University of Tehran Press Journal of Veterinary Research 2008-2525 81 1 2026 03 21 Occurrence of Osteopetrosis in an Adult White Leghorn Rooster: A Case Report Occurrence of Osteopetrosis in an Adult White Leghorn Rooster: A Case Report 73 77 105938 10.22059/jvr.2025.395703.3514 FA Mohammad Javad Gharagozlou Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Anahita Gharagozlou Graduated from the Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Fatemeh Moradalian Graduated from the Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Hamid Nafe Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran 0009-0006-1982-7827 Alireza Vajhi Department of Surgery and Radiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Farzin Bengar Graduated from the Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Journal Article 2025 09 29 Osteopetrosis, or “marble bone disease”, is a rare condition that causes bones to grow abnormally and become overly dense. Genetic disorders and/or viral infection contribute to the development of this bone disease. Osteopetrosis can result in a defect in the formation or activity of osteoclasts or an overgrowth of osteoblasts and osteocytes. Osteopetrosis has been reported in humans and different animals, including cows, dogs, cats, rabbits, mice, and birds. This study reports a case of osteopetrosis in a white leghorn rooster.<br />The case was an 18-20-week-old white Leghorn rooster with clinical manifestations of relative anemia in unfeathered regions, walking with a stilted gait, and a “boot-like” appearance of tarsal and metatarsal bones.<br />Bone lesions in macroscopic pathology observations and bilateral radiological images were symmetrical, with bone tissue growth inclined towards the center and a spindle-shaped appearance in some long bones. In addition, due to the growth of bone tissue towards the center, the cavity and bone marrow space were small or completely obliterated, which could explain the anemia caused by osteopetrosis.<br />Based on the history of clinical manifestations, macroscopic and radiological findings, advanced osteopetrosis was diagnosed in an adult white leghorn rooster. Osteopetrosis, or “marble bone disease”, is a rare condition that causes bones to grow abnormally and become overly dense. Genetic disorders and/or viral infection contribute to the development of this bone disease. Osteopetrosis can result in a defect in the formation or activity of osteoclasts or an overgrowth of osteoblasts and osteocytes. Osteopetrosis has been reported in humans and different animals, including cows, dogs, cats, rabbits, mice, and birds. This study reports a case of osteopetrosis in a white leghorn rooster.<br />The case was an 18-20-week-old white Leghorn rooster with clinical manifestations of relative anemia in unfeathered regions, walking with a stilted gait, and a “boot-like” appearance of tarsal and metatarsal bones.<br />Bone lesions in macroscopic pathology observations and bilateral radiological images were symmetrical, with bone tissue growth inclined towards the center and a spindle-shaped appearance in some long bones. In addition, due to the growth of bone tissue towards the center, the cavity and bone marrow space were small or completely obliterated, which could explain the anemia caused by osteopetrosis.<br />Based on the history of clinical manifestations, macroscopic and radiological findings, advanced osteopetrosis was diagnosed in an adult white leghorn rooster. https://jvr.ut.ac.ir/article_105938_12b7af7f33babcb03c9a8bdf80f85ab2.pdf