Case study A rare case of congenital fibrosis of extraocular muscle type 1A due to KIF21A mutation with Marcus Gunn jaw-winking phenomenon Ay¸ se Kac ¸ar Bayram a , Hu ¨ seyin Per a,* , Jennifer Quon b,c,d , Mehmet Canpolat a , Ege U ¨ lgen b,c,d , Hakkı Do  gan e , Hakan Gumus a , Sefer Kumandas a , Nurettin Bayram f , Kaya Bilguvar g , Ahmet Okay C ¸a  glayan b,c,d,** a Department of Pediatrics, Division of Pediatric Neurology, Erciyes University, Faculty of Medicine, Kayseri, Turkey b Department of Neurosurgery, Yale School of Medicine, New Haven, USA c Department of Neurobiology, Yale School of Medicine, New Haven, USA d Department of Genetics, Yale School of Medicine, New Haven, USA e Department of Ophthalmology, Erciyes University, Faculty of Medicine, Kayseri, Turkey f Department of Ophthalmology, Research and Training Hospital, Kayseri, Turkey g Department of Genetics and Yale Center for Genome Analysis, Yale School of Medicine, New Haven, USA article info Article history: Received 13 May 2015 Received in revised form 16 June 2015 Accepted 24 June 2015 Keywords: KIF21A Marcus Gunn jaw-winking phenomenon CFEOM1 abstract Background: Congenital fibrosis of the extraocular muscles (CFEOM1) is classically a congenital, non-progressive, restrictive strabismus syndrome characterized by bilateral ptosis and ophthalmoplegia with an infraducted position of the globes. This autosomal dominant syndrome is caused by mutations in the KIF21A gene. Methods and results: In this report we describe a 5-year-old boy, and his mother, both of whom have a mutation in the KIF21A gene, who possesses typical features of CFEOM1 syndrome. Besides displaying typical features of CFEOM1, he demonstrated Marcus Gunn jaw-winking phenomenon. The patient additionally had a positive family history of such features. Conclusion: This is first report of the coexistence of CFEOM and Marcus Gunn jaw-winking phenomenon in a patient with a KIF21A mutation from Turkey. We explain the phenotypic findings associated with mutations in KIF21A including CFEOM1A and Marcus Gunn jaw- winking phenomenon. © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved. Abbreviations: CFEOM, Congenital fibrosis of the extraocular muscles; DNA, Deoxyribonucleic acid; KIF21A, Kinesin family member 21A; MG, Marcus Gunn jaw-winking phenomenon. * Corresponding author. Erciyes University Medical School, Department of Pediatric Neurology, Talas, Kayseri, Turkey. Tel.: þ90 (352) 2076666; fax: þ90 (352) 4375825. ** Corresponding author. Department of Neurosurgery, Yale School of Medicine, New Haven, CT 06510, USA. Tel.: þ1 203 737 6895; fax: þ1 203 785 7560. E-mail addresses: draysebayram@gmail.com (A. Kac ¸ar Bayram), huseyinper@yahoo.com (H. Per), Jennifer.quon@yale.edu (J. Quon), drmehmetcanpolat@gmail.com (M. Canpolat), egeulgen@gmail.com (E. U ¨ lgen), doganh@erciyes.edu.tr (H. Do gan), hakgumus33@yahoo. com (H. Gumus), skumandas@hotmail.com (S. Kumandas), drnbayram@gmail.com (N. Bayram), kaya.bilguvar@yale.edu (K. Bilguvar), okaycaglayan@yahoo.com (A.O. C ¸a glayan). Official Journal of the European Paediatric Neurology Society european journal of paediatric neurology xxx (2015) 1 e4 http://dx.doi.org/10.1016/j.ejpn.2015.06.003 1090-3798/© 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Kac ¸ ar Bayram A, et al., A rare case of congenital fibrosis of extraocular muscle type 1A due to KIF21A mutation with Marcus Gunn jaw-winking phenomenon, European Journal of Paediatric Neurology (2015), http://dx.doi.org/10.1016/ j.ejpn.2015.06.003