John R. R. Ostergaard

Dr. John R. R. Ostergaard

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2020 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Open access
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FPFélixe Pelletier
Félixe Pelletier
SPStefanie Perrier
Stefanie Perrier
FCFerdy K Cayami
Ferdy K Cayami
AMAmytice Mirchi
Amytice Mirchi
SSStephan Saikali
Stephan Saikali
GBGeneviève Bernard
Geneviève Bernard
Context 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date. Objective To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy. Design An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated. Setting This was a multicenter retrospective study using information collected from 3 predominant centers. Patients A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included. Main Outcome Measures Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts. Results The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients. Conclusions Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.

2 June 2020 in American Journal of Medical Genetics Part A
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Journal Article
Closed access
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KDKaroline Doser
Karoline Doser
EAElisabeth Wreford Andersen
Elisabeth Wreford Andersen
LKLine Kenborg
Line Kenborg
SDSusanne Oksbjerg Dalton
Susanne Oksbjerg Dalton
JJJens Richardt Møllegaard Jepsen
Jens Richardt Møllegaard Jepsen
PBPernille Envold Bidstrup
Pernille Envold Bidstrup

8 October 2015 in Frontiers in Neurology
Verified
Journal Article
Open access
JMJohn Michael
John Michael
KBKathleen Bogart
Kathleen Bogart
KTKristian Tylén
Kristian Tylén
JKJoel Krueger
Joel Krueger
MBMorten Bech
Morten Bech
RFRiccardo Fusaroli
Riccardo Fusaroli
In the exploratory study reported here, we tested the efficacy of an intervention designed to train teenagers with Möbius Syndrome (MS) to increase the use of alternative communication strategies (e.g. gestures) to compensate for their lack of facial expressiveness. Specifically, we expected the intervention to increase the level of rapport experienced in social interactions by our participants. In addition, we aimed to identify the mechanisms responsible for any such increase in rapport. In the study, five teenagers with MS interacted with three naïve participants without MS before the intervention, and with three different naïve participants without MS after the intervention. Rapport was assessed by self-report and by behavioral coders who rated videos of the interactions. Individual nonverbal behavior was assessed via behavioral coders, while verbal behavior was automatically extracted from the sound files. Alignment was assessed using cross recurrence quantification analysis and mixed effects models. The results showed that observer-coded rapport was greater after the intervention, whereas self-reported rapport did not change significantly. Observer-coded gesture and expressivity increased in participants with and without MS, while overall linguistic alignment decreased. Fidgeting and repetitiveness of verbal behavior also decreased in both groups. In sum, the intervention may impact nonverbal and verbal behavior in participants with and without MS, increasing rapport as well as overall gesturing, while decreasing alignment.

22 November 2016 in Circulation
Verified
Journal Article
Open access
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MLMichelle Z. Leisner
Michelle Z. Leisner
NMNicolas L. Madsen
Nicolas L. Madsen
JOJohn R. R. Ostergaard
John R. R. Ostergaard
JWJessica Graus Woo
Jessica Graus Woo
BMBradley S. Marino
Bradley S. Marino
MOMorten S. Olsen
Morten S. Olsen

25 August 2020 in Neuropathology and Applied Neurobiology
Verified
Journal Article
Open access
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HNHemanth Ramesh Nelvagal
Hemanth Ramesh Nelvagal
JDJoshua T. Dearborn
Joshua T. Dearborn
JOJohn R. R. Ostergaard
John R. R. Ostergaard
MSMark Sands
Mark Sands
JCJonathan D. Cooper
Jonathan D. Cooper
Aim: To understand the progression of CLN1 disease and develop effective therapies we need to characterize early sites of pathology. Therefore, we performed a comprehensive evaluation of the nature and timing of early CLN1 disease pathology in the spinal cord, which appears especially vulnerable, and how this may affect behaviour.Methods: We measured the spinal volume and neuronal number, and quantified glial activation, lymphocyte infiltration and oligodendrocyte maturation, as well as cytokine profile analysis during the early stages of pathology in Ppt1‐deficient (Ppt1−/−) mouse spinal cords. We then performed quantitative gait analysis and open‐field behaviour tests to investigate the behavioural correlates during this period.Results: We detected significant microglial activation in Ppt1−/− spinal cords at 1 month. This was followed by astrocytosis, selective interneuron loss, altered spinal volumes and oligodendrocyte maturation at 2 months, before significant storage material accumulation and lymphocyte infiltration at 3 months. The same time course was apparent for inflammatory cytokine expression that was altered as early as one month. There was a transient early period at 2 months when Ppt1−/− mice had a significantly altered gait that resembles the presentation in children with CLN1 disease. This occurred before an anticipated decline in overall locomotor performance across all ages.Conclusion: These data reveal disease onset 2 months (25% of life‐span) earlier than expected, while spinal maturation is still ongoing. Our multi‐disciplinary data provide new insights into the spatio‐temporal staging of CLN1 pathogenesis during ongoing postnatal maturation, and highlight the need to deliver therapies during the presymptomatic period.

6 January 2017 in Orphanet Journal of Rare Diseases
Verified
Journal Article
Open access
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LPLine Kjeldgaard Pedersen
Line Kjeldgaard Pedersen
RMRikke Damkjær Maimburg
Rikke Damkjær Maimburg
JHJens Michael Hertz
Jens Michael Hertz
HGHans Gjørup
Hans Gjørup
TPThomas Klit Pedersen
Thomas Klit Pedersen
JOJohn R. R. Ostergaard
John R. R. Ostergaard
Moebius Sequence (MS) is a rare disorder defined by bilateral congenital paralysis of the abducens and facial nerves in combination with various odontological, craniofacial, ophthalmological and orthopaedic conditions. The aetiology is still unknown; but both genetic (de novo mutations) and vascular events in utero are reported. The purpose of present study was through a multidisciplinary clinical approach to examine children diagnosed with Moebius-like symptoms. Ten children underwent odontological, ophthalmological, obstetric, paediatric, orthopaedic, genetic, radiological and photographical evaluation. Five patients maintained the diagnosis of MS according to the diagnostic criteria. All five patients had bilateral facial and abducens paralysis confirmed by ophthalmological examination. Three of five had normal brain MR imaging. Two had missing facial nerves and one had missing abducens nerves. The Strengths and Difficulties Questionnaire (SDQ) showed normal scores in three of five patients. Interestingly, two of five children were born to mothers with uterine abnormalities (unicornuate/bicornuate uterus). In the odontological examination three of five showed enamel hypomineralisation. All five had abnormal orofacial motor function and maxillary prognathism. Two patients had adactyly, syndactyly and brachydactyly. None of the five patients had Poland anomaly, hip dislocation or dysplasia but all had a mild degree of scoliosis. We observed congenital club-feet, calcaneovalgus deformities, macrodactyly of one or more toes or curly toes. Pedobarography showed plantar pressures within normal ranges. Adherence to standard diagnostic criteria is central in the diagnosis of MS. An accurate diagnosis is the basis for correct discussion of other relevant concomitant symptoms of MS, genetic testing and evaluation of prognosis. The multidisciplinary approach and adherence to diagnostic criteria taken in present study increases the knowledge on the relationship between genotype, phenotype and symptomatology of MS.