Jovan Pesovic

Quality of life in patients with myotonic dystrophy type 2

AIM To analyze quality of life (QoL) in a large cohort of myotonic dystrophy type 2 (DM2) patients in comparison to DM1 control group using both generic and disease specific questionnaires. In addition, we intended to identify different factors that might affect QoL of DM2 subjects. PATIENTS AND METHOD 49 DM2 patients were compared with 42 adult-onset DM1 patients. Patients completed SF-36 questionnaire and individualized neuromuscular quality of life questionnaire (INQoL). Following measures were also included: Medical Research Council 0-5 point scale for muscle strength, Addenbrookes cognitive examination revised for cognitive status, Hamilton rating scale for depression, Krupps fatigue severity scale and daytime sleepiness scale (DSS) RESULTS: SF-36 total score and physical composite score did not differ between DM1 and DM2 patients (p>0.05). However, role emotional and mental composite score were better in DM2 (p<0.05). INQoL total score was similar in both groups (p>0.05), although DM2 patients showed less impairment in independence (p<0.05) and body image domains (p<0.01). Regarding symptoms assessed by INQoL, DM2 patients showed less severe complaint of myotonia (p<0.01). Multiple linear regression analysis showed that significant predictors of worse QoL in DM2 patients were older age, worse muscle strength and higher level of fatigue. CONCLUSION QoL reports of DM2 patients with the most severe form of the disease are comparable to those of DM1 patients. Special attention of clinicians should be paid to DM2 patients with older age, more severe muscle weakness and higher level of fatigue since they may be at higher risk to have worse QoL.

Clusters of cognitive impairment among different phenotypes of myotonic dystrophy type 1 and type 2

Neuropsychological examinations in myotonic dystrophy (DM) patients show a great variability of results from a condition of intellectual disability to the subtle cognitive impairments. It is unclear if different clusters of neuropsychological deficits appear in different phenotypes of DM, or if there are patients with no cognitive deficit at all. The aim of this study is to assess cognitive impairments among patients with different phenotypes of DM type 1 (DM1) and type 2 (DM2), and to potentially define cognitive clusters in these disorders. Study comprised 101 DM1 and 46 DM2 adult patients who were genetically confirmed. Patients underwent analysis of five cognitive domains (visuospatial, executive, attention, memory and language). Virtually all DM1 patients had cognitive defect with approximately 2–3 cognitive domains affected. On the other hand, one-third of DM2 patients had completely normal neuropsychological findings, and in other two-thirds approximately 1–2 domains were affected. Cluster analysis showed that in both diseases visuospatial and executive dysfunctions seemed to be the main cognitive defects, while memory and language impairments appeared in more severe phenotypes. Our results showed that a single form of DM1 or DM2 may consist of several cognitive clusters. Understanding of cognitive impairments in DM is very important to follow positive and side effects in ongoing and future clinical trials.

Brain sonography insight into the midbrain in myotonic dystrophy type 2

Introduction: The aim of this study was to analyze transcranial sonography (TCS) findings in genetically confirmed myotonic dystrophy type 2 (DM2) patients. Methods: Forty DM2 patients and 38 gender‐ and age‐matched healthy controls (HCs) underwent TCS through the pre‐auricular acoustic bone window. Results: Substantia nigra hyperechogenicity was found in 20% of DM2 patients compared with 3% of HCs. Brainstem raphe (BR) hypoechogenicity was more common in DM2 patients compared with HCs (56% vs. 10%, P < 0.01), and it was more common in patients with fatigue and excessive daytime sleepiness (P < 0.05). Diameter of the third ventricle was increased in DM2 patients compared with HCs (5.8 ± 1.7 vs. 5.1 ± 1.0 mm, P < 0.05). Conclusions: Finding BR hypoechogenicity might have clinical implication because of the potential response to serotonin‐reuptake inhibitors. TCS revealed alterations in brain structures previously not seen in MRI studies. Muscle Nerve 53: 700–704, 2016

Intellectual Ability in the Duchenne Muscular Dystrophy and Dystrophin Gene Mutation Location

Abstract Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy during childhood. Mutations in dystrophin (DMD) gene are also recognized as a cause of cognitive impairment. We aimed to determine the association between intelligence level and mutation location in DMD genes in Serbian patients with DMD. Forty-one male patients with DMD, aged 3 to 16 years, were recruited at the Clinic for Neurology and Psychiatry for Children and Youth in Belgrade, Serbia. All patients had defined DMD gene deletions or duplications [multiplex ligation- dependent probe amplification (MLPA), polymerase chain reaction (PCR)] and cognitive status assessment (Wechsler Intelligence Scale for Children, Brunet-Lezine scale, Vineland-Doll scale). In 37 patients with an estimated full scale intelligence quotient (FSIQ), six (16.22%) had borderline intelligence (70<FSIQ ≤85), while seven (18.92%) were intellectually impaired (FSIQ <70). The FSIQ was not associated with proximal and distal mutations when boundaries were set at exons 30 and 45. However, FSIQ was statistically significantly associated with mutation location when we assumed their functional consequence on dystrophin isoforms and when mutations in the 5’-untranslated region (5’UTR) of Dp140 (exons 45-50) were assigned to affect only Dp427 and Dp260. Mutations affecting Dp140 and Dp71/Dp40 have been associated with more frequent and more severe cognitive impairment. Finally, the same classification of mutations explained the greater proportion of FSIQ variability associated with cumulative loss of dystrophin isoforms. In conclusion, cumulative loss of dystrophin isoforms increases the risk of intellectual impairment in DMD and characterizing the genotype can define necessity of early cognitive interventions in DMD patients.

Genetic testing of individuals with pre‐senile cataract identifies patients with myotonic dystrophy type 2

V. Rako cevi c-Stojanovi c, S. Peri c, J. Pe sovi c, I. Sen cani c, M. Bo zi c, S. Svikovi c, M. Brku sanin and D. Savi c-Pavi cevi c Neurology Clinic, Clinical Center of Serbia, University of Belgrade School of Medicine, Belgrade, Center for Human Molecular Genetics, University of Belgrade Faculty of Biology, Belgrade, Ophthalmology Department, Clinical Centre Zvezdara, Belgrade, and Ophthalmology Clinic, Clinical Centre of Serbia, Belgrade, Serbia

Molecular genetic and clinical characterization of myotonic dystrophy type 1 patients carrying variant repeats within DMPK expansions

Myotonic dystrophy type 1 (DM1) is caused by a highly unstable expansion of CTG repeats in the DMPK gene. Its huge phenotypic variability cannot be explained solely by the repeat number. Recently, variant repeats within the DMPK expansions have emerged as potential disease modifiers. The frequency of variant expanded alleles was estimated in 242 DM1 patients from 174 Serbian families using repeat-primed PCR (RP-PCR). The patterns of variant repeats were determined by direct sequencing of RP-PCR or PCR products. PCR-based southern blot was performed to get insight into the intergenerational mutational dynamics of variant expanded alleles. All patients carrying variant repeats were clinically re-examined. Variant repeats were observed in eight patients from five families (2.9%). They were detected only at the 3′ end of DMPK expansions. CCG variant repeats were present in seven patients, either as a part of regular runs of CCGCTG hexamer, individual repeats, or CCG blocks. Analyses of three intergenerational transmissions revealed a considerable stability or likely a contraction of variant expanded alleles. Intriguingly, a decrease in age at onset accompanied these transmissions. Overall, patients were characterized by a milder phenotype and/or some atypical symptoms that could be rather clinically suggestive of myotonic dystrophy type 2. In addition, the first case of de novo CTC variant repeat was observed. Variant repeats might explain a part of the phenotypic variability in a small percent of DM1 patients and likely display a stabilizing effect on the meiotic instability of DMPK expanded alleles.

Neuromyelitis Optica in a Patient from Family with both Myotonic Dystrophy Type 1 and 2.

INTRODUCTION The aim of this study was to present a family co-segregating myotonic dystrophy type 1 (DM1) and 2 (DM2), and one member affected with neuromyelitis optica (NMO). CASE REPORT Index case underwent cataract surgery at age 39. Although she had no muscle symptoms, genetic testing revealed a DM2 mutation and a DM1 protomutation. The patient noticed difficulties in climbing stairs at age 47. Clinical examination showed mild muscle weakness, calf hypertrophy, mild myotonia and several multisystem signs. Patients mother had DM1 protomutation and clinically exhibited only cataract. Two probands sisters, one with DM2 mutation and another with DM2 mutation and DM1 protomutation, had a clinical presentation similar to the index case. In addition, the latter also developed NMO. CONCLUSION Our findings suggest that screening for both DM1 and DM2 should be done and a positive result in either gene should not be an indication to stop screening, but to move to the other gene.

Magnetic resonance imaging of leg muscles in patients with myotonic dystrophies

Magnetic resonance imaging (MRI) of muscles has recently become a significant diagnostic procedure in neuromuscular disorders. There is a lack of muscle MRI studies in patients with myotonic dystrophy type 1 (DM1), especially type 2 (DM2). To analyze fatty infiltration of leg muscles, using 3.0 T MRI in patients with genetically confirmed DM1 and DM2 with different disease durations. The study comprised 21 DM1 and 10 DM2 adult patients. Muscle MRI was performed in axial plane of the lower limbs using T1-weighted (T1w) sequence. Six-point scale by Mercuri et al. was used. Fatty infiltration registered in at least one muscle of lower extremities was found in 71% of DM1 and 40% of DM2 patients. In DM1 patients, early involvement of the medial head of gastrocnemius and tibialis anterior muscles was observed with later involvement of other lower leg muscles and of anterior and posterior thigh compartments with relative sparing of the rectus femoris. In DM2, majority of patients had normal MRI findings. Early involvement of lower legs and posterior thighs was found in some patients. Less severe involvement of the medial head of the gastrocnemius compared to other lower leg muscles was also observed, while involvement of proximal muscles was rather diffuse than selective. It seems that both in DM1 and DM2 some muscles may be affected before weakness is clinically noted and vice versa. We described characteristic pattern and way of progression of muscle involvement in DM1 and DM2.

Comparison of temporal and stride characteristics in myotonic dystrophies type 1 and 2 during dual-task walking

OBJECTIVE We analyzed temporal and stride characteristics in patients with myotonic dystrophy type 1 (DM1) and type 2 (DM2) while performing dual mental and motor tasks, and investigated correlations between gait parameters and cognitive impairments. METHOD Dual-task walking was performed by 37 patients (20 DM1 and 17 DM2) and 48 healthy subjects divided into two groups, age- and gender-matched control group for DM1 (HC1) and age- and gender-matched control group for DM2 (HC2). The subjects performed a basic walking task, dual-motor task, dual-mental task, and combined motor and mental task. RESULTS DM1 and DM2 patients differed significantly in temporal and stride characteristics compared to HC. Main differences in DM1 were slower gait and shorter stride length, while both DM1 and DM2 patients had a higher degree of variation of the swing time during dual-task gait, a parameter that reflects posture and balance. Impact of the cognitive dual task on gait pattern changes was also observed. Visuospatial ability correlated with gait changes in DM1, while executive functions had stronger influence in DM2 (p<0.01). Both patient groups had leg muscle weakness. CONCLUSION Gait pattern was impaired in both patient groups concerning temporal and stride characteristics. Dual-task walking paradigm may discover mild initial gait changes and could provide early identification of fall risks and predict possible falls in DM patients.