<unk>  (KBD) is a chronic, endemic type of osteochondropathy<unk>  of the bone) that is mainly distributed from northeastern to southwestern China, including 15 provinces. Tibet currently has the highest incidence rate of KBD in China. Southeast Siberia and North Korea are other affected areas. KBD usually involves children ages 5–15. To date, more than a million individuals have suffered from KBD. The symptoms of KBD include joint pain, morning stiffness in the joints, disturbances of flexion and extension in the elbows, enlarged inter-phalangeal joints, and limited motion in many joints of the body. Death of cartilage cells in the growth plate and articular surface is the basic pathologic feature; this can result in growth retardation and secondary osteoarthrosis. Histological diagnosis of KBD is particularly difficult; clinical and radiological examinations have proved to be the best means for identifying KBD. Little is known about the early stages of KBD before the visible appearance of the<unk>  becomes evident in the destruction of the joints. This<unk>  has been recognized for over 150 years but its cause has not yet been completely defined. Currently, the accepted potential causes of KBD include mycotoxins present in grain, trace mineral deficiency in nutrition, and high levels of fulvic acid in drinking water. Selenium and iodine have been considered the major deficiencies associated with KBD. Mycotoxins produced by fungi can contaminate grain, which may cause KBD because mycotoxins cause the production of free radicals. T-2 is the mycotoxin implicated with KBD, produced by members of several fungal genera. T-2 toxin can cause lesions in hematopoietic, lymphoid, gastrointestinal, and cartilage tissues, especially in physeal cartilage. Fulvic acid present in drinking water damages cartilage cells. Selenium supplementation in selenium deficient areas has been shown to prevent this<unk> . However, selenium supplementation in some areas showed no significant effect, meaning that deficiency of selenium may not be the dominant cause in KBD. Recently a significant association between SNP rs6910140 of COL9A1 and<unk>  was discovered genetically, suggesting a role of COL9A1 in the development of<unk> .
Kashin–Beck disease
Kufor–Rakeb syndrome
Mowat–Wilson syndrome
Zunich–Kaye syndrome
Qazi–Markouizos syndrome
Wilson–Mikity syndrome
Gerstmann–Sträussler–Scheinker syndrome
Scheie syndrome