Polymicrogyria

Natalie CrawfordKaren Inzana

D. Phillip Sponenberg

Virginia – Maryland Regional College of Veterinary MedicineBlacksburg, Virginia

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Polymicrogyria (also known as microgyria)

Malformation of the cerebral cortex Neuronal migration defect leading to

abnormal lamination Excessive production of gyri Associated with other brain malformations

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Veterinary Medicine

Ruminants Cattle

Sheep

Rats Experimentally induced

DogsPresented at SEVPAC 2008 –

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Historical Perspective

Van Winkle et. al. (1994) Four related Standard Poodle dogs with cortical blindness Young dogs (5-9 months)

Jurney et. al. (2008) Four un-related Standard Poodle dogs with cortical

blindness and behavioral abnormalities Three young dogs (3-4 months) One older dog (5 years)

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Allegro

3 month old male intact Standard Poodle

Decreased vision Noticed from 9 weeks of age

Abnormal behavior

Possible decreased hearing

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Diagnosis

Ophthalmic Examination No ophthalmic cause for blindness

Neurologic Examination Generalized or diffuse encephalopathy Cortical blindness

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Other Findings

Gross lesions - Definitive

Histologic lesions

Imaging (MRI) Not done in Allegro’s case

Brain Activity Monitoring (EEG) Not done in Allegro’s case

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Gross Findings

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Histologic Lesions

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Normal Nissl

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H&E (07-1996.4)

Polymicrogyria H & E

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Polymicrogyria Nissl

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Polymicrogyria Phenotype

Clinical Presentation Standard Poodles 0-6 months of age Cortical Blindness Gross lesions

Outcome Euthanasia

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Human Medicine

Frequent occurrence

Manifests with varying degrees of mental retardation, developmental delays and seizure activity

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Schulyer Hudson

Bilateral Persylvian Polymicrogyria Partial paralysis of

muscles of the face, jaws and throat

Learning difficulties Cerebral palsy Seizures

Genetic

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Literature

Veterinary Neuropathology, Summers B, et al. (1995)

Blindness Due to Polymicrogyria and Asymmetrical Dilation of the Lateral Ventricles in Standard Poodles, Van Winkle TJ, et al. (1994)

Neuropathology: A Reference Text of CNS Pathology, 2nd Ed., Ellison D, et al. (2004)

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Acknowledgements

D. Phillip Sponenberg Karen Inzana Carrie Jurney

Jurney C, et al. Polymicrogyria in Four Standard Poodles: A Case Series with Histopathologic, Electroencephalographic

and Magnetic Resonance Imaging Findings.

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Contributors

Jamie Haddad – UPenn Thomas Van Winkle – UPenn Andrew Miller – Cornell Andras Komaromy – UPenn Charles Vite - UPenn Gayle Johnson - Missouri Dennis O’Brien – Missouri

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Questions?

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