Occlusal traits and longitudinal dental changes in children and adolescents with congenital or childhood onset myotonic dystrophy.

BACKGROUND/OBJECTIVES: This research aimed to study the malocclusions of children and adolescents with myotonic dystrophy type 1 (DM1), in respect to healthy individuals, and trace the occlusal changes that occurred in these individuals during growth. MATERIALS/METHODS: Thirty-six dental casts, from children and adolescents with DM1 living in western and southern Sweden, were compared with a control group of 50 healthy individuals. To identify potential changes in occlusal traits, 26 casts were assessed and followed-up over a median time of 9 years. Independent samples t-tests were used to compare the two groups and their changes over time. Paired samples t-tests tested changes over time within each group (P < 0.05). RESULTS: DM1 patients had a higher prevalence of anterior open bite, posterior crossbite, and Class III malocclusions. When compared to controls, patients presented smaller upper and lower intermolar as well as intercanine widths. In both groups, the individuals revealed longitudinal changes with a decrease in both upper and lower arch lengths and an increase on the palatal vault height. During the follow-up period, the prevalence of malocclusions remained almost the same, only significantly differing regarding the changes that occurred between groups referred to the upper intermolar width, which decreased among DM1 patients. CONCLUSIONS/IMPLICATIONS: In comparison to healthy controls, children and adolescents with DM1 have shown already at an early age a higher prevalence of both anterior open bite and posterior crossbite. These occlusal traits did not change with time apart from the upper narrow intermolar width, which further decreased with time.

Daily activity performance in congenital and childhood forms of myotonic dystrophy type 1: a population-based study.

AIMS: To identify and describe the profile characterizing motor and process skills during daily activity performance in individuals with congenital and childhood forms of myotonic dystrophy type 1 (DM1) and to investigate differences in performance between subgroups. METHOD: Sixty participants (34 males, 26 females, mean age=17y 8mo, SD=6y 0mo, range 5y 8mo-29y 0mo) were divided into severe congenital (n=9), mild congenital (n=20), and childhood (n=31) DM1 subgroups. Daily activity performance was evaluated using a standardized observational instrument: the Assessment of Motor and Process Skills. RESULTS: Deficits in performance were more pronounced in process than motor skills. Performance more than 2 SDs below age-specific norms was seen in 65% of participants for process skills and 33% of participants for motor skills. The cut-off scores indicated a potential need for assistance in daily activities for 79% of participants older than 18 years of age (n=28) due to deficient process skills. INTERPRETATION: Extensive deficits in daily activity performance were found in congenital and childhood forms of DM1, mainly owing to deficient process skills. Such skills impact on the ability to perform daily activities and could explain dependency in individuals with DM1. Process skills should be considered when evaluating daily activity performance. WHAT THIS PAPER ADDS: Young people with myotonic dystrophy type 1 show deficits in motor and process skills when performing daily activities, compared with normative data. Deficits in process skills were more pronounced than deficits in motor skills.

Patient-reported study of the impact of pediatric-onset myotonic dystrophy.

INTRODUCTION: The prevalence and impact of symptoms affecting individuals with pediatric forms of myotonic dystrophy type-1 (DM1) are not well understood. METHODS: Patients from the United States, Canada, and Sweden completed a survey that investigated 20 themes associated with pediatric-onset DM1. Participants reported the prevalence and importance of each theme affecting their lives. Surveys from participants were matched with surveys from their caregivers for additional analysis. RESULTS: The most prevalent symptomatic themes included problems with hands or fingers (79%) and gastrointestinal issues (75%). Problems with urinary/bowel control and gastrointestinal issues were reported to have the greatest impact on patients' lives. Responses from participants and their caregivers had varying levels of agreement among symptomatic themes. DISCUSSION: Many symptoms have meaningful impact on disease burden. The highest levels of agreement between caregivers and individuals with pediatric forms of myotonic dystrophy were found for physical activity themes.

Cognitive and adaptive functioning in congenital and childhood forms of myotonic dystrophy type 1: a longitudinal study.

AIM: To conduct a longitudinal follow-up of the development of global cognitive abilities and adaptive skills in individuals with congenital and childhood forms of myotonic dystrophy type 1 (DM1). METHOD: Fifty-one participants (29 males, 22 females, mean age 19y 5mo, SD 4y 11mo, range 10y 10mo-28y 11mo) were divided into severe congenital (n=16), mild congenital (n=17), and childhood DM1 (n=18) subgroups. The average time between the first and second assessments was 7 years 8 months. Adaptive skills were evaluated using the Vineland Adaptive Behavior Scales and global cognitive functioning using Wechsler scales. RESULTS: There was no statistically significant decline in cognitive abilities and adaptive behaviour. A tendency of decline regarding the level of intellectual disability was found in the congenital DM1 groups but not in the childhood group. In the congenital DM1 groups, the gap in relation to typically developing peers in cognitive and adaptive functioning increased. Predictors of change over time in adaptive skills were age and current level of intellectual disability: individuals with severe intellectual disability and younger individuals deteriorated the most. However, when raw scores were compared, no actual regression in adaptive functioning was found. INTERPRETATION: The participants had not lost any important adaptive skills. Greater cognitive and adaptive development was found in the childhood group than in the congenital groups. WHAT THIS PAPER ADDS: There is no absolute decline in cognitive and adaptive abilities in individuals with congenital and childhood myotonic dystrophy type 1. Pace of development is slow in comparison with normative data. The childhood group tended to show greater cognitive and adaptive development than the congenital groups.

FUNCIONAMIENTO COGNITIVO Y ADAPTATIVO EN LA INFANCIA Y FORMAS CONGÉNITAS DE DISTROFIA MIOTÓNICA TIPO 1: UN ESTUDIO LONGITUDINAL: OBJETIVO: Realizar un seguimiento longitudinal del desarrollo de las capacidades cognitivas globales y las habilidades de adaptación en individuos con formas congénitas e infantiles de distrofia miotónica tipo 1 (DM1). MÉTODO: Cincuenta y un participantes (29 varones, 22 mujeres, edad media 19 y 5 meses, SD 4 años y 11 meses, rango 10 años y 10 meses y 28 años y 11 meses) se dividieron en congénitos graves (n = 16), congénitos leves (n = 17) y DM infantil 1 (n = 18). El tiempo promedio entre la primera y la segunda evaluación fue de 7 años y 8 meses. Las habilidades adaptativas se evaluaron utilizando las escalas de comportamiento adaptativo de Vineland y el funcionamiento cognitivo global utilizando escalas de Wechsler. RESULTADOS: No hubo una disminución estadísticamente significativa en las capacidades cognitivas y el comportamiento adaptativo. Se encontró una tendencia de disminución con respecto al nivel de discapacidad intelectual en los grupos de DM1 congénitos, pero no en el grupo de la infancia. En los grupos de DM1 congénitos, la brecha en relación con los compañeros de desarrollo típico en el funcionamiento cognitivo y adaptativo aumentó. Los factores predictivos del cambio a lo largo del tiempo en las habilidades de adaptación fueron la edad y el nivel actual de discapacidad intelectual: las personas con discapacidad intelectual grave y las personas más jóvenes se deterioraron más. Sin embargo, cuando se compararon las puntuaciones brutas, no se encontró una regresión real en el funcionamiento adaptativo. INTERPRETACIÓN: Los participantes no habían perdido ninguna habilidad adaptativa importante. Se encontró mayor desarrollo cognitivo y adaptativo en el grupo infantil que en los grupos congénitos.

FUNCIONAMENTO COGNITIVO E ADAPTATIVO EM FORMAS CONGÊNITAS INFANTIS DA DISTROFIA MIOTÔNICA TIPO 1: UM ESTUDO LONGITUDINAL: OBJETIVO: Conduzimos um acompanhamento longitudinal do desenvolviemtno de capacidades cognitivas globais e capacidades adaptativas em indivíduos com formas congênitas e da infantis da distrofia miotônica tipo 1 (DM1). MÉTODO: Cinquenta e um participantes (29 do sexo masculino, 22 do sexo feminino, média de idade 19a 5m, DP 4a 11m, variação 10a 10m-28a 11m) foram divididos em DM1 congênita severa (n=16), congênita leve (n=17), e da infância (n=18). O tempo médio entre a primeira e a segunda avaliação foi 7 anos e 8 meses. Capacidades adaptativas foram avaliadas usando as Escalas Vineland de Comportamento Adaptativo, e as escalas Wechsler de funcionamento cognitivo global. RESULTADOS: Não houve declínio estatisticamente significativo nas capacidades cognitivas e comportamento adaptativo. Uma tendência de declínio no nível de incapacidade intelectual foi encontrado nos grupos de DM1congênita, mas não no grupo da infância. Nos grupos com DM1 congênita, a distância em relação aos pares com desenvolvimento típico no funcionamento cognitivo e adaptativo aumentou. Preditores de mudança com o passar do tempo nas habilidades adaptativas foram a idade e o nível atual de incapacidade intelectual: indivíduos com incapacidade intelectual severa e indivíduos mais jovens deterioraram mais. No entanto, quando as pontuações brutas foram comparadas, nenhuma regressão real no funcionamento adaptativo foi encontrada. INTERPRETAÇÃO: Os participantes não perderam nenhuma habilidade adaptativa importante. Maior desenvolvimento cognitivo e adaptativo foi encontrado no grupo da infância comparado aos grupos congênitos.

Speech characteristics in the congenital and childhood-onset forms of myotonic dystrophy type 1.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a slowly progressive multi-systemic disease with an autosomal-dominant inheritance caused by a mutation on chromosome 19 (19q13.3). AIMS: To explore speech characteristics in a group of individuals with the congenital and childhood-onset forms of DM1 in terms of intelligibility, speech-sound production, nasality and compensatory articulation. A further aim was to analyse whether speech characteristics were correlated to subforms of DM1 and if speech outcome could be related to muscle strength. METHODS & PROCEDURES: Fifty native Swedish speakers (7-29 years old) with the congenital and childhood-onset forms of DM1 and 13 healthy controls participated in the study. The intelligibility of spontaneous speech, speech-sound production - single-word and sentence repetition - including percentage consonants correct (PCC) and compensatory articulation, were evaluated by speech-language pathologists from video recordings. A nasometer and lip-force meter were used for objective evaluations of nasality and orofacial strength. OUTCOMES & RESULTS: In severe (n = 9) and mild congenital DM1 (n = 13), all participants had impaired intelligibility to some degree, while this applied to 79% of those with childhood DM1 (n = 28). PCC for bilabials were 53.9% in severe congenital DM1, 57.4% in mild congenital DM1 and 85.3% in childhood DM1; the corresponding results for dentals were 69.3%, 59.2% and 87.3%. Bilabials were most often compensated for with interdental or labiodental articulation. Dentals were substituted with interdental articulation. Velars were seldom affected. The mean nasalance score was high in the study group compared with controls and with normative data and the majority had weak lips. Maximum lip force, as well as the mean nasalance score, correlated significantly with the intelligibility score. CONCLUSIONS & IMPLICATIONS: The deviant production of bilabial consonants, interdental articulation and hypernasal speech are characteristic features of dysarthria in congenital and childhood DM1. Dysarthria is more frequent and more severe in congenital DM1 compared with childhood DM1. Most individuals with congenital DM1 and childhood-onset DM1 will need speech therapy from a young age. For some children with incomprehensible speech or severe neurodevelopmental disorders, alternative and augmentative ways of communication will be part of the treatment.

Parent-reported multi-national study of the impact of congenital and childhood onset myotonic dystrophy.

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.

Healthcare resource utilisation and direct medical cost for individuals with 5q spinal muscular atrophy in Sweden.

BACKGROUND: Spinal muscular atrophy (SMA) is a rare, progressive, neuromuscular disorder. Recent advances in treatment require an updated assessment of burden to inform reimbursement decisions. OBJECTIVES: To quantify healthcare resource utilisation (HCRU) and cost of care for patients with SMA. METHODS: Cohort study of patients with SMA identified in the Swedish National Patient Registry (2007-2018), matched to a reference cohort grouped into four SMA types (1, 2, 3, unspecified adult onset [UAO]). HCRU included inpatient admissions, outpatient visits, procedures, and dispensed medications. Direct medical costs were estimated by multiplying HCRU by respective unit costs. Average annual HCRU and medical costs were modelled for SMA versus reference cohorts to estimate differences attributable to the disease (i.e., average treatment effect estimand). The trajectory of direct costs over time were assessed using synthetic cohorts. RESULTS: We identified 290 SMA patients. Annualised HCRU was higher in SMA patients compared with reference cohorts. Highest risk ratios were observed for inpatient overnight stays for type 1 (risk ratio [RR]: 29.2; 95% confidence interval [CI]: 16.0, 53.5) and type 2 (RR: 23.3; 95% CI: 16.4,33.1). Mean annual direct medical costs per patient for each year since first diagnosis were greatest for type 1 (€114,185 and SMA-attributable: €113,380), type 2 (€61,876 and SMA-attributable: €61,237), type 3 (€45,518 and SMA-attributable: €44,556), and UAO (€4046 and SMA-attributable: €2098). Costs were greatest in the 2-3 years after the first diagnosis for all types. DISCUSSION AND CONCLUSION: The economic burden attributable to SMA is significant. Further research is needed to understand the burden in other European countries and the impact of new treatments.

Behavioural strengths and difficulties in relation to intellectual functions and age in Swedish boys with Duchenne muscular dystrophy.

The aim of this study was to describe behavioral strengths and difficulties in relation to intellectual function and age in boys with DMD. In a cross-sectional design, 70 boys with DMD were tested at 5, 8, 11, and 14 years of age (mean age 10y 5 m). Parental ratings of behavioral strengths and difficulties were studied in relation to age, intellectual function, motor function, and family socioeconomic status (SES). Results show a significant relation between behavioral strengths and difficulties and age with parents rating increasingly more difficulties (slightly higher, higher and very high) from 5 years (11.1%) to 9 years (30.8%) and 11 years (78.9%) of age and then fewer difficulties at 14 years (50%) of age. Working Memory Index (WMI) explained significant variance in SDQ-Total-Score (17.5%) and SDQ-Impact-Score (11.2%). WMI together with upper motor function explained 19.5% variance in SDQ-Hyperactivity and 19.7% in SDQ-Peer-Problems. Age and SES explained an 18.9% variance in SDQ-Emotional-Problems. Age is an important factor when analyzing behavioral strengths and difficulties for boys with DMD. The development of boys with DMD needs to be understood in the context of expected developmental trajectory as well as in the decline of psychical functioning. Our study supports that age, cognition, motor function, and family SES all contribute to how behavioral strengths and difficulties evolves in boys with DMD.

Visual function in congenital and childhood myotonic dystrophy type 1.

OBJECTIVE: To investigate visual function in a group of individuals with congenital and childhood myotonic dystrophy type 1 (DM1), to correlate the results to the size of the cytosine-thymine-guanine (CTG) repeat expansion and the onset form, and to compare the results with those of a control group. DESIGN: Cross-sectional study with age- and gender-matched control groups. PARTICIPANTS AND CONTROLS: Forty-nine individuals with severe and mild congenital and childhood DM1 and controls matched for age and gender. METHODS: The ophthalmologic examination included best-corrected visual acuity (BCVA), refraction, slit-lamp biomicroscopy, indirect ophthalmoscopy, and flash visual evoked potentials (VEPs). MAIN OUTCOME MEASURES: Visual acuity, refractive error, pathology of lens, fundus, and VEP pathologic features. RESULTS: The study shows a higher prevalence of low visual acuity, hyperopia, and astigmatism in the study population compared with the controls. The size of the CTG repeat expansion had an impact on BCVA in all subgroups with lower values in individuals with larger expansion size. In childhood DM1, individuals with high hyperopia and astigmatism had greater CTG repeat expansion size than those without. No true cataract was found. Subtle nonspecific fundus changes were present in addition to VEP pathology. CONCLUSIONS: Children and adolescents with DM1 have a variety of visual function pathologies, and DM1 has an impact on the developing visual system, necessitating early ophthalmologic assessment and follow-up.

Cognition and adaptive skills in myotonic dystrophy type 1: a study of 55 individuals with congenital and childhood forms.

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; r(s)=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 (r(s)=-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 (r(s)=0.95, p<0.01) and childhood DM1 groups (r(s)=0.92, p<0.01). INTERPRETATION: Children and adolescents with DM1 exhibit significant cognitive and adaptive problems.

Consensus-based care recommendations for congenital and childhood-onset myotonic dystrophy type 1.

PURPOSE OF REVIEW: Myotonic dystrophy type 1 is a multisystemic disorder caused by a noncoding triplet repeat. The age of onset is variable across the lifespan, but in its most severe form, the symptoms appear at birth (congenital myotonic dystrophy) or in the pediatric age range (childhood-onset myotonic dystrophy). These children have a range of disabilities that reduce the lifespan and cause significant morbidity. Currently, there are no agreed upon recommendations for caring for these children. RECENT FINDINGS: The Myotonic Dystrophy Foundation recruited 11 international clinicians who are experienced with congenital and childhood-onset myotonic dystrophy to create consensus-based care recommendations. The experts used a 2-step methodology using elements of the single text procedure and nominal group technique. Completion of this process has led to the development of clinical care recommendations for this population. SUMMARY: Children with myotonic dystrophy often require monitoring and interventions to improve the lifespan and quality of life. The resulting recommendations are intended to standardize and improve the care of children with myotonic dystrophy.

Autism spectrum conditions in myotonic dystrophy type 1: a study on 57 individuals with congenital and childhood forms.

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.

Consensus-based care recommendations for adults with myotonic dystrophy type 1.

PURPOSE OF REVIEW: Myotonic 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 FINDINGS: The 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. SUMMARY: The resulting recommendations are intended to help standardize and elevate care for this patient population and reduce variability in clinical trial and study environments.

Long-term follow-up of motor function and muscle strength in the congenital and childhood forms of myotonic dystrophy type 1.

The aims of this study were to explore how motor function and muscle strength change over time in the congenital and childhood forms of myotonic dystrophy type 1, further to investigate whether sex, age, disease severity or size of the mutation could explain these changes. Motor function and isometric muscle strength were evaluated at three occasions during 1999-2013 in 57 patients aged 0.7-28.9 years. Median time between first and last assessment was 11.5 years ranging from 9.6 to 13.3 years. The study shows that motor function improves during the first decade, is most pronounced during the first six years, reaches a plateau during adolescence and starts to deteriorate in the beginning of the second decade. The most predictive variables for change are age (p < 0.0001) and number of CTG-repeat expansions (p = 0.0018). Sex or disease severity grade do not predict changes in motor function. Deterioration of muscle strength is most pronounced in ankle dorsiflexors. Knowledge of development and deterioration of motor function is important for clinical decision making and for planning of interventions. This knowledge can also be of interest for patient recruitment in drug trials, since treatment effect might be easier to evaluate in the stable phases of this progressive disorder.

Oral hygiene aspects in a study of children and young adults with the congenital and childhood forms of myotonic dystrophy type 1.

The primary aim was to study the interaction between oral hygiene, oral care, saliva production, and oral motor function in individuals with myotonic dystrophy type 1 (DM1). A secondary aim was to study how oral hygiene, oral care, and saliva flow rate are affected by gender, age, and subgroup of DM1 in this study population. The study comprised 52 individuals, seven to 29 years of age, divided into two subgroups of DM1, the congenital (N = 24) and childhood-onset forms (N = 28). A combined dental and oral motor examination was performed and the participants or caregivers answered a questionnaire with questions about general health and disabilities, medication, dental care, and oral health. Sixteen individuals with a plaque-, gingivitis-, or calculus-index score of 5-6 were considered to have poor oral hygiene. There were no significant differences between subgroups (age, gender, or form of DM1) in terms of the occurrence of calculus, gingivitis, plaque, or saliva flow rate. The mean value of the unstimulated whole saliva flow rate was 0.7(±0.44) mL/min. An open mouth at rest and oral motor dysfunction were frequent findings. The majority of Swedish children and young adults with the congenital or childhood form of DM1 have fair or poor oral hygiene, with a high occurrence of plaque and gingivitis. As a group, individuals with DM1 and poor oral hygiene have a higher frequency of caries and they report less satisfaction with their oral care at home and the quality of dental care received compared with those with good oral hygiene.

Ocular motor function in relation to gross motor function in congenital and childhood myotonic dystrophy type 1.

PURPOSE: To assess ocular motor function in congenital and childhood myotonic dystrophy type 1 (DM1) and correlate the results with cytosine-thymine-guanine (CTG) repeat size, severity of the disease, myotonia and skeletal muscle function. METHODS: A cross-sectional investigation into strabismus, versions/ductions, saccades, smooth pursuit movements and ptosis was performed on 49 individuals with a confirmed diagnosis of DM1, all diagnosed at <18 years of age and with >40 CTG expansion repeats. The results were correlated with myotonia as well as Hammersmith motor ability scale (HMA). In addition, the ocular results were compared to results from an age and- sex-matched control group. RESULTS: Ocular motor abnormalities were seen in 82%; the most frequent findings were altered conjugate eye movements and 'pseudoptosis' while blepharoptosis was rare. Strabismus was most common in the severe congenital subgroup, with a frequency 14 times higher than in the control group. Positive correlations were seen between CTG repeat size and affected eyelids, and between myotonia and affected eyelids; both these findings were most prominent in the mild congenital group. CTG repeat size was also correlated with version/duction defects, and most obviously in the childhood group. Low HMA scores were associated with high occurrence of strabismus and version/duction defects. CONCLUSION: Abnormalities of ocular motor function are frequently present. CTG repeat size correlates positively with altered versions/ductions and eyelid pathology. Gross motor dysfunction correlates with strabismus and defect versions/ductions, and eyelid pathology indicates involvement of myotonia.

Orofacial dysfunction in children and adolescents with myotonic dystrophy.

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 speech-language 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: muscle involvement in relation to disease type and size of expanded CTG-repeat sequence.

This study aimed to: classify a cohort of children and adolescents with myotonic dystrophy (dystrophia myotonica: DM) into congenital and childhood onset forms; estimate CTG expansion size; and quantify muscle strength, contractures, and motor function in children with DM and compare results with those of controls. Participants were clinically examined, medical records were reviewed, and isometric muscle strength, contractures, and motor function were measured. Participants were: 42 children with DM (18 females, 24 males; mean age 8y 9mo [SD 4y 7mo], range 10mo to 17y) and 42 age- and sex-matched, healthy controls. Children with DM were divided into three groups: severe congenital (n=13), mild congenital (n=15), and childhood (n=14). Children with childhood DM were significantly weaker than controls (wrist and ankle dorsiflexors [p=0.0044, p=0.0044 respectively]; hip abductors and flexors [p=0.0464, p=0.0217]; and knee flexors and extensors: [p=0.0382, p=0.0033]). Children with mild congenital DM were significantly weaker than controls in all assessed muscle groups. Contractures and skeletal deformities were more frequent at time of investigation than at birth, suggesting that foot and spine deformities in particular increase over time. Motor function score was significantly lower for children with DM than for controls. Children with severe congenital DM had the lowest motor function, with correlation between motor function and size of CTG repeat (p=-0.743). Children found jumping, heel standing, and head lifting the most difficult items to perform but few had difficulty walking, running, or stair climbing. DM in children is a heterogeneous disorder with a wide spectrum of muscle involvement, and owing to increased risk of contractures and skeletal deformities, regular follow-ups are recommended.