Juvenile and Childhood onset DM


There is not much information on the juvenile form of CMD. There is a really good 30 minutes video about the Childhood forms (Red link at end of column). There is also a drug under development by Ionic Pharmaceuticals in Carlsbad, CA. 

BREAKING NEWS ON TREATMENTS: A recent study (Dec 2015) by Japanese and Polish researchers have found that Erythromycin an FDA approved drug might help with the treatment of Myotonic Dystrophy. This drug helped with the treatment of gastric symptoms in patients with myotonic dystrophy in a separate study in 2002. As the Juvenila and Childhood forms will be there for years your doctor may want to consider this treatment. Read more about this potential treatment here.

This information is from a study by:
Steyaert, A Study of the cognitive and psychological profile in 16 Children with congenital or juvenile myotonic dystrophy. Clinical Genetics 1997: 52:135-141

No major problems were noted in these problems at birth. Of the 14 patients with Juvenile CMD, five of them had feeding problems, these early problems were diagnosed with myotonic dystrophy before age 8.  Based on:

Muscular hypotonia
Tiredness after physical exercise
Gastrointestinal problems (constipation and Diarrhea)
Learning Difficulties
The other patients were diagnosed by
Learning Difficulties
Muscular hypotonia
Somnolence (sleepiness)

The mean age for diagnosis is 8.1 years. This is for all of the 14 subjects. So if you are just finding out about this disease for a child it may be that the symptoms need to develop before a clinical diagnosis is made. Learning difficulties are the primary reason most parents seek medical help.

Intelligence Information

Three subjects had mental retardation. Five subjects had borderline intelligence. Five subjects had learning disabilities with IQ between 85-100. Nine of the 14 subjects were in special education programs.

This study included information about the CTG repeats. Steyaert states that the repeat length does not permit the prediction of variation within one diagnostic group but there is a correlation between repeat length and FSIQ (full scale IQ) Thus Steyaert states that roughly the longer the repeat the lower the FSIQ

All 14 were hypotonic and presented facial weakness, myotonia in the face and hands. Delayed fine motor movement was noted in 5 subjects and somnolence (sleepiness) in  4 Most of the Subjects needed long nights rest with over 75% needing 10 or more hours of sleep.

Behavioral Issues

Issues with behavior were noted using the Child Behavior Check List with the main concerns:

  • withdrawal
  • social problems
  • attention problems
  • Depression (2 individuals)
  • Anxiety Disorders
  • Attention Deficit and Hyperactivity Disorder (ADHD)

Clinically 5 individuals were diagnosed with ADHD. However, more showed symptoms of this disorder. The patients showed presented symptoms of mainly relating to attention deficit and impulsivity and very few to hyperactivity.

The prevalence of ADHD in the general population in 1-3%. In this study it was 25% and higher if you consider that the subjects do not show the classical hyperactivity symptoms

The children reporting depression were reported to be teased at school. This aspect deserves special attention of parents and educators. Steps must be taken with other students to educate and instruct them on how to interact with kids with CMyD if this is possible.

A new study from 2012.
Editor Note: DSM IV is the standard classification of mental disorders used by mental health professionals in the United States. It used for patient diagnosis and treatment, and is important for collecting and communicating accurate public health statistics.

type 1

  1. MARIE DOUNIOL1, et. al.

Article first published online: 3 AUG 2012


Cover image for Vol. 54 Issue 9

Developmental Medicine & Child Neurology


Aim  To investigate the psychiatric and cognitive phenotype in young individuals with the childhood form of myotonic dystrophy type 1 (DM1).

Method  Twenty-eight individuals (15 females, 13 males) with childhood DM1 (mean age 17y, SD 4.6, range 7–24y) were assessed using standardized instruments and cognitive testing of general intelligence, visual attention, and visual–spatial construction abilities.

Results  Nineteen patients had repeated a school grade. The mean (SD) Full-scale IQ was 73.6 (17.5) and mean Verbal IQ was significantly higher than the mean Performance IQ: 80.2 (19.22) versus 72.95 (15.58), p=0.01. Fifteen patients had one or more diagnoses on the DSM-IV axis 1, including internalizing disorders (phobia, n=7; mood disorder, n=6; other anxiety disorders, n=5) and attention-deficit–hyperactivity disorder, inattentive subtype (n=8). Twelve out of 22 patients had alexithymia (inability to express feelings with words and to recognize and share emotional states). Cognitive testing found severe impairments in visual attention and visual–spatial construction abilities in four out of 18, and 14 out of 24 patients respectively. No diagnosis was correlated with the transmitting parent’s sex or with cytosine–thymine–guanine (CTG) repeat numbers. Patients with severe visual–spatial construction disabilities had a significantly longer CTG expansion size than those with normal visual–spatial abilities (p=0.04).

Interpretation  Children and adolescents with childhood DM1 have frequent diagnoses on DSM-IV axis 1, with internalizing disorders being the most common type of disorder. They also have borderline low intelligence and frequent impairments in attention and visual–spatial construction abilities.

Here is a great source of information on Childhood onset Myotonic Dystrophy. Please click on the link below. This will take you to the MYOTONIC DYSTROPHY FOUNDATION website and this is a 30 minute Video CLICK HERE ==>. Childhood Onset and Congential DM

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