On the paradoxically high relative prevalence of osteogenesis imperfecta type III in the Black population of South Africa

Abstract

In a survey of Black patients with osteogenesis imperfecta (OI) attending the Baragwanath Hospital, Johannesburg, the severe autosomal recessive OI type III was recognized in 21, of whom 18 lived in the Johannesburg area. By contrast only 5 had the ostensibly common mild autosomal dominant OI type I. The estimated minimum population frequency is 0.6 per hundred thousand for OI type III in this group and 0.1 per hundred thousand for OI type I. These figures are the reverse of those calculated for White Australians, where the ratio between OI type I and III is of the order of 7 to 1. This anomalous situation has important genetic and practical implications.

Osteogenesis imperfecta type 3 in South Africa: Causative mutations in FKBP10

“…[6] The high prevalence of OI-3 in the black population was emphasised when a minimum population RESEARCH frequency of 0.6 per 100 000 was established on a basis of 26 affected persons in 15 families living in the Johannesburg region of SA. [3] In contrast, only five affected individuals in this black African community had AD OI-1, which is common worldwide. An additional 42 children of Shona and Ndebele heritage with OI-3 were identified in Zimbabwe, and by the end of 1987, a total of 75 affected children in 38 families had been documented.…”

“…[3] This condition is characterised by numerous fractures, gross deformity of tubular bones, spinal malalignment and marked impairment of growth. Multiple fractures may be present at birth, but the specific radiological appearances in the newborn have not yet been documented.…”

A new osteogenesis imperfecta with improvement over time maps to 11q

“…OI with autosomal recessive inheritance has been reported in various ethnic groups with high rates of consanguinity: the black population of South Africa [Beighton and Versfeld, 1985], an Irish family [Williams et al, 1989] and the American Indian population . COL1A1 and COL1A2 have been excluded as the OI-causing genes in these populations.…”

Osteogenesis imperfecta in southern Africa: Peter Beighton’s legacy

“…These two papers by PB and colleagues have sustained research interest in pursuing molecular genetics studies in families in whom type 1 collagen mutations have been excluded either by linkage or by molecular DNA sequencing. [9,32] In the second paper, PB and Versfeld noted the paradoxically high frequency of autosomal recessive OI type 3 in a hospital clinic survey of black patients with OI. While studies in hospital patients always run the risk of a major ascertainment bias, this sample is reflected in further studies in the southern African population indicating that autosomal recessive forms of OI are more common than the classic autosomal dominant OI type 1.…”