A 20-year Clinical and Genetic Neuromuscular Cohort Analysis in Lebanon: An International Effort

J Neuromuscul Dis. 2022;9(1):193-210. doi: 10.3233/JND-210652.


Background: Clinical and molecular data on the occurrence and frequency of inherited neuromuscular disorders (NMD) in the Lebanese population is scarce.

Objective: This study aims to provide a retrospective overview of hereditary NMDs based on our clinical consultations in Lebanon.

Methods: Clinical and molecular data of patients referred to a multi-disciplinary consultation for neuromuscular disorders over a 20-year period (1999-2019) was reviewed.

Results: A total of 506 patients were diagnosed with 62 different disorders encompassing 10 classes of NMDs. 103 variants in 49 genes were identified. In this cohort, 81.4% of patients were diagnosed with motor neuron diseases and muscular dystrophies, with almost half of these described with spinal muscular atrophy (SMA) (40.3% of patients). We estimate a high SMA incidence of 1 in 7,500 births in Lebanon. Duchenne and Becker muscular dystrophy were the second most frequently diagnosed NMDs (17% of patients). These disorders were associated with the highest number of variants (39) identified in this study. A highly heterogeneous presentation of Limb Girdle Muscular Dystrophy and Charcot-Marie-Tooth disease was notably identified. The least common disorders (5.5% of patients) involved congenital, metabolic, and mitochondrial myopathies, congenital myasthenic syndromes, and myotonic dystrophies. A review of the literature for selected NMDs in Lebanon is provided.

Conclusions: Our study indicates a high prevalence and underreporting of heterogeneous forms of NMDs in Lebanon- a major challenge with many novel NMD treatments in the pipeline. This report calls for a regional NMD patient registry.

Keywords: CMT; DMD; FSHD; Genetics; LGMD; Lebanon; SMA; neuromuscular.

MeSH terms

  • Adolescent
  • Adult
  • Charcot-Marie-Tooth Disease / epidemiology
  • Charcot-Marie-Tooth Disease / genetics
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Lebanon / epidemiology
  • Male
  • Middle Aged
  • Motor Neuron Disease / epidemiology*
  • Motor Neuron Disease / genetics*
  • Muscular Atrophy, Spinal / epidemiology
  • Muscular Atrophy, Spinal / genetics
  • Muscular Dystrophies / epidemiology*
  • Muscular Dystrophies / genetics*
  • Muscular Dystrophies, Limb-Girdle / epidemiology
  • Muscular Dystrophies, Limb-Girdle / genetics
  • Muscular Dystrophy, Duchenne / epidemiology
  • Muscular Dystrophy, Duchenne / genetics
  • Retrospective Studies
  • Young Adult