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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.

This editorial examines a number of vitally important ethical, legal and scientific concerns that have to be addressed to ensure proper and ethical implementation of direct-to-consumer whole-exome sequencing in South Africa. Individuals taking part in this endeavour must be fully informed of the positive and negative sequelae.

Pompe disease (PD) is an autosomal-recessively inherited neuromuscular disease that, if not diagnosed and treated early, can be fatal. It can present from early infancy into adulthood. Due to the lack of acid alpha-glucosidase, there is progressive intracellular accumulation of glycogen. The severity of the disease is determined by age of onset, organ involvement including the degree of severity of muscle involvement, as well as rate of progression. PD is classified into two groups: infantile and late-onset, each having two subgroups. The need for two tests performed by separate methods (screening and confirmatory) is outlined. It is imperative to try to reduce the time to diagnosis and to recognise the possibilities of false-positive results. A multidisciplinary team approach to treatment of affected patients is optimum with, as team leader, a physician who has experience in managing this rare disorder. In this article, we present a brief overview of the disease and provide guidelines for diagnosis and management of this condition in South Africa.