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dc.contributor.advisorWalker, Rob
dc.contributor.advisorSanderson, Gordon
dc.contributor.advisorKowal, Lionel
dc.contributor.authorMitchell, Logan Vaughan
dc.date.available2018-02-04T20:02:11Z
dc.date.copyright2018
dc.identifier.citationMitchell, L. V. (2018). SOPARIX Study – PHOX2A (ARIX) and PHOX2B Gene Analysis of a Cohort with Radiologically-Proven Congenital Superior Oblique Palsies (Thesis, Master of Ophthalmology). University of Otago. Retrieved from http://hdl.handle.net/10523/7838en
dc.identifier.urihttp://hdl.handle.net/10523/7838
dc.description.abstractIntroduction: Congenital superior oblique palsy (CSOP) remains enigmatic in terms of diagnosis, classification, and pathophysiology. Tendon abnormalities are commonly recognized intra-operatively, whilst recent orbital imaging advances find superior oblique (SO) muscle hypoplasia to be a key diagnostic feature. The relationship between these two features is unclear, but congenital superior oblique palsy may be a congenital cranial dysinnervation disorder (CCDD) – perhaps a milder variant of congenital fibrosis of the extra-ocular muscles type 2 (CFEOM2). Mutations in homeobox gene PHOX2A (ARIX) are found to cause CFEOM2. Polymorphisms in homologs PHOX2A and PHOX2B are reported among clinically diagnosed CSOP cases in Japan, including three familial cases. Aim: To describe polymorphisms in the PHOX2A and PHOX2B genes among a cohort of predominantly Caucasian Australians with radiologically-proven CSOP. Methods: Lionel Kowal routinely images the orbits of patients with cyclovertical strabismus in his private practice. Patients with radiologically-proven congenital superior oblique palsy were seen for repeat assessment by the investigator, and DNA samples were collected via saliva specimen. Coding sequences of PHOX2A and PHOX2B were amplified by polymerase chain reaction (PCR), then underwent Sanger sequencing. Sequences were compared to published genome and single nucleotide polymorphism (SNP) databases. Results: Thirty-five patients (average age 35.7 years) were included. Mean ipsilateral:contralateral SO diameter ratio on coronal CT or MRI images was 0.41 (range 0.1-0.67). Gene sequencing of PHOX2A and PHOX2B samples from these patients revealed a single heterozygous SNP of gene PHOX2A, C328T, representing a minor allele frequency (MAF) of 0.029 – a statistically insignificant difference to this SNP’s published MAF of 0.014. Conclusion: In this Australian cohort of radiologically-proven CSOP, sequencing of PHOX2A and PHOX2B revealed a single, recognized, SNP in line with published frequencies. This contrasted to previous literature studying different patient populations.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectophthalmology
dc.subjectstrabismus
dc.subjectsuperior oblique palsy
dc.subjectgenetics
dc.titleSOPARIX Study – PHOX2A (ARIX) and PHOX2B Gene Analysis of a Cohort with Radiologically-Proven Congenital Superior Oblique Palsies
dc.typeThesis
dc.date.updated2018-02-04T09:47:29Z
dc.language.rfc3066en
thesis.degree.disciplineDept of Medicine, Dunedin School of Medicine
thesis.degree.nameMaster of Ophthalmology
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.openaccessOpen
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