Association of Initial Maximal Motor Ability With Long-term Functional Outcome in Patients With COL6-Related Dystrophies.

OBJECTIVE: To accurately categorize the phenotypes of individuals with collagen VI-related dystrophies (COL6-RDs) during the first years of life to predict long-term motor function and pulmonary function, to provide phenotype-specific anticipatory care, and to improve clinical trial readiness. METHODS: This retrospective, multicenter, international study analyzed the relationship of long-term motor and pulmonary function with the initial maximal motor ability achieved in individuals with COL6-RD. RESULTS: We studied 119 patients with COL6-RD from Spain (n = 54) and the United States (n = 65). The early maximal motor milestones of ability to rise from the floor unassisted and ability to climb 4 steps without holding onto a railing demonstrated reliability in distinguishing between 3 COL6-RD phenotypic subgroups: (1) Ullrich congenital muscular dystrophy, (2) intermediate COL6-RD, and (3) Bethlem myopathy. Long-term motor function and pulmonary function are strongly correlated with the maximal motor ability achieved during the first years of life. Maximal motor capacity can predict other disease-relevant events such as the age at loss of ambulation and the need for the initiation of nocturnal noninvasive ventilation. CONCLUSION: This work proposes a prospective phenotypic classification for COL6-RDs that will enable an accurate prediction of a patient's COL6-RD phenotype during the first years of life. The ability to establish a patient's COL6-RD phenotypic classification early will enable a more accurate prognosis of future motor and pulmonary function, thus improving anticipatory clinical care, and it will be instrumental in aiding the design of future clinical trials by allowing early stratification of trial cohorts.

Differences in Adipose Tissue and Lean Mass Distribution in Patients with Collagen VI Related Myopathies Are Associated with Disease Severity and Physical Ability.

Mutations in human collagen VI genes cause a spectrum of musculoskeletal conditions in children and adults collectively termed collagen VI-related myopathies (COL6-RM) characterized by a varying degree of muscle weakness and joint contractures and which include Ullrich Congenital Muscular Dystrophy (UCMD) and Bethlem Myopathy (BM). Given that collagen VI is one of the most abundant extracellular matrix proteins in adipose tissue and its emerging role in energy metabolism we hypothesized that collagen VI deficiency might be associated with alterations in adipose tissue distribution and adipokines serum profile. We analyzed body composition by means of dual-energy X-ray absorptiometry in 30 pediatric and adult COL6-RM myopathy patients representing a range of severities (UCMD, intermediate-COL6-RM, and BM). We found a distinctive pattern of regional adipose tissue accumulation which was more evident in children at the most severe end of the spectrum. In particular, the accumulation of fat in the android region was a distinguishing feature of UCMD patients. In parallel, there was a decrease in lean mass compatible with a state of sarcopenia, particularly in ambulant children with an intermediate phenotype. All children and adult patients that were sarcopenic were also obese. These changes were significantly more pronounced in children with collagen VI deficiency than in children with Duchenne Muscular Dystrophy of the same ambulatory status. High molecular weight adiponectin and leptin were significantly increased in sera from children in the intermediate and BM group. Correlation analysis showed that the parameters of fat mass were negatively associated with motor function according to several validated outcome measures. In contrast, lean mass parameters correlated positively with physical performance and quality of life. Leptin and adiponectin circulating levels correlated positively with fat mass parameters and negatively with lean mass and thus may be relevant to the disease pathogenesis and as circulating markers. Taken together our results indicate that COL6-RM are characterized by specific changes in total fat mass and distribution which associate with disease severity, motor function, and quality of life and which are clinically meaningful and thus should be taken into consideration in the management of these patients.

[Fractures in spinal muscular atrophy]. / Fracturas en la atrofia muscular espinal.

AIM: To determine the frequency of fractures in patients with spinal muscular atrophy, their mechanism of production, age at appearance and functional repercussions. PATIENTS AND METHODS: Sixty-five patients with spinal muscular atrophy were studied. Cases of fractures diagnosed by means of X-rays were collected and the following parameters were analysed: type of spinal muscular atrophy, gait, age at the time the fracture occurred, mechanism of production, location, treatment applied and functional repercussion. RESULTS: Thirteen patients (20%) presented a total of 20 fractures (four of them presented two or more fractures). The mean age was 6.35 years. The fractures were mostly located in the femur and the mechanism of production was falls in 12 cases and minor traumatic injury in eight. No vertebral fractures were detected. All of them were treated conservatively. The only patient with a fracture who was able to walk stopped walking after immobilisation. CONCLUSIONS: The existence of fractures in these patients interferes with their quality of life and their level of functioning. It is important to prevent them from occurring during management of the patient and by ensuring a correct posture in the wheelchair with the use of restraint systems. Further studies are needed on the loss of bone mineral density in these patients and their possible relationship with fractures.

TITLE: Fracturas en la atrofia muscular espinal.Objetivo. Determinar la frecuencia de fracturas en pacientes con atrofia muscular espinal, mecanismo de produccion, edad de aparicion y repercusion funcional. Pacientes y metodos. Se estudian 65 pacientes con atrofia muscular espinal. Se recogen las fracturas diagnosticadas mediante radiografia y se analizan los siguientes parametros: tipo de atrofia muscular espinal, marcha, edad en el momento de la fractura, mecanismo de produccion, localizacion, tratamiento aplicado y repercusion funcional. Resultados. Presentaron fracturas 13 pacientes (20%), con un total de 20 (cuatro presentaron dos o mas fracturas). La edad media fue de 6,35 años. La localizacion fue en su mayoria en el femur y el mecanismo de produccion, en 12 casos por caidas y en 8 por traumatismo menor. No detectamos ninguna fractura vertebral. Todas se trataron de manera conservadora. El unico paciente ambulante que presento una fractura dejo de caminar despues de la inmovilizacion. Conclusiones. La existencia de fracturas en estos pacientes interfiere en su calidad de vida y en el nivel funcional. Es importante la prevencion de las mismas en el manejo del paciente y vigilando la correcta postura en la silla de ruedas con sistemas de sujecion Deberian emprenderse mas estudios sobre la perdida de densidad mineral osea en estos pacientes y su posible relacion con las fracturas.

[Hammersmith functional rating scale for children with spinal muscular atrophy. Validation of the Spanish version]. / Escala de valoración funcional de Hammersmith para niños con atrofia muscular espinal. Validación de la versión española.

AIMS: This study was conducted with the aim of developing the Spanish version of the Hammersmith functional rating scale for children with spinal muscular atrophy (SMA), to establish the interobserver reliability and to adapt it to Spanish children with SMA types II and III. PATIENTS AND METHODS: We assessed 31 children with a mean age of 4.7 years (range: 2.5-9 years) and they were re-assessed at 3, 6 and 12 months. The children with SMA type II could not walk and the children with SMA type III were able to walk. RESULTS: Interobserver reliability was 95%. The median of the score in the group with SMA type II was 17 (range: 0-34) and in the SMA type III group it was 39 (range: 37-40). The results of the group with SMA type II at 12 months were poorer, although not to a statistically significant extent, which suggested that the disease was getting worse. CONCLUSIONS: The Spanish version presents a high degree of interobserver reliability, is easy to administer in clinical practice and is a good tool for assessing the severity of the disease in patients with SMA, above all in those who are unable to walk.