1. Department of Medical Genetics, Medical University Varna, Marin Drinov Str 55, 9000 Varna, Bulgaria
2. Laboratory of Medical Genetics, St. Marina Hospital, Hristo Smirnenski Blv 1, 9000 Varna, Bulgaria
3. Laboratory of Clinical Immunology, St. Marina Hospital, Hristo Smirnenski Blv 1, 9000 Varna, Bulgaria
4. Department of Hygiene and Epidemiology, Medical University Varna, Marin Drinov Str 55, 9000 Varna, Bulgaria