The Belgian neuromuscular diseases registry (BNMDR) was established in 2008, and agreements exist between the National Institute for Health and Disability Insurance (NIHDI), the 7 Belgian neuromuscular reference centers (NMRC) and Sciensano. The project is funded by NIHDI and managed by Sciensano in collaboration with the NMRC. The main objectives of the BNMDR are:
 — Enable epidemiological research in the field of neuromuscular diseases (NMD);
 — Support and promote the quality of care in the NMRC;
 — Provide information to the public health authorities for health care planning in Belgium;
 — Facilitate patient recruitment for clinical trials.
; In 2019, a second (sub)registry dedicated to patients with 5q spinal muscular atrophy (BNMDR-SMA) was launched. In addition to the goals mentioned above, the BNMDR-SMA aims to:
 — Monitor the effectiveness of interventions and new treatments;
 — Support the procedures of market access and treatment reimbursement.
; The BNMDR annually collects data from patients diagnosed with NMD, living in Belgium and who signed an informed consent form. Data are entered by their treating physician of the NMRC. For most NMD, basic data is registered, such as age, sex, place of residence, living status, diagnosis and functional status. For two diseases, Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), an extended dataset is collected in collaboration with the international network TREAT-NMD. The results of the 2018 to 2021 BNMDR data collections, excluding patients with SMA, can be found in chapters 3 and 4. Chapter 5 focuses on the data of patients with DMD. The data of patients with SMA is reported in chapter 6, which is dedicated to the results of the new BNMDR-SMA registry.
; Since the beginning, 55 630 registrations were entered to the BNMDR (i.e. without SMA), coming from 11 380 unique patients with NMD. The total number of registrations was 5 748 in 2018, 5 852 in 2019, 4 569 in 2020 and 5 107 in 2021. The drop in 2020, from which we are still recovering, is attributed to the reduced number of consultations during the COVID-19 pandemic. Based on these numbers, the estimated prevalence of NMD in Belgium ranges between 39,67 and 52,17 per 100 000 population. The number of newly registered patients per year ranged from 711 to 819. Patients’ enrollment remains better in the north of the country than in the south. This difference is most likely to be related to the geographical location of the NMRC. We keep advocating for the recognition of another NMRC in the south of Belgium or putting in place a satellite service from an existing NMRC in that area.
; The NMD population is a heterogeneous group. The characteristics of the patients registered in the BNMDR between 2018 and 2021 are quite stable. In 2021, patients were ranging in age between 0 and 98,2 years (mean age ± SD: 45,3 years ± 21,41). The male to female ratio was 1,2. The 10 most prevalent diseases were hereditary motor and sensory neuropathy (HMSN), amyotrophic lateral sclerosis (ALS), myotonic dystrophy type 1 (DM1), hereditary spastic paraplegia (HSP), chronic inflammatory demyelinating polyneuropathy (CIDP), Duchenne muscular dystrophy (DMD), limb girdle muscular dystrophy (LGMD), facioscapulohumeral dystrophy (FSHD), spinocerebellar ataxias (SCA) and mitochondrial myopathy (MM). Those 10 diseases are analyzed in detail in chapter 4. It should be noted that, compared to previous reports, postpolio syndrome disappeared from the list between 2019 and 2020. Over the past years, we observed that the group of patients diagnosed with postpolio syndrome was no longer increasing due, most likely, to the effectiveness of the polio vaccination program in Belgium. In addition, we cannot exclude that the reduced number of consultations during the COVID-19 pandemic might have contributed to this finding. The proportion of patients who received a final diagnosis gradually increased to 88,5% in 2021. Regarding the stage of the disease, the vast majority of patients were ambulant 81,1% and 13,8% were wheelchair-bound; 4,6% needed ventilation support, of which about one third suffered from DMD and another third from ALS. Over the 2018-2021 period, 610 deaths (i.e. 2,9% of the total population) were reported, with almost two third being diagnosed with ALS.
; The annual number of patients with dystrophinopathy between 2018 and 2021 ranged from 363 to 425. The average prevalence of DMD and Becker muscular dystrophy (BMD) in Belgium for this period was estimated at 4,7 and 1,8 per 100 000 males, respectively. Since the start of the BNMDR, 643 unique patients with dystrophinopathy were registered. One hundred and six were reported as deceased, and 66 are considered lost to follow-up, thus leaving 471 active unique patients. They are 285 patients with DMD, 139 with BMD, 43 manifesting female carriers (MFC) and 4 non-manifesting female carriers (NMFC). The median age falls within the 15-19 years category for patients with DMD, 30-34 years category for patients with BMD and 45-49 years category for female carriers. The majority of the active unique patients (59%) are ambulant. In the DMD group, 36% lost ambulation compared to 14% and 0% in BMD and female carriers, respectively. While 21% of patients with DMD use ventilation, ventilation support is rarely needed in patients with BMD and non-occurring in patients with MFC. The median age at loss of ambulation is between 10 and 14 years for patients with DMD and between 30 and 34 years for patients with BMD. It seems that patients currently under corticosteroids lose ambulation later than those who previously or never received corticosteroids. Indeed, loss of ambulation can be delayed with corticosteroid therapy, which is considered standard of care in DMD. In the unique active BNMDR population, corticosteroids appear to be mainly used in the patients with DMD, with 63% being currently treated and 7% previously. Over the past two decades, several novel therapeutic approaches have been developed to improve patient quality of life and even to treat the underlying cause of the disease. These approaches can be broadly divided into those targeting the restoration of dystrophin production and those trying to reduce the secondary consequences of dystrophin deficiency. In Belgium, most of these treatments are only available through clinical trials. The proportion of unique active patients who participated currently or previously in a clinical trial is 7% and 11%, respectively.
; The annual number of patients registered in the BNMDR-SMA between 2018 and 2021 ranged from 217 to 243, which resulted in an average prevalence estimate of 2,0 per 100 000 population. Contrary to the general trend, the prevalence is higher in the south of Belgium than in the north. A possible explanation lies in the SMA newborn screening (NBS) program piloted in March 2018 in Wallonia which was not implemented in Flanders until December 2022. Since its set-up in 2019, a total of 272 unique patients have been entered in the BNMDR-SMA registry. They are 132 males (48,5%) and 140 females (51,5%), ranging in age between <1 year and 79 years. Their average age is 23,6 years ± 18.1. Nine patients (3,3%) were reported as deceased, and 15 (6,3%) are considered to be lost to follow-up. Among the 272 unique patients with SMA, 12,9% are type I, 39,3% type II, 41,2% type III and 2,9% are type IV. For SMA, three disease modifying therapies (DMT) are available in clinical setting at the moment, i.e. Spinraza®, Zolgensma® and Evrysdi®. How the arrival of DMT impacted the Belgian SMA population is reported in chapter 6. The proportion of patients currently treated by a DMT has continuously increased from 49,3% in 2018 to 80,2% in 2021. Regarding stage of disease, the proportion of ambulant patients slightly increased from 17,5% to 21%. Reversely, the proportion of wheelchair dependent patients decreased from 49,3% to 45,3%. The percentage of patients using ventilation remained stable around 20,8%. Similarly, ‘walking’ as best motor function achieved increased from 44,2% to 47,7%, while ‘sitting’ decreased from 49,3% to 46,1%. In addition to ventilation support, patients with severe types of SMA often need a gastric or nasal feeding tube. The proportion of patients currently having a feeding tube remaind stable around 12,1%. Consistent with an aging population, more patients are diagnosed with scoliosis, going from 61,8% in 2018 to 65,4% in 2021. However, less patients with a scoliosis diagnosis underwent scoliosis surgery, i.e. 61,2% in 2018 compared to 56,6% in 2021. Overall, it seems that DMT have a positive impact on the Belgian SMA population.
; The last chapter of the report describes the patient coverage by the different NMRC, specifically towards the inclusion in the NMD convention and the geographical distribution. These results reveal a clear reduction in the number of patients registered outside convention, most probably related to the increased number of patients included in the convention and the related workload. Geographical coverage graphs clearly show the impact of the lower number of NMRC in the south of the country, namely that patients in the south need to travel further to receive specialised care. We also see that patients from the south have a larger spread over the country. In both Wallonia and Flanders, patients do not always seem to choose for the closest centre.