Osteogenesis Imperfecta

Abstract

| Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation. NATURE REVIEWS | DISEASE PRIMERS VOLUME 3 | ARTICLE NUMBER 17052 | 1 PRIMER © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d .In this Primer, we provide an overview of epidemio logy, genetics and pathophysiology of osteogenesis imperfecta, as well as diagnosis and management. EpidemiologyStudies from Europe and the United States have found a birth prevalence of osteogenesis imperfecta of 0.3-0.7 per 10,000 births 5,6 . These birth cohort analyses reflect moresevere types of osteogenesis imperfecta and do not include moresubtle types that become apparent after birth. A populationbased study that used the Danish National Patient Register found an annual incidence of osteogenesis imperfecta of 1.5 per 10,000 births between 1997 and 2013 (REF. 7). Population surveys in countries with comprehensive medical databases, such as Finland, estimated a prevalence of about 0.5 per 10,000 individ uals 8 , with most having phenotypically milder osteo genesis imperfecta type I and type IV (BOX 1; TABLE 1). Because these birth cohort and population surveys are based on clinical findings and tend to find mutu ally exclusive populations, a reasonable estimate of the incidence of osteogenesis imperfecta is about 1 per 10,000 individuals. Most patients are heterozygous for mutations in COL1A1 or COL1A2. No difference in the prevalence between sexes was reported.Approximately 90% of the 3,000 individuals whose mutations have ...

Novel compound heterozygous variants in the NBAS gene in a child with osteogenesis imperfecta and recurrent acute liver failure

“…Osteogenesis imperfecta (OI) is a group of heterogeneous disease characterised by bone fragility. Studies in the USA suggest a prevalence of 0.3–0.7 per 10 000 births 1. The incidence of OI is estimated to be around 1:15 000 in the general population.…”