Effects of Physical Training on Bone and Muscle Quality, Muscle Strength, and Motor Coordination in Children With Neurofibromatosis Type 1

Disorders of the Ras pathway have significant phenotypic overlap and include Noonan syndrome, Cardiofaciocutaneous syndrome (CFC syndrome), Legius syndrome, Costello syndrome and neurofibromatosis type 1 (NF1). NF1 is one of the most common genetic disorders presenting in childhood with an incidence of 1/3000. NF1 is associated with skeletal abnormalities such as short stature, scoliosis, and long bone fracture with non-union. We recently reported that children with NF1 have abnormalities of bone and muscle architecture as evidenced by decreased bone mineral density, decreased bone strength, and low muscle mass, all of which may predispose them to fractures and scoliosis (Stevenson et al., 2005, 2007, 2009). Our preliminary data show that children with NF1 have poor motor coordination and muscle strength, potentially secondary to abnormal neuromotor learning. We hypothesize that poor motor coordination and decreased muscle strength contribute to the osteopenia in NF1. Our objective is to identify effective and non-invasive strategies to improve motor coordination, muscle strength, and bone and muscle architecture in children with disorders of the Ras pathway, in hopes of decreasing fractures and improving physical activity levels. Plyometric physical training consists of quick, high-intensity, weight-bearing movements, and is an encouraging intervention for use in these children.