiratory morbidity and mortality.

STUDY DESIGN

This retrospective review of 51 EVC c.1886+5G>T homozygotes born between 2005 and 2014 focused on 18 subjects who underwent surgery for CHD, subdivided into early (mean, 1.3 months) vs delayed (mean, 50.1 months) repair.

RESULTS

Growth trajectories differed between control subjects and patients with EVC, and CHD was associated with slower weight gain. Relative to controls, infants with EVC had a 40%-75% higher respiratory rates (independent of CHD) accompanied by signs of compensated respiratory acidosis. Blood gases and respiratory rates approached normal values by age 4 years. Hemodynamically significant CHD was present in 23 children, 18 (78%) of whom underwent surgical repair. Surgery was performed at 1.3 ± 1.3 months for children born between 2005 and 2009 (n = 9) and 50.1 ± 40.2 months (P = .009) for children born between 2010 and 2014 (n = 9). The latter had shorter postoperative mechanical ventilation (1.1 ± 2.4 days vs 49.6 ± 57.1 days; P = .075), shorter intensive care duration of stay (16 ± 24 days vs 48.6 ± 44.2 days; P = .155), and no postoperative tracheostomies (vs 60%; P = .028) or deaths (vs 44%; P = .082).

CONCLUSION

Among children with EVC and possibly other short-rib thoracic dysplasias, delayed surgical repair of CHD reduces postoperative morbidity and improves survival. Respiratory rate serves as a simple indicator for optimal timing of surgical repair.

Anesthetic Management of a Child With Jeune Syndrome for Tracheotomy: A Case Report

Jeune syndrome is a rare autosomal-recessive skeletal disorder. Anesthetic management of these patients is often difficult because of thoracic and lung hypoplasia. A 5-month-old boy with Jeune syndrome was scheduled to undergo a tracheotomy. Despite 5-minute preoxygenation with continuous positive airway pressure, the patient's oxygen saturation rapidly dropped during the induction of anesthesia. The continuous positive airway pressure should have been titrated to effective tidal volume during preoxygenation to recruit the patient's functional residual capacity and to prevent desaturation. During tracheotomy, volume-controlled ventilation with a high respiratory rate and sufficient inspiratory time effectively improved the patient's respiratory status.

Mechanisms for nonmitotic activation of Aurora-A at cilia

Overexpression of the Aurora kinase A (AURKA) is oncogenic in many tumors. Many studies of AURKA have focused on activities of this kinase in mitosis, and elucidated the mechanisms by which AURKA activity is induced at the G2/M boundary through interactions with proteins such as TPX2 and NEDD9. These studies have informed the development of small molecule inhibitors of AURKA, of which a number are currently under preclinical and clinical assessment. While the first activities defined for AURKA were its control of centrosomal maturation and organization of the mitotic spindle, an increasing number of studies over the past decade have recognized a separate biological function of AURKA, in controlling disassembly of the primary cilium, a small organelle protruding from the cell surface that serves as a signaling platform. Importantly, these activities require activation of AURKA in early G1, and the mechanisms of activation are much less well defined than those in mitosis. A better understanding of the control of AURKA activity and the role of AURKA at cilia are both important in optimizing the efficacy and interpreting potential downstream consequences of AURKA inhibitors in the clinic. We here provide a current overview of proteins and mechanisms that have been defined as activating AURKA in G1, based on the study of ciliary disassembly.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

[Infant respiratory distress revealing Jeune syndrome]

Jeune syndrome (asphyxiating thoracic dystrophy) is a rare autosomal recessive osteochondrodysplasia with a variable degree of severity, clinically characterized by respiratory distress with a narrow chest and limb shortness. The reported incidence is one to five in 500,000 live births. Most patients develop severe respiratory failure during the first 2 years of life, leading to death in 60-80 % of cases. Survivors may suffer from renal, hepatic, or pancreatic complications. Expanding thoracic surgery can be used for severe cases. We describe the case of an 18-month-old boy who developed mild respiratory distress. The patient showed typical radiological features of Jeune syndrome: narrow thorax with short ribs and trident appearance of the pelvis. This case underscores the value of the right interpretation of the chest radiograph of the infant with a respiratory distress syndrome.

Ciliopathies: Genetics in Pediatric Medicine

Ciliary disorders, which are also referred to as ciliopathies, are a group of hereditary disorders that result from dysfunctional cilia. The latter are cellular organelles that stick up from the apical plasma membrane. Cilia have important roles in signal transduction and facilitate communications between cells and their surroundings. Ciliary disruption can result in a wide variety of clinically and genetically heterogeneous disorders with overlapping phenotypes. Because cilia occur widespread in our bodies many organs and sensory systems can be affected when they are dysfunctional. Ciliary disorders may be isolated or syndromic, and common features are cystic liver and/or kidney disease, blindness, neural tube defects, brain anomalies and intellectual disability, skeletal abnormalities ranging from polydactyly to abnormally short ribs and limbs, ectodermal defects, obesity, situs inversus, infertility, and recurrent respiratory tract infections. In this review, we summarize the features, frequency, morbidity, and mortality of each of the different ciliopathies that occur in pediatrics. The importance of genetics and the occurrence of genotype-phenotype correlations are indicated, and advances in gene identification are discussed. The use of next-generation sequencing by which a gene panel or all genes can be screened in a single experiment is highlighted as this technology significantly lowered costs and time of the mutation detection process in the past. We discuss the challenges of this new technology and briefly touch upon the use of whole-exome sequencing as a diagnostic test for ciliary disorders. Finally, a perspective on the future of genetics in the context of ciliary disorders is provided.

Spinal correction of scoliosis in Jeune syndrome: a report of two cases

Background

Jeune syndrome (asphyxiating thoracic dystrophy) is an autosomal recessive disorder with constriction and narrowing of the thorax. To our knowledge, there are no reports regarding spinal deformity and correction in Jeune syndrome. Herein, we report two cases of spinal correction in patients with Jeune syndrome, and review the literature.

Case Presentation

We experienced cases of spinal scoliosis in an adolescent boy and a young adult woman, both with Jeune syndrome. Their spinal deformities had progressed by the time they came to our hospital for surgical correction. After preoperative evaluation of their general condition, including respiratory function in detail to confirm that they could undergo surgery, we treated both cases with posterior spinal correction and fusion. Spinal correction was performed safely and there were no severe complications, including respiratory depression, associated with surgery, and relatively satisfactory correction was obtained in both cases. In case 1, coronal deformity was corrected from 70° to 36° and from 82° to 42°, respectively. In case 2, Cobb angle was corrected from 52° to 20° and from 55° to 21°.

Conclusions

Posterior spinal correction can be performed safely in young patients with Jeune syndrome who have survived their infant stage and matured without a severe general condition.

Thoracic Insufficiency Syndrome

Thoracic insufficiency syndrome (TIS) is a broad grouping of disorders that have a substantial impact on the chest wall, spine, and in many situations, both. While the conditions are varied, they share a potentially substantial impact on respiratory capacity and development over time and a presentation and need for intervention that is often in early childhood. Addressing these conditions has required a new paradigm that involves both deformity correction and a preservation of growth capacity. While there are now a number of options to treat severe spinal deformity early in life, when the deformity causes or is caused by a chest wall deformity, the Vertical Expandable Prosthetic Titanium Rib(VEPTR) is able to support surgical correction of both. The skeletal correction is often quite dramatic, but the functional measurements of quality of life and pulmonary function often do not show as dramatic and improvement, but consistently show a stabilization indicating control of the progressive thoracospinal disorder that produced TIS.

Management of Thoracic Insufficiency Syndrome in Patients With Jeune Syndrome Using the 70 mm Radius Vertical Expandable Prosthetic Titanium Rib

BACKGROUND

Jeune syndrome (JS) often results in lethal thoracic insufficiency syndrome. Since 1991, vertical expandable prosthetic titanium rib Dynamic PosteroLateral Expansion Thoracoplasty was used at our institution for treatment of JS. This study assesses the safety and efficacy of this procedure.

METHODS

Twenty-four JS patients were treated, 2 lost to follow-up, 17 with a minimum of 2-year follow-up retrospectively reviewed for clinical course: Assisted Ventilation Rate, respiratory rate, capillary blood gases, pulmonary function testings, and complications. Upright anteroposterior/lateral radiographs were measured for Cobb angle, kyphosis, lordosis, thoracic width, and thoracic/lumbar spinal height. Computed tomography scan lung volumes were obtained in 12 patients.

RESULTS

Mean age at initial implant was 23 months (7 to 62 mo) with an average 8.4 years (2.3 to 15.6 y) of follow-up. Average chest width increased from 121 to 168 mm at follow-up (P<0.001). Preoperatively, 7/17 (41%) patients had scoliosis. The remainder developed scoliosis during treatment, 8 requiring additional implants. Thoracic and lumbar spinal height was normal preoperatively and stayed normal during treatment. Thoracic kyphosis/lumbar lordosis was stable. Average computed tomography scan total lung volumes increased 484 to 740 mm3 (P<0.001), and Assisted Ventilation Rate status tended to improve (P=0.07). Average forced vital capacity was 34% predicted at first test and 27% predicted at last follow-up. Early demise after surgery was common with multisystem disease. Mean respiratory rate decreased from 35 to 24 bpm at last follow-up (P<0.05). Survival rate of the 22 patients was 68%. Migration of the rib cradles/titanium slings occurred in 12 patients, superficial infections in 5 patients, deep infections in 4 patients, and wound dehiscence in 5 patients. Infection rate was 4.6% per procedure.

CONCLUSIONS

The survival rate in JS with surgery was nearly 70% (compared with 70% to 80% mortality without treatment) with less ventilator dependence. Both C1 stenosis and scoliosis are common in JS. Spinal height in JS is normal. Complications are frequent, but tolerable in view of the clinical gains and increase in survival.

Unmasking the ciliopathies: craniofacial defects and the primary cilium

Over the past decade, the primary cilium has emerged as a pivotal sensory organelle that acts as a major signaling hub for a number of developmental signaling pathways. In that time, a vast number of proteins involved in trafficking and signaling have been linked to ciliary assembly and/or function, demonstrating the importance of this organelle during embryonic development. Given the central role of the primary cilium in regulating developmental signaling, it is not surprising that its dysfunction results in widespread defects in the embryo, leading to an expanding class of human congenital disorders known as ciliopathies. These disorders are individually rare and phenotypically variable, but together they affect virtually every vertebrate organ system. Features of ciliopathies that are often overlooked, but which are being reported with increasing frequency, are craniofacial abnormalities, ranging from subtle midline defects to full-blown orofacial clefting. The challenge moving forward is to understand the primary mechanism of disease given the link between the primary cilium and a number of developmental signaling pathways (such as hedgehog, platelet-derived growth factor, and WNT signaling) that are essential for craniofacial development. Here, we provide an overview of the diversity of craniofacial abnormalities present in the ciliopathy spectrum, and reveal those defects in common across multiple disorders. Further, we discuss the molecular defects and potential signaling perturbations underlying these anomalies. This provides insight into the mechanisms leading to ciliopathy phenotypes more generally and highlights the prevalence of widespread dysmorphologies resulting from cilia dysfunction.

Antenatal Diagnosis of Jeune Syndrome (Asphyxiating Thoracic Dysplasia) with Micromelia and Facial Dysmorphism on Second-Trimester Ultrasound

Background

Jeune syndrome is a rare congenital malformation with a reported incidence of 1 in 100,000–130,000 live births. Thoracic hypoplasia is the most striking abnormality of this disorder. Here we report a case of Jeune syndrome with marked thoracic hypoplasia, micromelia and facial dysmorphism, which was diagnosed on a second-trimester antenatal real-time three-dimensional ultrasound.

Case Report

A 24-year-old primigravida came for routine anomaly scan at 19 weeks of gestation. Transabdominal grey scale and real time 3D ultrasound (US) was done with GE Logiq P5 with curvilinear array transducers (4C and 4D3C-L). US findings were consistent with the diagnosis of Jeune syndrome (Asphyxiating thoracic dysplasia).

Conclusions

Jeune syndrome is an extremely rare congenital disorder with a spectrum of abnormalities of which thoracic hypoplasia is the most striking. It can be diagnosed on early antenatal US by its characteristic skeletal and morphological features which can guide further management of pregnancy in form of termination or preparation for surgical correction of the deformity.

Systemic diseases associated with retinal dystrophies

Inherited retinal degeneration (IRD) may occur in isolation or as part of a multi-systemic condition. Ocular manifestations may be the presenting symptom of a syndromic disease and can include retinitis pigmentosa, cone-rod dystrophy, or maculopathy. Alternatively, patients affected with syndromic disease may already have other systemic manifestations at the time retinal disease is diagnosed. Some of these systemic diseases can cause significant morbidity. Here, we review several of these syndromic IRDs and their underlying genetic causes. Early recognition and referral for systemic evaluation and surveillance may lead to early intervention and an improved outcome. Obtaining a molecular diagnosis can be beneficial in securing a definitive diagnosis, especially in cases with atypical presentations. A genetic diagnosis may also be informative with regard to prognosis and potential therapies. Effective management and rehabilitation for patients with syndromic retinal dystrophy requires a comprehensive genetic-based team approach involving patients, family members, ophthalmologists, primary care physicians, and geneticists.

Autopsy observations in lethal short-rib polydactyly syndromes

The short rib-polydactyly syndromes are a heterogeneous group of lethal autosomal recessive disorders (SRP I-IV), which result from cellular ciliary dysfunction during embryogenesis. Diagnosis is conventionally based on radiographic imaging. Since 1976, postmortem investigations of 5 affected fetuses or stillbirths have been undertaken and the visceral abnormalities have been documented. These anomalies are discussed in the context of prenatal differential diagnosis and prognostication following imaging in pregnancy and at autopsy following miscarriage or stillbirth.

Primary thoraco-spinal disorders of childhood

Primary structural deformities of the spine and thorax were at one time rare and reportable in case series. With the development of new "growth friendly" implantable devices, children with these disorders are living longer and receiving both surgical and pulmonary care. As a result, there has been growing interest in the functional cardiopulmonary consequences of these deformities, the current surgical and non-surgical treatments, and the role of long-term supportive care. This article reviews current literature in this rapidly changing field, where new devices are developed and outcomes are changing. The respiratory consequences of early-onset thoraco-spinal disorders are emphasized and the roles of the pulmonologist and surgeons are discussed. There are more questions than answers as no long-term outcome data yet exists.

Mutations in CSPP1 cause primary cilia abnormalities and Joubert syndrome with or without Jeune asphyxiating thoracic dystrophy

Joubert syndrome (JBTS) is a recessive ciliopathy in which a subset of affected individuals also have the skeletal dysplasia Jeune asphyxiating thoracic dystrophy (JATD). Here, we have identified biallelic truncating CSPP1 (centrosome and spindle pole associated protein 1) mutations in 19 JBTS-affected individuals, four of whom also have features of JATD. CSPP1 mutations explain ∼5% of JBTS in our cohort, and despite truncating mutations in all affected individuals, the range of phenotypic severity is broad. Morpholino knockdown of cspp1 in zebrafish caused phenotypes reported in other zebrafish models of JBTS (curved body shape, pronephric cysts, and cerebellar abnormalities) and reduced ciliary localization of Arl13b, further supporting loss of CSPP1 function as a cause of JBTS. Fibroblasts from affected individuals with CSPP1 mutations showed reduced numbers of primary cilia and/or short primary cilia, as well as reduced axonemal localization of ciliary proteins ARL13B and adenylyl cyclase III. In summary, CSPP1 mutations are a major cause of the Joubert-Jeune phenotype in humans; however, the mechanism by which these mutations lead to both JBTS and JATD remains unknown.

Jeune syndrome: considerations for management of asphyxiating thoracic dystrophy

Jeune syndrome (JS), or asphyxiating thoracic dystrophy, is a rare genetic disorder characterized by a small, narrow thorax, with associated shortening of limbs. Children with JS present with variable degrees of respiratory distress, frequently lethal in the neonatal period. Other associated complications include renal, hepatic, gastrointestinal, and retinal dysfunction. Management focuses on stabilization and support of respiratory function. Treatment may be palliative in nature or corrective. In recent years, the advance in surgical treatment of the thoracic hypoplasia in JS offers hope to those families with a child suffering from the syndrome. Even with increased research into treatment of this disorder, prognosis is usually poor. Comorbidities associated with JS lead to serious organ dysfunction in later years. Families who have a child with JS need genetic counseling and education focusing on the seriousness of the disorder, the risks and benefits of treatment, and the lifelong needs of those with JS.

Mouse models of ciliopathies: the state of the art

The ciliopathies are an apparently disparate group of human diseases that all result from defects in the formation and/or function of cilia. They include disorders such as Meckel-Grüber syndrome (MKS), Joubert syndrome (JBTS), Bardet-Biedl syndrome (BBS) and Alström syndrome (ALS). Reflecting the manifold requirements for cilia in signalling, sensation and motility, different ciliopathies exhibit common elements. The mouse has been used widely as a model organism for the study of ciliopathies. Although many mutant alleles have proved lethal, continued investigations have led to the development of better models. Here, we review current mouse models of a core set of ciliopathies, their utility and future prospects.