Science and Education Publishing American Journal of Medical Case Reports 2 9 2014 09 10 Protein S Deficiency Related Retinal Artery Occlusion in a Pregnant Chinese Woman 175 180 EN Syed Shoeb Ahmad Ophthalmology Department, Queen Elizabeth Hospital, Kota Kinabalu, Malaysia Shuaibah Abdul Ghani Lindfay Laura Lau AJMCR2014294 10.12691/ajmcr-2-9-4 2014 09 01 2014 09 07 2014 09 10 Purpose: To report a case of branch retinal artery occlusion (BRAO) in a pregnant patient of Chinese descent found to have Protein S deficiency. Case report: A 35 year-old apparently healthy, pregnant female of Chinese origin reported in the eye clinic of our hospital with a complaint of sudden appearance of a “shadow” in the periphery of her left eye for the last three days. On examination, she was found to have a BRAO in that eye. A number of laboratory, radiological and systemic examinations were done to find out the cause of the occlusion. However, a deficiency of Protein S was the only abnormality found. So far there have been only a few cases reported concerning this hematological deficiency causing a BRAO. This case report describes the events leading to the diagnosis of this rare condition. Conclusion: In cases of BRAO, especially in young patients it is important to rule out Protein S deficiency which may have life-threatening consequences.