BACKGROUND : A relatively high frequency of autosomal recessively inherited osteogenesis imperfecta (OI) type 3 (OI-3) is present in the
indigenous black southern African population. Affected persons may be severely handicapped as a result of frequent fractures, progressive
deformity of the tubular bones and spinal malalignment.
OBJECTIVE : To delineate the molecular basis for the condition.
METHODS : Molecular investigations were performed on 91 affected persons from seven diverse ethnolinguistic groups in this population.
RESULTS : Following polymerase chain reaction amplification and direct cycle sequencing, FKBP10 mutations were identified in 45.1%
(41/91) OI-3-affected persons. The homozygous FKBP10 c.831dupC frameshift mutation was confirmed in 35 affected individuals in the
study cohort. Haplotype analysis suggests that this mutation is identical among these OI-3-affected persons by descent, thereby confirming
that they had a common ancestor. Compound heterozygosity of this founder mutation was observed, in combination with three different
deleterious FKBP10 mutations, in six additional persons in the cohort. Four of these individuals had the c.831delC mutation.
CONCLUSION : The burden of the disorder, both in frequency and severity, warrants the establishment of a dedicated service for molecular
diagnostic confirmation and genetic management of persons and families with OI in southern Africa.