Myotonic dystrophy type 1 (DM1) is an autosomal dominant disorder, caused by an expansion of a CTG triplet repeat in the DMPK gene. The aims of the present study were to classify a cohort of children with DM1, to describe their neuropsychiatric problems and cognitive level, to estimate the size of the CTG expansion, and to correlate the molecular findings with the neuropsychiatric problems. Fifty-seven children and adolescents (26 females; 31 males) with DM1 (CTG repeats > 40) were included in the study. The following instruments were used: Autism Diagnostic Interview-Revised (ADI-R), 5-15, Griffiths Mental Development Scales, and the Wechsler Scales. Based on age at onset and presenting symptoms, the children were divided into four DM1 groups; severe congenital (n = 19), mild congenital (n = 18), childhood (n = 18), and classical DM1 (n = 2). Forty-nine percent had an autism spectrum disorder (ASD) and autistic disorder was the most common diagnosis present in 35% of the subjects. Eighty-six percent of the individuals with DM1 had mental retardation (MR), most of them moderate or severe MR. ASD was significantly correlated with the DM1 form; the more severe the form of DM1, the higher the frequency of ASD. The frequency of ASD increased with increasing CTG repeat expansions. ASD and/or other neuropsychiatric disorders such as attention deficit hyperactivity disorder, and Tourette's disorder were found in 54% of the total DM1 group. In conclusion, awareness of ASD comorbidity in DM1 is essential. Further studies are warranted to elucidate the molecular etiology causing neurodevelopmental symptoms such as ASD and MR in DM1.

Purpose of reviewMyotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects between 1 in 3,000 and 8,000 individuals globally. No evidence-based guideline exists to inform the care of these patients, and most do not have access to multidisciplinary care centers staffed by experienced professionals, creating a clinical care deficit.Recent findingsThe Myotonic Dystrophy Foundation (MDF) recruited 66 international clinicians experienced in DM1 patient care to develop consensus-based care recommendations. MDF created a 2-step methodology for the project using elements of the Single Text Procedure and the Nominal Group Technique. The process generated a 4-page Quick Reference Guide and a comprehensive, 55-page document that provides clinical care recommendations for 19 discrete body systems and/or care considerations.SummaryThe resulting recommendations are intended to help standardize and elevate care for this patient population and reduce variability in clinical trial and study environments.

Aims  To investigate cognitive abilities and adaptive skills in children and adolescents with myotonic dystrophy type 1 (DM1) and correlate the findings to the cytosine‐thymine‐guanine (CTG) repeat expansion size. Method  Cognitive level was assessed in 55 children and adolescents with DM1 (31 males, 24 females; mean age 12y 1mo, SD 5y 1mo; range 2y 7mo–21y 5mo) divided into the following categories: severe congenital DM1 (n=19), mild congenital DM1 (n=18), and childhood DM1 (n=18). The Griffiths Mental Developmental Scale, the Wechsler Scales, and the Vineland Adaptive Behavior Scales (VABS) for adaptive skills were used for this purpose. Results  Learning disability was found in 95% of the severe congenital group, 83% of the mild congenital group, and 89% of the childhood DM1 group. The more severe the form of DM1, the lower the full‐scale IQ (FSIQ; rs=0.28, p=0.044). The individuals with severe congenital and childhood DM1 had a significantly higher verbal IQ than performance IQ (severe congenital: mean difference 5.7, SD 5.7, p=0.008; childhood DM1: mean difference 9.8, SD 18.0, p=0.038). CTG repeat expansion correlated negatively with FSIQ (rs=−0.63, p<0.006). Almost all participants showed poor results on the VABS. There was a positive relationship between cognitive level and adaptive skills in the mild congenital (rs=0.95, p<0.01) and childhood DM1 groups (rs=0.92, p<0.01). Interpretation  Children and adolescents with DM1 exhibit significant cognitive and adaptive problems.

Myotonic dystrophy (DM) is a neuromuscular disorder caused by an expansion of a CTG repeat sequence on chromosome 19q13. The aim of the present study was to describe the characteristics and prevalence of oral motor dysfunction in a cohort of children and adolescents with DM and to correlate different aspects of oral motor function with the type of DM and sex. Fifty-six individuals with DM (30 males, 26 females; median age 13y 2mo; range 2y 6mo-21y 5mo) were compared with healthy controls. They were divided into four subgroups: severe congenital DM (n=18); mild congenital DM (n=18); childhood DM (n=18); and classical DM (n=2). A speechlanguage pathologist assessed different variables of oral motor function, intelligibility, and lip force. The families used a questionnaire to report on eating difficulties and drooling. All individuals with DM had impaired facial expression. Intelligibility was moderately or severely reduced in 30 patients (60%), excluding six patients without speech. Most had a moderate or severe impairment of lip motility (76.0%), tongue motility (52.2%), and lip force (69.2%), causing deviant production of bilabial and dental consonants. The families reported problems with eating (51.9%) and drooling (37.0%). Oral motor dysfunction was most prominent in congenital DM, and males were more affected than females.Myotonic dystrophy (DM) is a slowly progressive neuromuscular disorder with autosomal dominant inheritance. It is caused by an expansion of a CTG repeat sequence (trinucleotide expansion) on chromosome 19q13. The number of CTG repeats correlates broadly with the overall severity of the disease, but the correlation between the size of the CTG repeat sequence and individual clinical manifestations still needs to be elucidated. 1 DM can be congenital and can appear in childhood or later in life (adult or classical type). The cardinal symptoms are weak muscles, especially in the face, neck, hands, and feet, but smooth muscles are also affected. 2 Myotonia is a common feature in adults with DM but this can also be seen in children. [2][3][4][5] Most individuals with the congenital or childhood type have learning disability* and there are an increased number of children and adolescents with DM who have a neuropsychiatric disorder in comparison with the prevalence in the general population. [4][5][6][7] Newborn infants with the congenital form of DM generally have profound difficulties with sucking and breathing because of neonatal hypotonia. Polyhydramnios during pregnancy, caused by poor fetal swallowing, is often noted. 2,4,5 Adults with DM commonly develop flaccid dysarthria with indistinct articulation and hypernasal speech caused by velopharyngeal impairment. [8][9][10][11] The speech characteristics of children and adolescents with DM have not been described previously in any detail. Although orofacial weakness is a characteristic symptom in congenital and childhood DM, 2,4,5 research into the consequences for feeding in infancy, chewing, swallowing, and speech is very limited. Different as...