Surface Reconstruction of the Pediatric Larynx via Structure from Motion Photogrammetry: A Pilot Study.

Endoscopy is the gold standard for characterizing pediatric airway disorders, however, it is limited for quantitative analysis due to lack of three-dimensional (3D) vision and poor stereotactic depth perception. We utilize structure from motion (SfM) photogrammetry, to reconstruct 3D surfaces of pathologic and healthy pediatric larynges from monocular two-dimensional (2D) endoscopy. Models of pediatric subglottic stenosis were 3D printed and airway endoscopies were simulated. 3D surfaces were successfully reconstructed from endoscopic videos of all models using an SfM analysis toolkit. Average subglottic surface error between SfM reconstructed surfaces and 3D printed models was 0.65 mm as measured by Modified Hausdorff Distance. Average volumetric similarity between SfM surfaces and printed models was 0.82 as measured by Jaccard Index. SfM can be used to accurately reconstruct 3D surface renderings of the larynx from 2D endoscopy video. This technique has immense potential for use in quantitative analysis of airway geometry and virtual surgical planning.

Intraventricular B7-H3 CAR T Cells for Diffuse Intrinsic Pontine Glioma: Preliminary First-in-Human Bioactivity and Safety.

Diffuse intrinsic pontine glioma (DIPG) remains a fatal brainstem tumor demanding innovative therapies. As B7-H3 (CD276) is expressed on central nervous system (CNS) tumors, we designed B7-H3-specific chimeric antigen receptor (CAR) T cells, confirmed their preclinical efficacy, and opened BrainChild-03 (NCT04185038), a first-in-human phase I trial administering repeated locoregional B7-H3 CAR T cells to children with recurrent/refractory CNS tumors and DIPG. Here, we report the results of the first three evaluable patients with DIPG (including two who enrolled after progression), who received 40 infusions with no dose-limiting toxicities. One patient had sustained clinical and radiographic improvement through 12 months on study. Patients exhibited correlative evidence of local immune activation and persistent cerebrospinal fluid (CSF) B7-H3 CAR T cells. Targeted mass spectrometry of CSF biospecimens revealed modulation of B7-H3 and critical immune analytes (CD14, CD163, CSF-1, CXCL13, and VCAM-1). Our data suggest the feasibility of repeated intracranial B7-H3 CAR T-cell dosing and that intracranial delivery may induce local immune activation. SIGNIFICANCE: This is the first report of repeatedly dosed intracranial B7-H3 CAR T cells for patients with DIPG and includes preliminary tolerability, the detection of CAR T cells in the CSF, CSF cytokine elevations supporting locoregional immune activation, and the feasibility of serial mass spectrometry from both serum and CSF. This article is highlighted in the In This Issue feature, p. 1.

Changes to pediatric brain tumors in 2021 World Health Organization classification of tumors of the central nervous system.

New tumor types are continuously being described with advances in molecular testing and genomic analysis resulting in better prognostics, new targeted therapy options and improved patient outcomes. As a result of these advances, pathological classification of tumors is periodically updated with new editions of the World Health Organization (WHO) Classification of Tumors books. In 2021, WHO Classification of Tumors of the Central Nervous System, 5th edition (CNS5), was published with major changes in pediatric brain tumors officially recognized including pediatric gliomas being separated from adult gliomas, ependymomas being categorized based on anatomical compartment and many new tumor types, most of them seen in children. Additional general changes, such as tumor grading now being done within tumor types rather than across entities and changes in definition of glioblastoma, are also relevant to pediatric neuro-oncology practice. The purpose of this manuscript is to highlight the major changes in pediatric brain tumors in CNS5 most relevant to radiologists. Additionally, brief descriptions of newly recognized entities will be presented with a focus on imaging findings.

Non-inferiority of a non-gadolinium-enhanced magnetic resonance imaging follow-up protocol for isolated optic pathway gliomas.

BACKGROUND: Pediatric patients with optic pathway gliomas (OPGs) typically undergo a large number of follow-up MRI brain exams with gadolinium-based contrast media (GBCM), which have been associated with gadolinium tissue retention. Therefore, careful consideration of GBCM use in these children is warranted. OBJECTIVE: To investigate whether GBCM is necessary for OPG MR imaging response assessment using a blinded, non-inferiority, multi-reader study. MATERIALS AND METHODS: We identified children with OPG and either stable disease or change in tumor size on MRI using a regional cancer registry serving the U.S. Pacific Northwest. For each child, the two relevant, consecutive MRI studies were anonymized and standardized into two imaging sets excluding or including GBCM-enhanced images. Exam pairs were compiled from 42 children with isolated OPG (19 with neurofibromatosis type 1), from a population of 106 children with OPG. We included 28 exam pairs in which there was a change in size between exams. Seven pediatric radiologists measured tumor sizes during three blinded sessions, spaced by at least 1 week. The first measuring session excluded GBCM-enhanced sequences; the others did not. The primary endpoint was intra-reader agreement for ≥ 25% change in axial cross-product measurement, using a 12% non-inferiority threshold. RESULTS: Analysis demonstrated an overall 1.2% difference (95% confidence interval, -3.2% to 5.5%) for intra-reader agreement using a non-GBCM-enhanced protocol and background variability. CONCLUSION: A non-GBCM-enhanced protocol was non-inferior to a GBCM-enhanced protocol for assessing change in size of isolated OPGs on follow-up MRI exams.

Accuracy and Reliability of 4D-CT and Flexible Laryngoscopy in Upper Airway Evaluation in Robin Sequence.

OBJECTIVES: To evaluate the performance of 4-dimensional computed tomography (4D-CT) in assessing upper airway obstruction (UAO) in patients with Robin sequence (RS) and compare the accuracy and reliability of 4D-CT and flexible fiber-optic laryngoscopy (FFL). STUDY DESIGN: Prospective survey of retrospective clinical data. SETTING: Single, tertiary care pediatric hospital. METHODS: At initial and 30-day time points, a multidisciplinary group of 11 clinicians who treat RS rated UAO severity in 32 sets of 4D-CT visualizations and FFL videos (dynamic modalities) and static CT images. Raters assessed UAO at the velopharynx and oropharynx (1 = none to 5 = complete) and noted confidence levels of each rating. Intraclass correlation and Krippendorff alpha were used to assess intra- and interrater reliability, respectively. Accuracy was assessed by comparing clinician ratings with quantitative percentage constriction (QPC) ratings, calculated based on 4D-CT airway cross-sectional area. Results were compared using Wilcoxon rank-sum and signed-rank tests. RESULTS: There was similar intrarater agreement (moderate to substantial) with 4D-CT and FFL, and both demonstrated fair interrater agreement. Both modalities underestimated UAO severity, although 4D-CT ratings were significantly more accurate, as determined by QPC similarity, than FFL (-1.06 and -1.46 vs QPC ratings, P = .004). Overall confidence levels were similar for 4D-CT and FFL, but other specialists were significantly less confident in FFL ratings than were otolaryngologists (2.25 and 3.92, P < .0001). CONCLUSION: Although 4D-CT may be more accurate in assessing the degree of UAO in patients with RS, 4D-CT and FFL assessments demonstrate similar reliability. Additionally, 4D-CT may be interpreted with greater confidence by nonotolaryngologists who care for these patients.

Evaluating the Utility of Routine Computed Tomography Scans after Cranial Vault Reconstruction for Children with Craniosynostosis.

BACKGROUND: Postoperative computed tomography scans allow for evaluation of the structural results of cranial vault reconstruction and potential surgical concerns. The authors evaluated the clinical utility of routine postoperative scans to identify relevant surgical findings in children treated for craniosynostosis. METHODS: The authors conducted a retrospective study of postoperative computed tomography reports for patients with craniosynostosis following cranial vault reconstruction during a 9-year period at their tertiary care pediatric hospital. They categorized postoperative computed tomography findings as typical, atypical, or indeterminate. Images with reported indeterminate or atypical findings were reviewed and verified by a pediatric neuroradiologist and a pediatric neurological surgeon. Clinical outcomes of patients with abnormal postoperative images were assessed with chart review for clinical relevance. RESULTS: Postoperative computed tomography radiology reports for 548 operations in 506 participants were included. Most participants had single-suture craniosynostosis (89 percent), were male (64 percent), and under 1 year of age (78 percent). Surgically concerning scans were described in 52 reports (<9.5 percent), and the research team's pediatric neuroradiologist confirmed abnormal findings in 36 (6.5 percent). Potentially relevant abnormal findings included subdural blood (n = 18), subarachnoid blood (n = 4), intraparenchymal findings (n = 6), bone abnormalities (n = 5), vascular injury (n = 3), and increased ventricular size (n = 2). Most cases with abnormal findings did not require additional observation nor intervention. Only three cases (of 548; 0.55 percent) required further intervention, which included additional medical management (n = 2) and return to the operating room (n = 1). CONCLUSION: Abnormal findings on routine computed tomography scans after cranial vault reconstruction are uncommon and rarely result in an urgent surgical or medical intervention. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, IV.

Automated atlas-based segmentation for skull base surgical planning.

PURPOSE: Computational surgical planning tools could help develop novel skull base surgical approaches that improve safety and patient outcomes. This defines a need for automated skull base segmentation to improve the usability of surgical planning software. The objective of this work was to design and validate an algorithm for atlas-based automated segmentation of skull base structures in individual image sets for skull base surgical planning. METHODS: Advanced Normalization Tools software was used to construct a synthetic CT template from 6 subjects, and skull base structures were manually segmented to create a reference atlas. Landmark registration followed by Elastix deformable registration was applied to the template to register it to each of the 30 trusted reference image sets. Dice coefficient, average Hausdorff distance, and clinical usability scoring were used to compare the atlas segmentations to those of the trusted reference image sets. RESULTS: The mean for average Hausdorff distance for all structures was less than 2 mm (mean for 95th percentile Hausdorff distance was less than 5 mm). For structures greater than 2.5 mL in volume, the average Dice coefficient was 0.73 (range 0.59-0.82), and for structures less than 2.5 mL in volume the Dice coefficient was less than 0.7. The usability scoring survey was completed by three experts, and all structures met the criteria for acceptable effort except for the foramen spinosum, rotundum, and carotid artery, which required more than minor corrections. CONCLUSION: Currently available open-source algorithms, such as the Elastix deformable algorithm, can be used for automated atlas-based segmentation of skull base structures with acceptable clinical accuracy and minimal corrections with the use of the proposed atlas. The first publicly available CT template and anterior skull base segmentation atlas being released (available at this link: http://hdl.handle.net/1773/46259 ) with this paper will allow for general use of automated atlas-based segmentation of the skull base.

4D Computed Tomography for Dynamic Upper Airway Evaluation in Robin Sequence.

Thorough assessment of dynamic upper airway obstruction (UAO) in Robin sequence (RS) is critical, but traditional evaluation modalities have significant limitations. Four-dimensional computed tomography (4D-CT) is promising in that it enables objective and quantitative evaluation throughout all phases of respiration. However, there exist few protocols or analysis tools to assist in obtaining and interpreting the vast amounts of obtained data. A protocol and set of data analysis tools were developed to enable quantification and visualization of dynamic 4D-CT data. This methodology was applied to a sample case at 2 time points. In the patient with RS, overall increases in normalized airway caliber were observed from 5 weeks to 1 year. There was, however, continued dynamic obstruction at all airway levels, though objective measures of UAO did improve at the nasopharynx and oropharynx. Use of 4D-CT and novel analyses provide additional quantitative information to evaluate UAO in patients with RS.

A phase 3 randomized clinical trial using a once-weekly glucagon-like peptide-1 receptor agonist in adolescents and young adults with hypothalamic obesity.

AIM: To evaluate the efficacy, safety and tolerability of a glucagon-like peptide-1 receptor agonist (GLP-1 RA) in patients with hypothalamic obesity (HO). MATERIALS AND METHODS: A two-arm, randomized, multicentre, double-blind, placebo-controlled trial was conducted in 10- to 25-year-olds with hypothalamic injury following intracranial tumour and HO. Participants were randomized to once-weekly subcutaneous injections of a GLP-1 RA exenatide 2 mg (ExQW) or placebo for 36 weeks. The primary efficacy endpoint was 36-week % change in body mass index (BMI). Secondary outcomes included change in body composition (by dual energy x-ray absorptiometry). RESULTS: Forty-two participants were randomized to ExQW (n = 23) or placebo (n = 19). Participants were 5 ± 2 years (mean ± SD) postdiagnosis and development of HO (BMI 37.3 ± 7.1 kg/m2 ). In intention-to-treat analysis, the effect of 36-week ExQW vs. placebo on % Δ BMI was not significant (estimated treatment difference -1.7 ± 1.8%, 95% CI -4.1 to 0.6%, P = .40); however, total body fat mass was reduced (estimated treatment difference -3.1 ± 1.4 kg, 95% CI -5.7 to -0.4 kg, P = .02). There was a significant reduction in waist circumference (estimated effect of treatment -3.5 [95% CI -5.5 to -1.6] cm, P = .004). All patients treated with placebo increased % of adipose tissue, while 50% treated with ExQW had reductions (P < .001). Mean HbA1c, glucose tolerance and serum lipids did not change significantly with therapy. ExQW was well tolerated. The most frequent adverse events were transient gastrointestinal disturbances (ExQW vs. placebo: nausea 6/23 vs. 3/18, vomiting 4/23 vs. 4/18 and diarrhoea 7/23 vs. 3/18). CONCLUSIONS: GLP-1 RAs are a promising and safe treatment to improve or stabilize HO in children and young adults.

Surveillance magnetic resonance imaging for isolated optic pathway gliomas: is gadolinium necessary?

BACKGROUND: Pediatric optic pathway gliomas are typically indolent but have a variable clinical course. Treatment is dictated by symptoms and changes on contrast-enhanced MRI examinations. Gadolinium retention in children has motivated parsimonious use of gadolinium-based contrast agents. OBJECTIVES: To determine surveillance MR factors that motivate changes in tumor-directed therapies and extrapolate cost-efficacy of a non-contrast follow-up protocol. MATERIALS AND METHODS: Using an imaging database search we identified children with isolated optic pathway gliomas and ≥3 follow-up contrast-enhanced MRIs. We reviewed medical records and imaging for: (1) coincident changes on contrast-enhanced MRI and tumor-directed therapy, (2) demographics and duration of follow-up, (3) motivations for intervention, (4) assessment of gadolinium-based contrast agents' utility and (5) health care utilization data. We assessed cost impact in terms of relative value unit (RVU) burden. RESULTS: We included 17 neurofibromatosis type 1 (NF1) and 21 non-NF1 patients who underwent a median 16.9 and 24.3 cumulative contrast-enhanced MR exams over 7.7 years and 8.1 years of follow-up, respectively. Eight children (one with NF1) had intervention based on contrast-enhanced MR findings alone. For these eight, increased tumor size was the only common feature, and it was apparent on non-contrast T2 sequences. For the median patient, a non-contrast follow-up protocol could result in 15.9 (NF1) and 23.3 (non-NF1) fewer gadolinium-based contrast agent administrations, and a 39% lower yearly RVU burden. CONCLUSION: Pediatric patients with isolated optic pathway gliomas undergo a large number of routine contrast-enhanced MR follow-up exams. Gadolinium might not be needed for these exams to inform management decisions. Secondary benefits of a non-contrast follow-up protocol include decreased cost and risk to the patient.

Oxytocin and Naltrexone Successfully Treat Hypothalamic Obesity in a Boy Post-Craniopharyngioma Resection.

Context: Hypothalamic obesity, a treatment-resistant condition common to survivors of craniopharyngioma (CP), is strongly associated with a poor quality of life in this population. Oxytocin (OT), a hypothalamic neuropeptide, has been shown to play a role in the regulation of energy balance and to have anorexigenic effects in animal studies. Naltrexone (NAL), an opiate antagonist, has been shown to deter hedonic eating and to potentiate OT's effects. Design: In this parent-observed study, we tested the administration of intranasal OT for 10 weeks (phase 1), followed by a combination of intranasal OT and NAL for 38 weeks (phase 2) in a 13-year-old male with confirmed hypothalamic obesity and hyperphagia post-CP resection. Treatment resulted in 1) reduction in body mass index (BMI) z score from 1.77 to 1.49 over 10 weeks during phase 1; 2) reduction in BMI z score from 1.49 to 0.82 over 38 weeks during phase 2; 3) reduced hyperphagia during phases 1 and 2; 4) continued hedonic high-carbohydrate food-seeking in the absence of hunger during phases 1 and 2; and 5) sustained weight reduction during decreased parental monitoring and free access to unlocked food in the home during the last 10 weeks of phase 2. Conclusion: This successful intervention of CP-related hypothalamic obesity and hyperphagia by OT alone and in combination with NAL is promising for conducting future studies of this treatment-recalcitrant form of obesity.

Prevalence of Abnormal Magnetic Resonance Imaging Findings in Children with Persistent Symptoms after Pediatric Sports-Related Concussion.

A subset of patients experience persistent symptoms after pediatric concussion, and magnetic resonance imaging (MRI) is commonly used to evaluate for pathology. The utility of this practice is unclear. We conducted a retrospective cohort study to describe the MRI findings in children with concussion. A registry of all patients seen at our institution from January 2010 through March 2016 with pediatric sports-related concussion was cross-referenced with a database of radiographical studies. Radiology reports were reviewed for abnormal findings. Patients with abnormal computed tomographies or MRI scans ordered for reasons other than concussion were excluded. Among 3338 children identified with concussion, 427 underwent MRI. Only 2 (0.5%) had findings compatible with traumatic injury, consisting in both of microhemorrhage. Sixty-one patients (14.3%) had abnormal findings unrelated to trauma, including 24 nonspecific T2 changes, 15 pineal cysts, eight Chiari I malformations, and five arachnoid cysts. One child underwent craniotomy for a cerebellar hemangioblastoma after presenting with ataxia; another had cortical dysplasia resected after seizure. The 2 patients with microhemorrhage each had three previous concussions, significantly more than patients whose scans were normal (median, 1) or abnormal without injury (median, 1.5; p = 0.048). MRI rarely revealed intracranial injuries in children post-concussion, and the clinical relevance of these uncommon findings remains unclear. Abnormalities unrelated to trauma are usually benign. However, MRI should be thoughtfully considered in children who present with concerning or atypical symptoms.

Primary choriocarcinoma of the bilateral basal ganglia presenting in a teenaged male.

Primary intracranial choriocarcinoma (PICCC), a type of germ-cell tumor, is a very rare primary tumor of the central nervous system that generally arises in the pineal or suprasellar region. We present a case of a teenage boy with PICCC of the bilateral basal ganglia, an anatomic site for which we were unable to find the previous reports. We offer discussion of the differential diagnosis, imaging characteristics, and prognosis of PICCC and germ-cell tumors of the basal ganglia, in the hope that it will increase awareness and allow for early detection.

Prenatal diagnosis of Chudley-McCullough syndrome.

Chudley-McCullough syndrome (CMS) is an autosomal-recessive disorder characterized by a complex brain malformation and profound congenital sensorineural hearing loss. Postnatal brain imaging findings include ventriculomegaly, partial agenesis of corpus callosum, inferior cerebellar dysplasia, arachnoid cysts, and malformations of cortical development including frontal subcortical heterotopia and polymicrogyria. Prenatal diagnosis of CMS is important due to the markedly less severe neurodevelopmental prognosis compared to disorders with similar brain imaging findings. We report prenatal imaging features that help distinguish CMS from other disorders, including slit-like frontal horns, agenesis of the corpus callosum, frontal subcortical heterotopia, arachnoid cysts, and cerebellar dysplasia. © 2016 Wiley Periodicals, Inc.

Upper Airway Computed Tomography Measures and Receipt of Tracheotomy in Infants With Robin Sequence.

IMPORTANCE: Airway management in infants with Robin sequence is challenging. Objective upper airway measures associated with severe airway compromise requiring tracheotomy are needed to guide decision making. OBJECTIVES: To define objective upper airway measures in infants with Robin sequence from craniofacial computed tomography (CT) and to identify those measures in Robin sequence associated with tracheotomy. DESIGN, SETTING, AND PARTICIPANTS: A cohort study (2003 to 2014, over 1-year follow-up) of 37 infants with Robin sequence evaluated for surgical management and 37 selected age- and sex-matched controls without a craniofacial condition conducted in a pediatric institution's craniofacial center. MAIN OUTCOMES AND MEASURES: Define and compare CT-generated upper airway measures in these groups: infants with Robin sequence vs controls, and infants with Robin sequence with vs without tracheotomy. A negative difference signifies lower values for the Robin sequence and tracheotomy groups. Clinical data collected included age and height at time of CT scan, sex, tracheotomy presence, associated syndrome, and laboratory indicators of hypoventilation and hypoxemia. To evaluate interrater reliability, 2 raters performed each measurement in the Robin sequence group. RESULTS: In 74 infants, 17 of 28 measures were different between infants with Robin sequence and those in the control group. Tracheotomy was performed in 14 of 37 (38%) infants with Robin sequence. Infants with tracheotomy more commonly had associated syndromes (12 of 14 [86%] vs 11 of 23 [48%]) and a history of hypoventilation and hypoxemia (13 of 14 [93%] vs 15 of 23 [65%]). Five of the 11 measures associated with tracheotomy were reliable and simpler to measure with the following mean differences (95% CIs) between groups: tongue length, 0.87 (0.26 to 1.48); tongue position relative to palate, 0.83 (0.22 to 1.45); mandibular total length, -0.8 (-1.42 to -0.19); gonial angle, 0.71 (0.08 to 1.34); and inferior pogonial angle, 0.66 (0.02 to 1.29). Using a receiver operating characteristic analysis, a composite score of these 5 measures for predicting tracheotomy risk yielded an area under the curve of 0.83 and achieved 86% sensitivity and 74% specificity. CONCLUSIONS AND RELEVANCE: Computed tomography measures quantifying tongue position and mandibular configuration can identify infants with Robin sequence, and importantly, differentiate those who have severe upper airway compromise requiring tracheotomy. Following validation, these measures can be used for objective upper airway assessment and for expediting clinical decision-making in these challenging cases for which no such tools currently exist.

Pediatric Central Diabetes Insipidus: Brain Malformations Are Common and Few Patients Have Idiopathic Disease.

CONTEXT: Pediatric cohorts of central diabetes insipidus (CDI) have shown varying prevalences for the different causes of CDI, including idiopathic. OBJECTIVE: The objective of the study was to determine the causes of CDI at a pediatric tertiary care center and to characterize their clinical outcomes. DESIGN AND SETTING: All patients with CDI at Seattle Children's Hospital were identified and retrospectively analyzed. PATIENTS: From 2000 to 2013, 147 patients with CDI were encountered (mean age 7 y at diagnosis, mean follow-up 6.2 y). OUTCOME MEASURES: The different causes of CDI were grouped, and age of diagnosis, anterior pituitary hormone deficiencies (APHDs), and presence of the posterior pituitary bright spot (PPBS) were analyzed. Patients with idiopathic CDI had infundibular thickening measured using a systematic method. RESULTS: Brain malformations caused 24% of CDI cases, and 12.2% were idiopathic. Four of 22 patients with initially idiopathic CDI were diagnosed with an underlying condition, none occurring later than 2.5 years from diagnosis. APHDs were as common in the brain malformation group as they were in the tumor/infiltrative group (72% vs 85%; P = .09). The PPBS was present in at least 13% of patients and in 19% of those with brain malformations. Patients with idiopathic CDI and stalk thickening on the initial magnetic resonance imaging were more likely to have an underlying diagnosis (40% vs 0%; P = .03). CONCLUSIONS: Brain malformations were a more common cause of pediatric CDI than previously reported. These patients have a high rate of APHDs, and many have persistence of the PPBS. Idiopathic CDI is an uncommon diagnosis, and none of our patients were diagnosed with Langerhans cell histiocytosis or germinoma for more than 3 years from CDI diagnosis. Providers can consider less frequent magnetic resonance imaging after this time point. A systematic method of infundibular measurement on the initial magnetic resonance imaging may predict an underlying germinoma or Langerhans cell histiocytosis.

Exome sequencing identifies a recurrent de novo ZSWIM6 mutation associated with acromelic frontonasal dysostosis.

Acromelic frontonasal dysostosis (AFND) is a rare disorder characterized by distinct craniofacial, brain, and limb malformations, including frontonasal dysplasia, interhemispheric lipoma, agenesis of the corpus callosum, tibial hemimelia, preaxial polydactyly of the feet, and intellectual disability. Exome sequencing of one trio and two unrelated probands revealed the same heterozygous variant (c.3487C>T [p. Arg1163Trp]) in a highly conserved protein domain of ZSWIM6; this variant has not been seen in the 1000 Genomes data, dbSNP, or the Exome Sequencing Project. Sanger validation of the three trios confirmed that the variant was de novo and was also present in a fourth isolated proband. In situ hybridization of early zebrafish embryos at 24 hr postfertilization (hpf) demonstrated telencephalic expression of zswim6 and onset of midbrain, hindbrain, and retinal expression at 48 hpf. Immunohistochemistry of later-stage mouse embryos demonstrated tissue-specific expression in the derivatives of all three germ layers. qRT-PCR expression analysis of osteoblast and fibroblast cell lines available from two probands was suggestive of Hedgehog pathway activation, indicating that the ZSWIM6 mutation associated with AFND may lead to the craniofacial, brain and limb malformations through the disruption of Hedgehog signaling.

Parkin-mediated K63-linked polyubiquitination targets misfolded DJ-1 to aggresomes via binding to HDAC6.

Sequestration of misfolded proteins into pericentriolar inclusions called aggresomes is a means that cells use to minimize misfolded protein-induced cytotoxicity. However, the molecular mechanism by which misfolded proteins are recruited to aggresomes remains unclear. Mutations in the E3 ligase parkin cause autosomal recessive Parkinson's disease that is devoid of Lewy bodies, which are similar to aggresomes. Here, we report that parkin cooperates with heterodimeric E2 enzyme UbcH13/Uev1a to mediate K63-linked polyubiquitination of misfolded DJ-1. K63-linked polyubiquitination of misfolded DJ-1 serves as a signal for interaction with histone deacetylase 6, an adaptor protein that binds the dynein-dynactin complex. Through this interaction, misfolded DJ-1 is linked to the dynein motor and transported to aggresomes. Furthermore, fibroblasts lacking parkin display deficits in targeting misfolded DJ-1 to aggresomes. Our findings reveal a signaling role for K63-linked polyubiquitination in dynein-mediated transport, identify parkin as a key regulator in the recruitment of misfolded DJ-1 to aggresomes, and have important implications regarding the biogenesis of Lewy bodies.