Objective To characterise the natural history of Ullrich congenital muscular dystrophy (UCMD).

Patients and methods Questionnaire-based nationwide survey to all 5442 certified paediatric and adult neurologists in Japan was conducted from October 2010 to February 2011. We enrolled the 33 patients (age at assessment, 11±6.6 years) who were reported to have collagen VI deficiency on immunohistochemistry in muscle biopsies. We analysed the development, clinical manifestations, Cobb angle and %vital capacity (%VC) in spirogram.

Results Cobb angle over 30° was noted at age 9.9±5.3 years (n=17). The maximum progression rate was 16.2±10°/year (n=13). %VC was decreased exponentially with age, resulting in severe respiratory dysfunction before pubescence. Scoliosis surgery was performed in 3 patients at ages 5 years, 9 years and 10 years. Postoperative %VC was relatively well maintained in the youngest patient. Non-invasive ventilation was initiated at age 11.2±3.6 years (n=13). Twenty-five (81%) of 31 patients walked independently by age 1.7±0.5 years but lost this ability by age 8.8±2.9 years (n=11). Six patients never walked independently.

Conclusions The natural history of scoliosis, respiratory function and walking ability in UCMD patients were characterised. Although the age of onset varied, scoliosis, as well as restrictive respiratory dysfunction, progressed rapidly within years, once they appeared.