Abstract :
[en] Aim: Neuromuscular Diseases (NMDs) have undergone considerable technological progress in terms of diagnosis and treatment over the past few years. Despite this, some patients remain undiagnosed and therefore without access to specific treatments. Understanding local epidemiology and diagnostic process is essential to improve diagnostic yield.
Methods: We studied the proportion of each NMD and their associated investigations in the patient population of Neuromuscular Reference Center (NMRC) of Liege, Belgium in 2023. Investigation tools included laboratory testing, muscle biopsy, muscle radiology, single gene sequencing, next generation targeted panel (tNGS), rarely whole exome sequencing (WES), and no whole genome sequencing (WGS).
Results: Of the total of 1084 patients regularly followed-up, more than a third had neuropathies (36.6 %) divided equally between genetic and acquired causes. The second more frequent disorders were muscular dystrophies which represented more than a quarter (27.5 %). Thirdly, motor neuron diseases stood for 11.2 % of the patients. The other NMDs (i.e., myopathies, ataxias, spastic paraplegias, and channelopathies) ranged from 2.1 % to 6.7 %. Total unconfirmed diagnosis accounted for 17.8%, confirmed acquired disorders for 30 % and, genetic disorders for 52.2 %. Among genetic diagnosis, 32.7 % were obtained by tNGS. The remaining 67.3% were determined using other genetic testing methods [i.e., array comparative genomic hybridization (aCGH), multiplex ligation-dependent probe amplification (MLPA), polymerase chain reaction (PCR), southern blotting (SB)].
Discussion: Two third of patients could receive a definitive diagnosis without next generation sequencing- which added 17% of additional diagnosis. The added value of WES and WGS to increase diagnostic yield will need to be evaluated in undiagnosed patients or in replacement of tNGS.
