Congenital myotonic dystrophy

Johnson NE, Butterfield R, Berggren K, Hung M, Chen W, DiBella D, Dixon M,

Hayes H, Pucillo E, Bounsanga J, Heatwole C, Campbell C. Disease burden and

functional outcomes in congenital myotonic dystrophy: A cross-sectional study.

Neurology. 2016 Jul 12;87(2):160-7.

Abstract

OBJECTIVE:

Herein, we describe the disease burden and age-related changes of congenital-onset myotonic dystrophy (CDM) in childhood.

METHODS:

Children with CDM and age-matched controls aged 0 to 13 years were enrolled. Participants were divided into cohorts based on the following age groups: 0-2, 3-6, and 7-13 years. Each cohort received age-appropriate evaluations including functional testing, oral facial strength testing, neuropsychological testing, quality-of-life measurements, and ECG. Independent-samples t test or Wilcoxon 2-sample test was used to compare the differences between children with CDM and controls. Probability values less than 0.05 are reported as significant.

RESULTS:

Forty-one participants with CDM and 29 healthy controls were enrolled. The 6-minute walk was significantly different between CDM (258.3 m [SD 176.0]) and control participants (568.2 m [SD 73.2]). The mean lip force strength was significantly different in CDM (2.1 N [SD 2.8)] compared to control participants (17.8 N [SD 7.6]). In participants with CDM, the mean IQ (65.8; SD 18.4) was 3 SDs below the mean compared to standardized norms. Measurements of grip strength, sleep quality, and quality of life were also significantly different. Strength measures (oral facial strength, grip strength, and 6-minute walk) correlated with each other but not with participant IQ.

CONCLUSIONS:

This work identifies important phenotypes associated with CDM during childhood. Several measures of strength and function were significantly different between participants with CDM and controls and may be useful during future therapeutic trials.

Johnson NE, Ekstrom AB, Campbell C, Hung M, Adams HR, Chen W, Luebbe E,

Hilbert J, Moxley RT 3rd, Heatwole CR. Parent-reported multi-national study of

the impact of congenital and childhood onset myotonic dystrophy. Dev Med Child

Neurol. 2016 Jul;58(7):698-705.

Abstract

AIM:

The frequency and impact of symptoms experienced by patients with congenital, childhood, and juvenile-onset myotonic dystrophy (CDM/ChDM/JDM) is not documented. This report identifies symptomatic areas with the greatest disease burden in an international population of patients with early-onset myotonic dystrophy type-1 (DM1).

METHOD:

We distributed surveys to parents of patients with CDM/ChDM/JDM. Patients with CDM/ChDM/JDM were members of the US National Registry of DM1 Patients and Family Members, the Canadian Neuromuscular Disease Registry, or the Swedish Health System. Surveys inquired about 325 symptoms and 20 themes associated with CDM/ChDM/JDM. Parents identified the importance of each symptom and theme to their affected child. The prevalence of each symptom and theme were compared across subgroups of patients. The statistical analysis was performed using Fisher's exact and Kruskal-Wallis tests.

RESULTS:

One hundred and fifty parents returned surveys. The most frequently reported symptomatic themes in children were issues involving communication (81.7%) and problems with hands or fingers (79.6%). Problems with communication and fatigue were the issues that were reported to have the greatest impact on childrens' lives, while 24.1% of children reported cardiac disorders and 15.8% had problems with anesthesia.

INTERPRETATION:

A range of symptoms contribute to the burden of disease faced by children with DM1. Many of these symptoms are under-recognized.