A multi-source approach to determine SMA incidence and research ready population
Spinal muscular atrophy (SMA) is a progressive muscular disorder caused by mutations in the SMN1 gene. Since little studies have been performed into its epidemiology, a study was performed using multi-resources.
Firstly the incidence (proportion of newborns with SMA) was determined by questioning genetic laboratories in different countries about the number of positive SMN1 diagnoses from 2011 to 2015. This lead to enough response in 18 countries within whole Europe, where an incidence between ~1 in 3900 to16,000 newborns per year was found.
Secondly the prevalence (number of patients alive at a certain time point compared to the total population) of the number of patients really known, and thereby ready for research and clinical trials, was investigated by enquiring the CTSR (on 15 Dec 2015) and the patient registries (on 1 Sept 2015). The CTSR retrieved data from 42 countries and the patient registries from 29 countries (26 registries). This revealed large differences between countries in the relative amount of patients known, whereby by far the largest amount of registered patients lived in Europe. In general the trial ready population was around two to five times lower than expected prevalence.
Mapping the differences in care for 5000 Spinal Muscular Atrophy patients, a survey of 24 national registries in North America, Australasia and Europe.
Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder characterised by degeneration of motor neurons and progressive muscle weakness. It is caused by homozygous deletions in the survival motor neuron gene (SMN1) on chromosome 5.
SMA shows a wide range of clinical severity, with SMA type I patients often dying before two years of age whereas type III patients experience less severe clinical manifestations and can have a normal life span. Here we describe the design, set-up and utilisation of the TREAT-NMD national SMA patient registries characterized by a small, but fully standardized set of registry items and by genetic confirmation in all patients. We analyse a selection of clinical items from the SMA registries in order to provide a snapshot of the clinical data stratified by SMA subtype, and compare these results with published recommendations on standards of care.
Our study included 5068 SMA patients in 25 countries. 615 patients were ventilated, either invasively (178) or non-invasively (437), 439 received tube feeding and 455 had had scoliosis surgery. Some of these interventions were not available to patients in all countries, but differences were also noted among high income countries with comparable wealth and health care system. This study provides the basis for further research, such as quality of life in ventilated SMA patients, and will inform clinical trial planning.