In Nigeria it is a common disease with an incidence of 1.7 per thousand. In tropical and subtropical climates, its incidence has been reported as between 0.015 percent and 2.0 percent of the population. Up to now only a few cases had been reported in Europe. Ainhum usually affects people between 20 and 50 years. The average age is about thirty-eight. The youngest recorded patient was seven years old. It is more common in men than in women (2:1), and is often familial. History
The first description of ainhum in the West appears to have been provided by English surgeon Robert Clarke, who made a passing reference to "dry gangrene of the little toe" as a common occurrence in the Gold Coast in an 1860 report to the Epidemiological Society of London, but did not recognize it as a distinct entity and believed it to be a consequence of "suppressed yaws". Ainhum was first recognized as a distinct disease and described as such in detail by Brazilian physician Jose Francisco da Silva Lima (1826–1910), in 1867. The name "ainhum" (from the Yoruba ayùn, meaning "to saw" or "to file") was used to refer to the disease by Yoruba speakers in Bahia, Brazil, where Silva Lima practiced.The first histological studies of ainhum were conducted by O. E. H. Wucherer and published in 1872, and the first imaging studies were conducted in 1924. References


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Of the term
Willem Vrolik, a Dutch anatomist who was also curator of the "Museum Vrolikianum", which made him privy to many specimens of bodies having birth defects, coined the term "osteogenesis imperfecta": 683  in his bilingual Latin and Dutch language book on teratology, Illustrations of Human and Mammalian Embryogenesis, first published in 1849.Included is a description of the remains of an infant who had what is now known as perinatally fatal OI type II: 347 : 5  (as verified in a 1998 re-examination of the remains by Baljet et al.). The remains were first given to Vroliks father, who could not make sense of them. Vrolik described poorly mineralized bones, bowed long bones, and fractures in various states of healing. Vrolik correctly determined that what he termed OI in the infant was not caused by secondary rickets, but a congenital abnomality causing primary osteopenia; he theorized this was due to a lack of "intrinsic generative energy". Of its classification
Classification of OI has also evolved as scientific understanding of it has improved. Before the advent of modern genetic testing, OI was classified in two broad groups: osteogenesis imperfecta congenita, and osteogenesis imperfecta tarda, a division first proposed by the German physician E. Looser in 1906. Congenita was used to describe the modern clinical types II, III, and some cases of IV, where upon birth the condition was obvious, either due to bowing of the limbs or due to fractures sustained in utero.