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14. A novel homeobox mutation in the PITX2 gene in a family with Axenfeld‐Rieger syndrome associated with brain, ocular, and dental phenotypes

Author

Idrees, Faisal, primary, Bloch‐Zupan, Agnes, additional, Free, Samantha L., additional, Vaideanu, Daniela, additional, Thompson, Pamela J., additional, Ashley, Paul, additional, Brice, Glen, additional, Rutland, Paul, additional, Bitner‐Glindzicz, Maria, additional, Khaw, Peng T., additional, Fraser, Scott, additional, Sisodiya, Sanjay M., additional, and Sowden, Jane C., additional

Published
2006
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16. SOX2 anophthalmia syndrome

Author

Ragge, Nicola K., primary, Lorenz, Birgit, additional, Schneider, Adele, additional, Bushby, Kate, additional, de Sanctis, Luisa, additional, de Sanctis, Ugo, additional, Salt, Alison, additional, Collin, J. Richard O., additional, Vivian, Anthony J., additional, Free, Samantha L., additional, Thompson, Pamela, additional, Williamson, Kathleen A., additional, Sisodiya, Sanjay M., additional, van Heyningen, Veronica, additional, and FitzPatrick, David R., additional

Published
2005
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20. Polymicrogyria and absence of pineal gland due to PAX6 mutation

Author

Mitchell, Tejal N., primary, Free, Samantha L., additional, Williamson, Kathleen A., additional, Stevens, John M., additional, Churchill, Amanda J., additional, Hanson, Isabel M., additional, Shorvon, Simon D., additional, Moore, Anthony T., additional, van Heyningen, Veronica, additional, and Sisodiya, Sanjay M., additional

Published
2003
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23. Deficient auditory interhemispheric transfer in patients with PAX6mutations

Author

Bamiou, Doris‐Eva, Musiek, Frank E., Sisodiya, Sanjay M., Free, Samantha L., Davies, Rosalyn A., Moore, Anthony, van Heyningen, Veronica, and Luxon, Linda M.

Abstract

PAX6mutations are associated with absence/hypoplasia of the anterior commissure and reduction in the callosal area in humans. Both of these structures contain auditory interhemispheric fibers. The aim of this study was to characterize central auditory function in patients with a PAX6mutation. We conducted central auditory tests (dichotic speech, pattern, and gaps in noise tests) on eight subjects with a PAX6mutation and eight age‐ and sex‐matched controls. Brain magnetic resonance imaging showed absent/hypoplastic anterior commissure in six and a hypoplastic corpus callosum in three PAX6subjects. The control group gave normal central auditory tests results. All the PAX6subjects gave abnormal results in at least two tests that require interhemispheric transfer, and all but one gave normal results in a test not requiring interhemispheric transfer. The left ear scores in the dichotic speech tests was significantly lower in the PAX6than in the control group. These results are consistent with deficient auditory interhemispheric transfer in patients with a PAX6mutation, which may be attributable to structural and/or functional abnormalities of the anterior commisure and corpus callosum, although the exact contribution of these two formations to our findings remains unclear. Our unique findings broaden the possible functions of PAX6to include neurodevelopmental roles in higher order auditory processing. Ann Neurol 2004

Published
2004
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24. Polymicrogyria and absence of pineal gland due to <TOGGLE>PAX6</TOGGLE> mutation

Author

Mitchell, Tejal N., Free, Samantha L., Williamson, Kathleen A., Stevens, John M., Churchill, Amanda J., Hanson, Isabel M., Shorvon, Simon D., Moore, Anthony T., and Heyningen, Veronica van

Abstract

Identification of genes involved in human cerebral development is important for our understanding of disorders with potential neurodevelopmental causes such as epilepsy and learning disability. Murine models suggest that PAX6 plays a key role in human brain development. With magnetic resonance imaging in 24 humans heterozygous for defined PAX6 mutations, we demonstrated widespread structural abnormalities including absence of the pineal gland and unilateral polymicrogyria. Ann Neurol 2003;53:658–663

Published
2003
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25. Reliable callosal measurement: population normative data confirm sex-related differences.

Author

Mitchell TN, Free SL, Merschhemke M, Lemieux L, Sisodiya SM, and Shorvon SD

Subjects
Adolescent, Adult, Aged, Dominance, Cerebral physiology, Female, Humans, Male, Middle Aged, Reference Values, Reproducibility of Results, Corpus Callosum anatomy & histology, Image Interpretation, Computer-Assisted, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods, Sex Characteristics
Abstract

Background and Purpose: Corpus callosal cross-sectional area (CCA) may be a clinical indicator of disease progression, but factors influencing callosal morphology in healthy subjects must be determined before comparisons can be made in patients. We sought to define a reliable and easily repeatable method for CCA measurement and to examine the effects of sex, age, handedness, and cerebral volume., Methods: Neurologically healthy volunteers (age range, 14-68 years; mean age, 32.6 years +/- 12.3 [SD]; 44 men, 56 women; 87 right handed) underwent conventional MR imaging. Data were reoriented in the image space to account for intersubject variations in head position before the midsagittal plane was defined by using midpoints of the anterior commissure (AC), posterior commissure (PC), and interhemispheric fissure (IF). Midsagittal CCA and total cerebral volume were measured and correlated with sex, age, and handedness., Results: The mean CCA was 6.27 cm(2) +/- 0.90. Women had a larger CCA proportional to cerebral volume (6.16 x 10(-3) cm(-1) vs 5.78 x 10(-3) cm(-1) in men; P =.02). The percentage difference for the CCA-cerebral volume from the group mean was +2.6% in women and -3.6% in men. Only a small linear relationship of CCA with cerebral volume was noted (r(2) = 0.15), and CCA was not significantly correlated with age or handedness., Conclusion: To our knowledge, this is the largest study of callosal area in a community-based sample of control subjects; such subjects provide controls for future studies. Our findings provide anatomic evidence of sex differences in interhemispheric connectivity. Much CCA variability is independent of cerebral volume.

Published
2003

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