Osteogenesis imperfecta (OI) is a group of connective tissue disorders. It is characterized by fragile bone and low bone mass. OI is clinically and genetically heterogeneous. OI type XI is an autosomal recessive condition which is caused by mutations in the FKBP10 gene. The severity of OI-XI can range from very mild forms without fractures to intrauterine fractures and perinatal lethality. The onset of fractures in affecteds can happen between 4 to 18 months of age. Other symptoms include, but are not limited to, short stature, triangular face, joint laxity, scoliosis, bowed extremities, hearing loss and blue sclera.
Diagnosis can be established by skeletal survey, bone densitometry tests, clinical examination, biochemical testing for serum alkaline phosphatase, which is elevated in these patients, and molecular genetic testing. Multidisciplinary management should be available for such patients.
Shaheen et al. (2011) described two Saudi Arabian families with a phenotype that varied between isolated Osteogenesis Imperfecta and Bruck Syndrome. Parents in both families were consanguineous. The two affected sisters in family 1 had skeletal deformities, short stature and delayed development. Mental development was normal in both. Examination of heart, lung abdomen and central nervous system was unremarkable. Pamidronate was given to the second sister at the age of 5-years, and she showed a significant improvement, as she was described as fracture-free for 4 years. The affected children from the second family are cousins for patients in family 1. The index case in family 2 is a 17-year- old boy. He developed the first fracture during difficult labor. He had frequent fractures (3 per year), never walked and developed scoliosis. His brother developed fracture at age of 3-years and improved when pamidronate was administered. Shaheen et al., (2011) identified two distinct mutations in the FKBP10 gene in the two families. The authors affirmed that mutations in FKBP10 gene cause Bruck syndrome and isolated osteogenesis imperfecta.