Predictors of prognosis in type 1 myotonic dystrophy (DM1): longitudinal 18-years experience from a single center

Survival in myotonic dystrophy type 1: a long time follow up-study with special reference to gastrointestinal symptoms

Background

Myotonic dystrophy type 1 (DM1) is a monogenetic disease affecting many organs. Gastrointestinal symptoms are prevalent and of considerable consequences for affected individuals. The life expectancy is shortened and the objective of the study is to evaluate if gastrointestinal symptoms can predict the outcome of the disease.

Method

Fifty-one patients with DM1 were interviewed regarding symptoms from the gastrointestinal tract in the mid-1990s. Survival of all patients was evaluated in 2023 and the impact of symptoms on survival was assessed.

Results

At the beginning of the study, the mean age was 35.9 years, (median 37.0, 9-63). At the end of the study 47 out of the 51 patients were deceased at a mean age of 53.7 years (median 55.7, 32.5-79.0). Patients with the congenital form of DM1 (n = 6) died at an age of 46.0 years (median 45.2, 40.0-53.6). There was no correlation between the gastrointestinal symptoms and survival.

Conclusion

Albeit prevalent and of considerable clinical consequence, gastrointestinal symptoms are not correlated to survival in myotonic dystrophy type 1.

Assessment of Respiratory Function and Need for Noninvasive Ventilation in a Cohort of Patients with Myotonic Dystrophy Type 1 Followed at One Single Expert Center

Introduction

Respiratory insufficiency is one of the main causes of death in myotonic dystrophy type 1 (DM1). Although there is general consensus that these patients have a restrictive ventilatory pattern, hypoventilation, chronic hypercapnia, and sleep disturbances, the prevalence of respiratory disease and indication for the effects of noninvasive ventilation (NIV) need to be further explored.

Objectives

To describe respiratory function and need for NIV at baseline and over time in a cohort of adult patients with DM1.

Methods

A total of 151 adult patients with DM1 were subjected to arterial blood gas analysis, sitting and supine forced vital capacity (FVC), peak cough expiratory flow (PCEF), nocturnal oximetry, and maximal inspiratory pressure and expiratory pressure (MIP/PEP).

Results

On first assessment, 84 of 151 had normal respiratory function (median age: 38 years, median BMI: 23.9, and median disease duration: 11 years); 67 received an indication to use NIV (median age: 49 years, median BMI: 25,8, and median disease duration: 14 years). After a median time of 3.85 years, 43 patients were lost to follow-up; 9 of 84 required NIV; only 17 of 67 with the new NIV prescription were adherent.

Conclusions

We provide additional data on the natural history of respiratory function decline and treatment adherence in a relatively large cohort of well-characterized patients with DM1. A high proportion (28%) was lost to follow-up. A minority (11%) required NIV, and only 25% were treatment adherent, irrespective of specific demographics and respiratory features. Our results also confirm previous findings, showing that age, disease duration, and higher BMIs are predisposing factors for respiratory impairment.

Brain Pathogenesis and Potential Therapeutic Strategies in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy that affects multiple systems including the muscle and heart. The mutant CTG expansion at the 3'-UTR of the DMPK gene causes the expression of toxic RNA that aggregate as nuclear foci. The foci then interfere with RNA-binding proteins, affecting hundreds of mis-spliced effector genes, leading to aberrant alternative splicing and loss of effector gene product functions, ultimately resulting in systemic disorders. In recent years, increasing clinical, imaging, and pathological evidence have indicated that DM1, though to a lesser extent, could also be recognized as true brain diseases, with more and more researchers dedicating to develop novel therapeutic tools dealing with it. In this review, we summarize the current advances in the pathogenesis and pathology of central nervous system (CNS) deficits in DM1, intervention measures currently being investigated are also highlighted, aiming to promote novel and cutting-edge therapeutic investigations.