The current status of medical care for myotonic dystrophy type 1 in the national registry of Japan

Abstract

Introduction/Aims Myotonic dystrophy (DM) is a systemic disease with multiple organ complications, making the standardization of medical care a challenge. We analyzed data from Japan's national registry to clarify the current treatment patterns and demographic features of Japanese DM patients. Methods Using the Japanese National Registry of Muscular Dystrophy (Remudy), we analyzed medical care practice for the multisystemic issues associated with adult DM type 1 patients, excluding congenital DM. Results We included 809 patients with a median age of 44.2 years. Among these patients, 15.8% used ventilators; 31.7% met the index considered at risk for sudden death due to cardiac conduction defects (PR interval over 240 milliseconds or QRS duration over 120 milliseconds) and 2.8% had implanted cardiac devices. Medication for heart failure was prescribed to 9.6% of patients. Overall, 21.2% of patients had abnormal glucose metabolism, of whom 42.9% were treated with oral medications. Among the oral medications, dipeptidyl peptidase‐4 inhibitors were the most common. Cancers were observed in 3.7% of the patients, and endometrial and breast cancers were dominant. Mexiletine was prescribed for myotonia in 1.9% of the patients, and only 1% of the patients received medication for daytime sleepiness. Discussion This study shows difference in treatment patterns for DM1 in Japan compared with other countries, such as lower rates of use of implantable cardiac devices and higher rates of ventilator use. These data may be useful in discussions aimed at standardizing medical care for patients with DM.

Clinical features and genetic spectrum of a multicenter Chinese cohort with myotonic dystrophy type 1

“…Compared to adult DM1 patients with the same age at diagnosis and onset reported in other ethnicities (Table 2 ), Chinese DM1 exhibited fewer CTG repeats (468 ± 139) than those reported in Italy (613 ± 623) [ 15 ], the US (629 ± 386) [ 16 ], and Japan (625 [302, 1047]) [ 17 ]. More importantly, the Chinese patients also presented less multisystem impairments, with lower proportions of cataracts (14–30%) and cardiac defects (35%) reported compared to their Caucasian and Japanese counterparts.…”

“…Lu et al reported lower rates of cataracts (32.4%), cardiac defects (16.2%), and daytime sleepiness (32.4%) in a cohort of 37 Chinese Han DM1 patients [ 7 ]. These three key features are typically common in Caucasians and Japanese DM1, often with a proportion that exceeds 50% [ 17 , 20 ]. The results of our study are generally consistent with those of Lu et al, although we identified a much higher prevalence of daytime sleepiness (70.3%).…”