Prevalence of Symptomatic Charcot-Marie-Tooth Disease in Iceland: A Study of a Well-Defined Population

Abstract

Background/Aim: To determine the prevalence and clinical spectrum of Charcot-Marie-Tooth disease (CMT) in Iceland. Methods: We identified all individuals with symptomatic CMT, based on information from all practicing neurologists, both neurophysiology laboratories and the only neurology department in the country. The diagnosis was based on clinical features and neurophysiological testing. DNA testing was regarded as confirmatory. Results: We identified 37 individuals in 18 families, which were not linked by identifying 5 generations of ancestors. The point prevalence (January 1, 2007) for all CMT subtypes in Iceland was 12.0/10⁵, 10.1/10⁵ for CMT1 and 2.0/10⁵ for CMT2. The clinical features include lower limb weakness (95%), impaired gait (68%), decreased or absent deep tendon reflexes (86%), pes cavus (70%) and hammer toes (46%). Clinical symptoms were similar for the 2 main CMT subtypes. Conclusion: We report the prevalence and clinical spectrum of CMT, which is comparable to the results of other prevalence studies, in a well-defined, total population sample.

Epidemiologic Study of Charcot-Marie-Tooth Disease: A Systematic Review

“…This presents a problem in identifying cases of CMT, and most prevalence studies have included a number of individuals with few or no symptoms that were only discovered when seemingly unaffected family members were studied. This may explain the somewhat higher prevalence found in some studies [21]. …”

“…However, in relation to diagnostic methods used in studies, neurophysiological findings and family history with multiple affected individuals can further support the diagnosis of CMT, which is the most common inherited neuropathy [20]. The systematic screening of multiple close relatives is important [21,22]. …”

“…According to Gudmundsson et al [21], there have recently been major advances in understanding the genetics of CMT. Genetic testing is helpful in subdividing CMT, but this is not a prerequisite for the diagnosis of CMT.…”

“…Gudmundsson et al [21] also reported a high prevalence of CMT in Iceland (12/100,000 population), and improved methods were discussed when comparing another Icelandic study performed in the 1960s, with a reported CMT prevalence of 1.6/100,000.…”

Molecular Epidemiology of Charcot-Marie-Tooth Disease in Northern Ostrobothnia, Finland: A Population-Based Study

“…A recent systematic review on the epidemiology of CMT identified 103 potentially relevant studies, but only 12 studies met the inclusion criteria and 10 studies reported on CMT prevalence [20]. Indeed, population-based studies on the epidemiology of inherited polyneuropathies are quite few [14,21,22,23] and many of them preceded the era of modern molecular diagnostics [24,25]. Instead, there are more studies describing the frequency of CMT and its subtypes in clinical series [6,26,27,28,29] including one figure that is based on unpublished data from Finland [30,31].…”