Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. The primary objective of this study was to evaluate the prevalence of low femoral and lumbar spine bone mineral density BMD in adults with arthrogryposis multiplex congenita AMC.
Fifty-one patients mean age, Arthrogryposis multiplex congenita AMC is a heterogeneous group of congenital conditions characterized by joint contracture in at least two parts of the body 1. AMC classification can be challenging. The most useful distinction in clinical practice is among i Amyoplasia, a sporadic anterior horn cell disease characterized by selective atrophy or absence of limb girdle muscles and upper and lower limb muscles; ii distal arthrogryposis; and iii nonspecified AMC 2.
The causes of fetal hypokinesia or akinesia leading to the development of AMC are variable and include gene mutation, bacterial or viral infection, teratogenic factors and mechanical restrictions of intrauterine movement 3 , 4. Mechanical loading is an important factor in the regulation of bone growth and metabolism through its involvement in the proliferation and differentiation of osteoblasts 5. Newborns with congenital neuromuscular diseases that restrict fetal movement and decrease mechanical stimulation during intrauterine development, as observed in AMC, develop osteopenia and low bone cortical thickness 6.
Hypomineralization and hypoechogenicity of the long bones in the third trimester of pregnancy were described in a case report 7. Ten percent of newborns with AMC experience long bone fractures during delivery or the perinatal period 8. Patients with AMC have muscle weakness and joint contractures, poor mobility and mechanical arthropathy, which are factors known to increase the risk of falls that can lead to fracture 9 , 10 , Fifty-eight percent of adult patients with AMC report having experienced multiple falls, which is a greater percentage than in the general population Dahan-Oliel et al.
A low BMD may be explained by a lack of mechanical loading from intrauterine development into adulthood. The primary study objective was to evaluate the prevalence of low lumbar spine and hip BMD in a cohort of adults with AMC. The secondary objectives were to assess the prevalence of hydroxyvitamin D OHD deficiency, disorders of calcium and phosphate metabolism, and fractures and to identify factors associated with low BMD in adult patients with AMC.
