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1.
Article in English | MEDLINE | ID: mdl-38564656

ABSTRACT

ABSTRACT: Clinical education for nurse practitioner (NP) students is increasingly challenging. With fewer preceptors, lack of resources and time burden, finding clinical placements is a burdensome responsibility. Also, when students have multiple preceptors, there may be inconsistencies when evaluating students. With the change to competency-based education, consistency is crucial when evaluating NP students. Typical preceptorship with students is a 1:1:1 ratio: one student with one preceptor for one semester. The Dyad/Precepting to Optimize Development (POD) model has potential to improve clinical precepting. Precepting to optimize development refers to a consistent team of students, preceptors, and faculty over the course of the students' education. Dyad refers to two students with one preceptor. Students rotate in dyad pairs every 4-8 weeks with a consistent group of preceptors, and see these same preceptors again over the course of their educational journey. Preceptors met monthly to collaborate, discuss, and learn. This article reports on the outcomes of a mixed-methods feasibility study that occurred over a year. The students, preceptors, and faculty report satisfaction with the model. Several themes arose during analysis of focus group sessions. Those themes were as follows: safe learning environment; everyone teaches, everyone learns; growth mindset; teaming culture and the POD structure is essential to the dyad. In conclusion, developing a different approach to precepting is essential to meet national provider needs. The Dyad/POD model provides consistency for development and evaluation of the NP student.

2.
J Pediatr Orthop ; 44(1): e61-e68, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-37867374

ABSTRACT

BACKGROUND: Pantothenate kinase-associated neurodegeneration (PKAN) is a rare, neurodegenerative disorder that manifests with progressive loss of ambulation and refractory dystonia, especially in the early-onset classic form. This leads to osteopenia and stress on long bones, which pose an increased risk of atraumatic femur fractures. The purpose of this study is to describe the unique challenges in managing femur fractures in PKAN and the effect of disease manifestations on surgical outcomes. METHODS: A retrospective case review was conducted on 5 patients (ages 10 to 20 y) with PKAN with a femur fracture requiring surgical intervention. Data regarding initial presentation, surgical treatment, complications, and outcomes were obtained. RESULTS: All patients were non-ambulatory, with 4 of 5 patients sustaining an atraumatic femur fracture in the setting of dystonia episode. One patient had an additional contralateral acetabular fracture. Postoperatively, 4 of the 5 patients sustained orthopaedic complications requiring surgical revision, with 3 of these secondary to dystonia. Overall, 4 required prolonged hospitalization in the setting of refractory dystonia. CONCLUSION: Femur fractures in PKAN present distinct challenges for successful outcomes. A rigid intramedullary rod with proximal and distal interlocking screws is most protective against surgical complications associated with refractory dystonia occurring during the postoperative period. Multidisciplinary planning for postoperative care is essential and may include aggressive sedation and pain management to decrease the risk of subsequent injuries or complications. LEVEL OF EVIDENCE: Level IV.


Subject(s)
Dystonia , Pantothenate Kinase-Associated Neurodegeneration , Spinal Fractures , Humans , Pantothenate Kinase-Associated Neurodegeneration/complications , Pantothenate Kinase-Associated Neurodegeneration/therapy , Dystonia/complications , Dystonia/therapy , Retrospective Studies , Femur
3.
bioRxiv ; 2023 Sep 13.
Article in English | MEDLINE | ID: mdl-37745522

ABSTRACT

Beta-Propeller Protein-Associated Neurodegeneration (BPAN) is one of the commonest forms of Neurodegeneration with Brain Iron Accumulation, caused by mutations in the gene encoding the autophagy-related protein, WDR45. The mechanisms linking autophagy, iron overload and neurodegeneration in BPAN are poorly understood and, as a result, there are currently no disease-modifying treatments for this progressive disorder. We have developed a patient-derived, induced pluripotent stem cell (iPSC)-based midbrain dopaminergic neuronal cell model of BPAN (3 patient, 2 age-matched controls and 2 isogenic control lines) which shows defective autophagy and aberrant gene expression in key neurodegenerative, neurodevelopmental and collagen pathways. A high content imaging-based medium-throughput blinded drug screen using the FDA-approved Prestwick library identified 5 cardiac glycosides that both corrected disease-related defective autophagosome formation and restored BPAN-specific gene expression profiles. Our findings have clear translational potential and emphasise the utility of iPSC-based modelling in elucidating disease pathophysiology and identifying targeted therapeutics for early-onset monogenic disorders.

4.
Pediatr Neurol ; 138: 1-4, 2023 01.
Article in English | MEDLINE | ID: mdl-36270151

ABSTRACT

BACKGROUND: Down syndrome regression disorder (DSRD) is characterized by the sudden loss of adaptive function, cognitive-executive function, and language with abnormal sleep and/or motor control. METHODS: Clinical, laboratory, and imaging data from three individuals with DSRD and iron on brain imaging were reviewed. RESULTS: Three patients with Down syndrome presented with new onset of flat affect, depression, reduced speech, and other neurological symptoms consistent with DSRD. Magnetic resonance imaging showed abnormal iron accumulation in the basal ganglia, as well as calcification in two cases. Molecular diagnostic testing for neurodegeneration with brain iron accumulation was negative in the two individuals tested. CONCLUSIONS: These individuals presented suggest that a subset of individuals with DSRD have abnormal brain iron accumulation. Motor control symptoms reported in DSRD, such as stereotypies and parkinsonism, may reflect this basal ganglia involvement. The presence of abnormal brain iron should not delay or preclude diagnosis and treatment for DSRD.


Subject(s)
Down Syndrome , Humans , Down Syndrome/complications , Down Syndrome/pathology , Iron , Brain/diagnostic imaging , Brain/pathology , Basal Ganglia/diagnostic imaging , Basal Ganglia/pathology , Magnetic Resonance Imaging
5.
Dermatol Surg ; 49(1): 17-24, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36533790

ABSTRACT

BACKGROUND: Treatments for solar lentigines include topical and physical therapies, including chemical peels, lasers, intense pulsed light, and cryotherapy. A direct comparison of treatment methods and their efficacy is lacking. OBJECTIVE: To compare treatment efficacy and adverse events for different treatment modalities for lentigines. METHODS: Cochrane, MEDLINE, and Embase databases were searched on August 25, 2021. Studies were included if they met our predetermined population, intervention, comparator, outcomes, study design framework. Results are presented in narrative form. RESULTS: Forty-eight articles met the inclusion criteria, representing a total of 1,763 patients. Overall, combination-based treatments showed the greatest frequency of cases with complete response (65%, n = 299/458), followed by laser-based treatments (43%, n = 395/910), topical retinoids (21%, n = 12/57), cryotherapy (15%, n = 25/169), and peels (6%, n = 8/125). Adverse events occurred most commonly while using topical retinoids (82%, n = 23/28), followed by combination-based treatments (39%, n = 184/466), cryotherapy (33%, n = 47/144), laser-based treatments (23%, n = 173/738), and peels (19%, n = 21/110). CONCLUSION: Despite heterogeneity of included study designs, patient populations, treatment regimens, and outcome measures, our results suggest that combination-based treatments and laser-based treatments were the most efficacious treatment modalities. Although cryotherapy was previously considered first-line, our results show that it has substantially lower pooled response rates compared with other treatment modalities.


Subject(s)
Chemexfoliation , Lentigo , Photochemotherapy , Humans , Lentigo/therapy , Cryotherapy/adverse effects , Cryotherapy/methods , Photochemotherapy/methods , Retinoids
6.
7.
Pediatr Dermatol ; 38 Suppl 2: 13-19, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34338358

ABSTRACT

Barriers to healthcare access are healthcare inequities that have been widely studied across different medical specialties. No studies have previously evaluated the state of barriers to healthcare access research in pediatric dermatology. A systematic review was conducted to examine the types of barriers identified within pediatric dermatology literature. Relevant information was extracted and categorized into the themes of systemic, sociocultural, or individual barriers. The systemic barriers we found include finances, wait times, and geography. The sociocultural barriers included culture beliefs and communication. Patient beliefs and health knowledge were found as individual barriers. The small number and limited scope of studies we identified suggest that barriers to healthcare access in pediatric dermatology remain an understudied topic. Additional research is needed to further characterize these barriers to dermatologic care, as well as the impact of any interventions designed to overcome them.


Subject(s)
Dermatology , Child , Health Services Accessibility , Humans
8.
Dev Med Child Neurol ; 63(12): 1402-1409, 2021 12.
Article in English | MEDLINE | ID: mdl-34347296

ABSTRACT

This review provides recommendations for the evaluation and management of individuals with beta-propeller protein-associated neurodegeneration (BPAN). BPAN is one of several neurodegenerative disorders with brain iron accumulation along with pantothenate kinase-associated neurodegeneration, PLA2G6-associated neurodegeneration, mitochondrial membrane protein-associated neurodegeneration, fatty acid hydroxylase-associated neurodegeneration, and COASY protein-associated neurodegeneration. BPAN typically presents with global developmental delay and epilepsy in childhood, which is followed by the onset of dystonia and parkinsonism in mid-adolescence or adulthood. BPAN is an X-linked dominant disorder caused by pathogenic variants in WDR45, resulting in a broad clinical phenotype and imaging spectrum. This review, informed by an evaluation of the literature and expert opinion, discusses the clinical phenotype and progression of the disease, imaging findings, epilepsy features, and genetics, and proposes an approach to the initial evaluation and management of disease manifestations across the life span in individuals with BPAN. What this paper adds The complex epilepsy profile of beta-propeller protein-associated neurodegeneration (BPAN) often resolves in adolescence. The treatment for an individual with BPAN is supportive, with attention to sleep disorders, complex epilepsy, and behavioral problems. Individuals with BPAN have shifting needs throughout their life span requiring multidisciplinary care.


Subject(s)
Brain/pathology , Iron/metabolism , Neurodegenerative Diseases/diagnosis , Brain/metabolism , Disease Management , Humans , Neurodegenerative Diseases/metabolism , Neurodegenerative Diseases/pathology
9.
Pediatr Dermatol ; 38 Suppl 2: 106-109, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34390037

ABSTRACT

Melanoma is rare in pediatric patients and even more so in those with darker Fitzpatrick skin types. Although risk factors for conventional melanoma are similar in both adult and pediatric cases, the presentation of melanoma in pediatric patients is often distinct from adults. Here, we describe a case of amelanotic ulcerated nodular melanoma with regional lymph node metastases treated with nivolumab in a patient with Fitzpatrick skin type VI.


Subject(s)
Melanoma, Amelanotic , Skin Neoplasms , Adult , Child , Humans , Melanoma, Amelanotic/diagnosis , Skin Neoplasms/drug therapy
10.
Ann Neurol ; 89(6): 1240-1247, 2021 06.
Article in English | MEDLINE | ID: mdl-33704825

ABSTRACT

A rapidly expanding catalog of neurogenetic disorders has encouraged a diagnostic shift towards early clinical whole exome sequencing (WES). Adult primary mitochondrial diseases (PMDs) frequently exhibit neurological manifestations that overlap with other nervous system disorders. However, mitochondrial DNA (mtDNA) is not routinely analyzed in standard clinical WES bioinformatic pipelines. We reanalyzed 11,424 exomes, enriched with neurological diseases, for pathogenic mtDNA variants. Twenty-four different mtDNA mutations were detected in 64 exomes, 11 of which were considered disease causing based on the associated clinical phenotypes. These findings highlight the diagnostic uplifts gained by analyzing mtDNA from WES data in neurological diseases. ANN NEUROL 2021;89:1240-1247.


Subject(s)
DNA, Mitochondrial/genetics , Mitochondrial Diseases/genetics , Nervous System Diseases/diagnosis , Nervous System Diseases/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Child, Preschool , Humans , Male , Middle Aged , Exome Sequencing , Young Adult
11.
Brain ; 143(11): 3242-3261, 2020 12 05.
Article in English | MEDLINE | ID: mdl-33150406

ABSTRACT

Heterozygous mutations in KMT2B are associated with an early-onset, progressive and often complex dystonia (DYT28). Key characteristics of typical disease include focal motor features at disease presentation, evolving through a caudocranial pattern into generalized dystonia, with prominent oromandibular, laryngeal and cervical involvement. Although KMT2B-related disease is emerging as one of the most common causes of early-onset genetic dystonia, much remains to be understood about the full spectrum of the disease. We describe a cohort of 53 patients with KMT2B mutations, with detailed delineation of their clinical phenotype and molecular genetic features. We report new disease presentations, including atypical patterns of dystonia evolution and a subgroup of patients with a non-dystonic neurodevelopmental phenotype. In addition to the previously reported systemic features, our study has identified co-morbidities, including the risk of status dystonicus, intrauterine growth retardation, and endocrinopathies. Analysis of this study cohort (n = 53) in tandem with published cases (n = 80) revealed that patients with chromosomal deletions and protein truncating variants had a significantly higher burden of systemic disease (with earlier onset of dystonia) than those with missense variants. Eighteen individuals had detailed longitudinal data available after insertion of deep brain stimulation for medically refractory dystonia. Median age at deep brain stimulation was 11.5 years (range: 4.5-37.0 years). Follow-up after deep brain stimulation ranged from 0.25 to 22 years. Significant improvement of motor function and disability (as assessed by the Burke Fahn Marsden's Dystonia Rating Scales, BFMDRS-M and BFMDRS-D) was evident at 6 months, 1 year and last follow-up (motor, P = 0.001, P = 0.004, and P = 0.012; disability, P = 0.009, P = 0.002 and P = 0.012). At 1 year post-deep brain stimulation, >50% of subjects showed BFMDRS-M and BFMDRS-D improvements of >30%. In the long-term deep brain stimulation cohort (deep brain stimulation inserted for >5 years, n = 8), improvement of >30% was maintained in 5/8 and 3/8 subjects for the BFMDRS-M and BFMDRS-D, respectively. The greatest BFMDRS-M improvements were observed for trunk (53.2%) and cervical (50.5%) dystonia, with less clinical impact on laryngeal dystonia. Improvements in gait dystonia decreased from 20.9% at 1 year to 16.2% at last assessment; no patient maintained a fully independent gait. Reduction of BFMDRS-D was maintained for swallowing (52.9%). Five patients developed mild parkinsonism following deep brain stimulation. KMT2B-related disease comprises an expanding continuum from infancy to adulthood, with early evidence of genotype-phenotype correlations. Except for laryngeal dysphonia, deep brain stimulation provides a significant improvement in quality of life and function with sustained clinical benefit depending on symptoms distribution.


Subject(s)
Dystonic Disorders/genetics , Histone-Lysine N-Methyltransferase/genetics , Adolescent , Adult , Child , Child, Preschool , Chromosome Deletion , Cohort Studies , Computer Simulation , Deep Brain Stimulation , Disease Progression , Dystonic Disorders/therapy , Endocrine System Diseases/complications , Endocrine System Diseases/genetics , Female , Fetal Growth Retardation/genetics , Gait Disorders, Neurologic/etiology , Gait Disorders, Neurologic/therapy , Humans , Laryngeal Diseases/etiology , Laryngeal Diseases/therapy , Male , Mutation , Mutation, Missense , Phenotype , Quality of Life , Treatment Outcome , Young Adult
12.
Front Neurol ; 11: 1024, 2020.
Article in English | MEDLINE | ID: mdl-33013674

ABSTRACT

Most neurodegeneration with brain iron accumulation (NBIA) disorders can be distinguished by identifying characteristic changes on magnetic resonance imaging (MRI) in combination with clinical findings. However, a significant number of patients with an NBIA disorder confirmed by genetic testing have MRI features that are atypical for their specific disease. The appearance of specific MRI patterns depends on the stage of the disease and the patient's age at evaluation. MRI interpretation can be challenging because of heterogeneously acquired MRI datasets, individual interpreter bias, and lack of quantitative data. Therefore, optimal acquisition and interpretation of MRI data are needed to better define MRI phenotypes in NBIA disorders. The stepwise approach outlined here may help to identify NBIA disorders and delineate the natural course of MRI-identified changes.

13.
J Child Neurol ; 35(4): 259-264, 2020 03.
Article in English | MEDLINE | ID: mdl-31823681

ABSTRACT

BACKGROUND: Pantothenate kinase-associated neurodegeneration is characterized by severe, progressive dystonia. This study aims to describe the reported usage of cannabis products among children with pantothenate kinase-associated neurodegeneration. METHODS: A cross-sectional, 37-item survey was distributed in April 2019 to the families of 44 children who participate in a clinical registry of individuals with pantothenate kinase-associated neurodegeneration. RESULTS: We received 18 responses (40.9% response rate). Children were a mean of 11.0 (SD 4.3) years old. The 15 respondents with dystonia or spasticity were on a median of 2 tone medications (range 0-9). Seven children had ever used cannabis (38.9%). The most common source of information about cannabis was other parents. Children who had ever used cannabis were on more tone medications, were more likely to have used opiates, were less likely to be able to roll, and less likely to sit comfortably, than children who had never used cannabis. Four children reported moderate or significant improvement in dystonia with cannabis. Other areas reported to be moderate or significantly improved were pain (n = 3), sleep (n = 4), anxiety (n = 3), and behavior (n = 2). Adverse effects included sadness (n = 1), agitation/behavior change (n = 1), and tiredness (n = 1). CONCLUSION: Cannabis use was commonly reported among children with pantothenate kinase-associated neurodegeneration whose parents responded to a survey, particularly when many other dystonia treatments had been tried. Physicians should be aware that parents may treat their child with severe, painful dystonia with cannabis. Placebo-controlled studies of products containing cannabidiol and 9-tetrahydrocannabinol are needed for pediatric tone disorders.


Subject(s)
Medical Marijuana/therapeutic use , Pantothenate Kinase-Associated Neurodegeneration/drug therapy , Adolescent , Child , Child, Preschool , Cross-Sectional Studies , Female , Gastrostomy , Humans , Male , Medical Marijuana/administration & dosage , Treatment Outcome
14.
Dermatol Surg ; 46(2): 240-246, 2020 02.
Article in English | MEDLINE | ID: mdl-31453910

ABSTRACT

BACKGROUND: Facial aging is a multifactorial process. Accordingly, expert opinion has largely been unanimous in that multimodal treatment targeting various aspects of the aging face provides superior results. However, there is a lack of studies exploring patient response. OBJECTIVE: To compare patient retention between triple multimodal facial rejuvenation treatment (neuromodulator, filler, and energy-based therapy) and monotherapy (neuromodulator alone). METHODS: A retrospective, multicenter (the United States, Canada, and Germany) study was performed. Cases were retrieved from July 2015 to June 2016. The study compared patients who had undergone monotherapy (neuromodulator), combined multimodal treatment (neuromodulator, filler, and energy-based therapy on the same day), and sequential multimodal treatment (neuromodulator, filler, and energy-based therapy over a 1-year period). Retention rates were calculated. RESULTS: A total of 509 patients were included: monotherapy (300), sequential multimodal treatment (93), and combined multimodal treatment (116). Patient retention was significantly higher in the combined multimodal treatment group compared with the monotherapy and sequential multimodal treatment groups (p < .001). Subgroup analysis revealed similar trends at all sites. CONCLUSION: Based on retention rates, patients are more likely to return to the clinic when multiple treatment modalities are used during 1 encounter. These data further solidify the importance of multimodal therapy for both the provider and the patient.


Subject(s)
Cosmetic Techniques/statistics & numerical data , Dermal Fillers/administration & dosage , Rejuvenation , Retention in Care/statistics & numerical data , Transcutaneous Electric Nerve Stimulation/statistics & numerical data , Adult , Aged , Aged, 80 and over , Canada , Combined Modality Therapy/methods , Combined Modality Therapy/statistics & numerical data , Face/physiology , Female , Germany , Humans , Male , Middle Aged , Patient Satisfaction , Retrospective Studies , Skin Aging/drug effects , Skin Aging/physiology , Treatment Outcome , United States , Young Adult
15.
Brain Commun ; 2(2): fcaa178, 2020.
Article in English | MEDLINE | ID: mdl-33629063

ABSTRACT

Bilateral basal ganglia abnormalities on MRI are observed in a wide variety of childhood disorders. MRI pattern recognition can enable rationalization of investigations and also complement clinical and molecular findings, particularly confirming genomic findings and also enabling new gene discovery. A pattern recognition approach in children with bilateral basal ganglia abnormalities on brain MRI was undertaken in this international multicentre cohort study. Three hundred and five MRI scans belonging to 201 children with 34 different disorders were rated using a standard radiological scoring proforma. In addition, literature review on MRI patterns was undertaken in these 34 disorders and 59 additional disorders reported with bilateral basal ganglia MRI abnormalities. Cluster analysis on first MRI findings from the study cohort grouped them into four clusters: Cluster 1-T2-weighted hyperintensities in the putamen; Cluster 2-T2-weighted hyperintensities or increased MRI susceptibility in the globus pallidus; Cluster 3-T2-weighted hyperintensities in the globus pallidus, brainstem and cerebellum with diffusion restriction; Cluster 4-T1-weighted hyperintensities in the basal ganglia. The 34 diagnostic categories included in this study showed dominant clustering in one of the above four clusters. Inflammatory disorders grouped together in Cluster 1. Mitochondrial and other neurometabolic disorders were distributed across clusters 1, 2 and 3, according to lesions dominantly affecting the striatum (Cluster 1: glutaric aciduria type 1, propionic acidaemia, 3-methylglutaconic aciduria with deafness, encephalopathy and Leigh-like syndrome and thiamine responsive basal ganglia disease associated with SLC19A3), pallidum (Cluster 2: methylmalonic acidaemia, Kearns Sayre syndrome, pyruvate dehydrogenase complex deficiency and succinic semialdehyde dehydrogenase deficiency) or pallidum, brainstem and cerebellum (Cluster 3: vigabatrin toxicity, Krabbe disease). The Cluster 4 pattern was exemplified by distinct T1-weighted hyperintensities in the basal ganglia and other brain regions in genetically determined hypermanganesemia due to SLC39A14 and SLC30A10. Within the clusters, distinctive basal ganglia MRI patterns were noted in acquired disorders such as cerebral palsy due to hypoxic ischaemic encephalopathy in full-term babies, kernicterus and vigabatrin toxicity and in rare genetic disorders such as 3-methylglutaconic aciduria with deafness, encephalopathy and Leigh-like syndrome, thiamine responsive basal ganglia disease, pantothenate kinase-associated neurodegeneration, TUBB4A and hypermanganesemia. Integrated findings from the study cohort and literature review were used to propose a diagnostic algorithm to approach bilateral basal ganglia abnormalities on MRI. After integrating clinical summaries and MRI findings from the literature review, we developed a prototypic decision-making electronic tool to be tested using further cohorts and clinical practice.

16.
EMBO Mol Med ; 11(12): e10489, 2019 12.
Article in English | MEDLINE | ID: mdl-31660701

ABSTRACT

Pantothenate kinase-associated neurodegeneration (PKAN) is an inborn error of CoA metabolism causing dystonia, parkinsonism, and brain iron accumulation. Lack of a good mammalian model has impeded studies of pathogenesis and development of rational therapeutics. We took a new approach to investigating an existing mouse mutant of Pank2 and found that isolating the disease-vulnerable brain revealed regional perturbations in CoA metabolism, iron homeostasis, and dopamine metabolism and functional defects in complex I and pyruvate dehydrogenase. Feeding mice a CoA pathway intermediate, 4'-phosphopantetheine, normalized levels of the CoA-, iron-, and dopamine-related biomarkers as well as activities of mitochondrial enzymes. Human cell changes also were recovered by 4'-phosphopantetheine. We can mechanistically link a defect in CoA metabolism to these secondary effects via the activation of mitochondrial acyl carrier protein, which is essential to oxidative phosphorylation, iron-sulfur cluster biogenesis, and mitochondrial fatty acid synthesis. We demonstrate the fidelity of our model in recapitulating features of the human disease. Moreover, we identify pharmacodynamic biomarkers, provide insights into disease pathogenesis, and offer evidence for 4'-phosphopantetheine as a candidate therapeutic for PKAN.


Subject(s)
Coenzyme A/metabolism , Dopamine/metabolism , Iron/metabolism , Pantetheine/analogs & derivatives , Pantothenate Kinase-Associated Neurodegeneration/drug therapy , Pantothenate Kinase-Associated Neurodegeneration/metabolism , Animals , Biomarkers/metabolism , Genotype , Mice , Pantetheine/pharmacology , Pantetheine/therapeutic use , Phosphotransferases (Alcohol Group Acceptor)/metabolism
17.
Mol Genet Genomic Med ; 7(7): e00736, 2019 07.
Article in English | MEDLINE | ID: mdl-31087512

ABSTRACT

BACKGROUND: Mitochondrial membrane protein-associated neurodegeneration (MPAN) is caused by pathogenic sequence variants in C19orf12. Autosomal recessive inheritance has been demonstrated. We present evidence of autosomal dominant MPAN and propose a mechanism to explain these cases. METHODS: Two large families with apparently dominant MPAN were investigated; additional singleton cases of MPAN were identified. Gene sequencing and multiplex ligation-dependent probe amplification were used to characterize the causative sequence variants in C19orf12. Post-mortem brain from affected subjects was examined. RESULTS: In two multi-generation non-consanguineous families, we identified different nonsense sequence variations in C19orf12 that segregate with the MPAN phenotype. Brain pathology was similar to that of autosomal recessive MPAN. We additionally identified a preponderance of cases with single heterozygous pathogenic sequence variants, including two with de novo changes. CONCLUSIONS: We present three lines of clinical evidence to demonstrate that MPAN can manifest as a result of only one pathogenic C19orf12 sequence variant. We propose that truncated C19orf12 proteins, resulting from nonsense variants in the final exon in our autosomal dominant cohort, impair function of the normal protein produced from the non-mutated allele via a dominant negative mechanism and cause loss of function. These findings impact the clinical diagnostic evaluation and counseling.


Subject(s)
Iron Metabolism Disorders/genetics , Membrane Proteins/genetics , Mitochondrial Proteins/genetics , Neuroaxonal Dystrophies/genetics , Adult , Brain , Codon, Nonsense/genetics , Cohort Studies , Family , Female , Genes, Dominant/genetics , Heterozygote , Humans , Iron Metabolism Disorders/metabolism , Male , Mitochondrial Membranes/metabolism , Mitochondrial Proteins/metabolism , Mutation , Neuroaxonal Dystrophies/metabolism , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/metabolism , Pedigree
20.
Mol Genet Metab ; 121(2): 180-189, 2017 06.
Article in English | MEDLINE | ID: mdl-28456385

ABSTRACT

Pantothenate Kinase-Associated Neurodegeneration (PKAN) is a form of Neurodegeneration with Brain Iron Accumulation (NBIA) associated with mutations in the pantothenate kinase 2 gene (PANK2). The PANK2 catalyzes the first step of coenzyme A (CoA) biosynthesis, a pathway producing an essential cofactor that plays a key role in energy and lipid metabolism. The majority of PANK2 mutations reduces or abolishes the activity of the enzyme. In around 10% of cases with PKAN, the presence of deformed red blood cells with thorny protrusions in the circulation has been detected. Changes in membrane protein expression and assembly during erythropoiesis were previously explored in patients with PKAN. However, data on red blood cell membrane phospholipid organization are still missing in this disease. In this study, we performed lipidomic analysis on red blood cells from Italian patients affected by PKAN with a particular interest in membrane physico-chemical properties. We showed an increased number of small red blood cells together with membrane phospholipid alteration, particularly a significant increase in sphingomyelin (SM)/phosphatidylcholine (PC) and SM/phosphatidylethanolamine (PE) ratios, in subjects with PKAN. The membrane structural abnormalities were associated with membrane fluidity perturbation. These morphological and functional characteristics of red blood cells in patients with PKAN offer new possible tools in order to shed light on the pathogenesis of the disease and to possibly identify further biomarkers for clinical studies.


Subject(s)
Erythrocyte Membrane/chemistry , Membrane Lipids/blood , Pantothenate Kinase-Associated Neurodegeneration/blood , Pantothenate Kinase-Associated Neurodegeneration/physiopathology , Phospholipids/blood , Adult , Biomarkers/blood , Brain/diagnostic imaging , Brain/pathology , Child , Erythrocyte Membrane/physiology , Female , Humans , Iron/metabolism , Magnetic Resonance Imaging , Male , Membrane Fluidity , Membrane Lipids/chemistry , Membrane Proteins/genetics , Mitochondria/enzymology , Mitochondria/ultrastructure , Mutation , Pantothenate Kinase-Associated Neurodegeneration/genetics , Phospholipids/chemistry , Young Adult
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