ASTUTE CLINICIAN REPORT Potentially Beneficial Effect of Hydroxychloroquine in a Patient with a Novel Mutation in Protein Kinase Cδ Deficiency Ayca Kiykim 1 & Ismail Ogulur 1 & Safa Baris 1 & Elisabeth Salzer 2 & Elif Karakoc-Aydiner 1 & Ahmet Oguzhan Ozen 1 & Wojciech Garncarz 2 & Tatjana Hirschmugl 2 & Ana Krolo 2 & Ayse Deniz Yucelten 3 & Kaan Boztug 2,4 & Isil B Barlan 1 Received: 18 February 2015 /Accepted: 13 July 2015 # Springer Science+Business Media New York 2015 Abstract Protein kinase C delta (PRKCD) has essential func- tions in controlling B-cell proliferation and apoptosis, devel- opment of B-cell tolerance and NK-cell cytolitic activity. Hu- man PRKCD deficiency was recently identified to be causa- tive for an autoimmune lymphoproliferative syndrome like disorder with significant B-cell proliferation particularly of immature B cells. Here we report a child with a novel mutation in PRKCD gene who presented with CMV infection and an early onset SLE-like disorder which was successfully treated with hydroxychloroquine. Keywords Protein kinase delta c . lupus-like disorders . autoimmunity Introduction Protein kinase C delta deficiency is a newly described immune disregulative syndrome with lupus-like features and increased autoimmunity. PRKCD is essential in B cell homeostasis in humans as shown in PKCδ knockout mice with increased autoimmunity, lymphoproliferation and lupus-like skin rash [1–3]. Clinical manifestations of the so far reported 5 cases include lymphoproliferation and autoimmunity like juvenile systemic lupus erythematosus (SLE) [4–6]. Within this con- text, we report a child with a novel mutation in PRKCD gene with early onset SLE-like skin disease who was successfully controlled by hydroxychloroquine. Case Report A 3.5 year old male was born to a first degree cousin union of healthy parents who was admitted to the neonatal intensive care unit due to respiratory distress for 2 weeks. Past medical history revealed multiple hospital admissions due to recurrent fever at infancy. Only two out of those admissions concluded with myositis and gastroenteritis. In addition, intermittent di- arrhea was remarkable since 6 months of age which sponta- neously resolved in 2 months. However, the etiology remained unknown. At 8 months, he presented with erythematosus skin rash accompanied by fever and thrombocytopenia. Physical examination at admission revealed partial alopecia, a hyper- pigmented skin rash predominantly in sun-exposed areas, cer- vical lymphadenomegaly, hepatosplenomegaly and mild hy- potonia (Fig. 1a). PCR-based molecular analysis revealed a CMV infection which had been successfully treated with gancyclovir and intravenous gammaglobulins (IVIG), re- lapsed a year later. Electronic supplementary material The online version of this article (doi:10.1007/s10875-015-0178-9) contains supplementary material, which is available to authorized users. * Ayca Kiykim dr_gora@yahoo.com 1 Pediatric Allergy and Immunology, Marmara University Pendik Training and Research Hospital, Mimar Sinan Cad. No: 41, 34890 Istanbul, Turkey 2 CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria 3 Department of Dermatology, Marmara University Pendik Training and Research Hospital, Istanbul, Turkey 4 Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria J Clin Immunol DOI 10.1007/s10875-015-0178-9