A hospital based epidemiological study of genetically determined muscle disease in south western Norway

Epidemiology and natural history in 101 subjects with FKRP-related limb-girdle muscular dystrophy R9. The Norwegian LGMDR9 cohort study (2020)

We aimed to investigate the epidemiology and natural history of FKRP-related limb-girdle muscular dystrophy R9 (LGMDR9) in Norway. We identified 153 genetically confirmed subjects making the overall prevalence 2.84/100,000, the highest reported figure worldwide. Of the 153 subjects, 134 (88 %) were homozygous for FKRP c.826C>A giving a carrier frequency for this variant of 1/101 in Norway. Clinical questionnaires and patient notes from 101 subjects, including 88 c.826C>A homozygotes, were reviewed, and 43/101 subjects examined clinically. Age of onset in c.826C>A homozygotes demonstrated a bimodal distribution. Female subjects showed an increased cumulative probability of wheelchair dependency and need for ventilatory support. Across the cohort, the need for ventilatory support preceded wheelchair dependency in one third of the cases, usually due to sleep apnea. In c.826C>A homozygotes, occurrence of cardiomyopathy correlated positively with male gender but not with age or disease stage. This study highlights novel gender differences in both loss of ambulation, need for ventilatory support and the development of cardiomyopathy. Our results confirm the need for vigilance in order to detect respiratory insufficiency and cardiac involvement, but indicate that these events affect males and females differently.

Perioperative Care for Patients with Neuromuscular Disorders in the Netherlands –A Questionnaire Study Among Anaesthesiologists, Neurologists and Clinical Geneticists

Background: Patients with neuromuscular disorders are at increased risk of suffering perioperative complications. Current knowledge concerning this topic is based on small retrospective studies and expert opinion. Therefore, an individualized multidisciplinary approach to perioperative anaesthesia planning is invaluable to anticipate difficulties and to optimize outcomes. Objective: To evaluate current practice regarding preoperative counselling and perioperative care of neuromuscular patients, with the aim to facilitate standardization and improvement of perioperative care for neuromuscular patients. Methods: A questionnaire-based cross-sectional, observational study was conducted between July, 1st 2020 and December, 31st, 2020 in Dutch anaesthesia, neurology and clinical genetics departments. Main outcome measures were 1.) frequency of consultation requests for neuromuscular patients prior to surgery, 2.) current practice, educational activities and departmental approach to this topic and 3.) preoperative counselling of neuromuscular patients. Results: A total of 83 departments participated. Consultations for a neuromuscular patient scheduled for anaesthesia were requested from anaesthesia and neurology department only infrequently. Local guidelines concerning perioperative care of neuromuscular patients were available in 36.4% of the participating departments. Quality of specific training for residents and staff anaesthetists/neurologists covering perioperative care of neuromuscular patients was rated as ‘very good’ or ‘good’ by 42.9% . Neuromuscular patients scheduled for surgery were ‘always’ or ‘often’ discussed in multidisciplinary meetings involving anaesthesiologists and neurologists in 20.8% of the participating departments. Conclusion: Perioperative care for neuromuscular patients in the Netherlands is highly variable and might benefit from guidelines, education of health care professionals and multidisciplinary meetings between anaesthesiologists and neurologists on a regular basis.

Intergenerational Influence of Gender and the DM1 Phenotype of the Transmitting Parent in Korean Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is the most common autosomal-dominant disorder caused by the CTG repeat expansion of the DMPK, and it has been categorized into three phenotypes: mild, classic, and congenital DM1. Here, we reviewed the intergenerational influence of gender and phenotype of the transmitting parent on the occurrence of Korean DM1. A total of 44 parent–child pairs matched for the gender of the transmitting parent and the affected child and 29 parent–child pairs matched for the gender and DM1 phenotype of the transmitting parent were reviewed. The CTG repeat size of the DMPK in the affected child was found to be significantly greater when transmitted by a female parent to a female child (DM1-FF) (median, 1309 repeats; range, 400–2083) than when transmitted by a male parent to a male child (650; 160–1030; p = 0.038 and 0.048 using the Tukey HSD and the Bonferroni test) or by a male parent to a female child (480; 94–1140; p = 0.003). The difference in the CTG repeat size of the DMPK between the transmitting parent and the affected child was also lower when transmitted from a male parent with classic DM1 (−235; −280 to 0) compared to when it was transmitted from a female parent with mild DM1 (866; 612–905; p = 0.015 and 0.019) or from a female parent with classic DM1 (DM1-FC) (605; 10–1393; p = 0.005). This study highlights that gender and the DM1 phenotype of the transmitting parent had an impact on the CTG repeat size of the DMPK in the affected child, with greater increases being inherited from the DM1-FF or DM1-FC situations in Korean DM1.

Global prevalence of myotonic dystrophy: an updated systematic review and meta-analysis

INTRODUCTION

Myotonic dystrophy (DM), the most common muscular dystrophy in adults, is a group of autosomal inherited neuromuscular disorders characterized by progressive muscle weakness, myotonia and cardiac conduction abnormalities. Due to the different gene mutations, DM has been subclassified into myotonic dystrophy type 1 (DM1) and type 2 (DM2). However, the prevalence studies on DM and its subtypes are insufficient.

METHODS

The PubMed (1966-2022), MEDLINE (1950-2022), Web of Science (1864-2022) and Cochrane Library (2022) databases were searched for original research articles published in English. The quality of the included studies was assessed by a checklist adapted from STrengthening the Reporting of OBservational studies in Epidemiology (STROBE). To derive the pooled epidemiological prevalence estimates, a meta-analysis was performed using the random effects model. Heterogeneity was assessed using the Cochrane Q statistic and the I2 statistic.

RESULTS

A total of 17 studies were included in the systematic review and meta-analysis. Of the 17 studies evaluated, 14 studies were considered medium quality, two studies were considered high quality and one study was considered low quality. The global prevalence of DM varied widely from 0.37 to 36.29 cases per 100,000. The pooled estimate of the prevalence of DM was 9.99 cases (95% CI: 5.62-15.53) per 100,000. The pooled estimate of the prevalence of DM1 was 9.27 cases (95% CI: 4.73-15.21) per 100,000, ranging from 0.37-36.29 cases per 100,000. The pooled estimate of the prevalence of DM2 was 2.29 cases (95% CI: 0.17-6.53) per 100,000, ranging from 0.00-24.00 cases per 100,000.

CONCLUSION

Our study provided accurate estimates of the prevalence of myotonic dystrophy. The high heterogeneity and the lack of high-quality studies highlight the need to conduct higher quality studies on orphan diseases.

Global prevalence of Duchenne and Becker muscular dystrophy: a systematic review and meta-analysis

Background

A variety of mutations in the largest human gene, dystrophin, cause a spectrum from mild to severe dystrophin-associated muscular dystrophies. Duchenne (DMD) and Becker (BMD) muscular dystrophies are located at the severe end of the spectrum that primarily affects skeletal muscle. Progressive muscle weakness in these purely genetic disorders encourages families with a positive history for genetic counseling to prevent a recurrence, which requires an accurate prevalence of the disorder. Here, we provide a systematic review and meta-analysis to determine the prevalence of DMD and BMD worldwide.

Method

The current systematic review and meta-analysis was carried out using Cochrane seven-step procedure. After determining the research question and inclusion and exclusion criteria, the MagIran, SID, ScienceDirect, WoS, ProQuest, Medline (PubMed), Embase, Cochrane, Scopus, and Google Scholar databases were searched to find relevant studies using defined keywords and all possible keyword combinations using the AND and OR, with no time limit until 2021. The heterogeneity of studies was calculated using the I² test, and the publication bias was investigated using the Begg and Mazumdar rank correlation test. Statistical analysis of data was performed using Comprehensive Meta-Analysis software (version 2).

Results

A total of 25 articles involving 901,598,055 people were included. The global prevalence of muscular dystrophy was estimated at 3.6 per 100,000 people (95 CI 2.8–4.5 per 100,000 people), the largest prevalence in the Americans at 5.1 per 100,000 people (95 CI 3.4–7.8 per 100,000 people). According to the subgroup analysis, the prevalence of DMD and BMD was estimated at 4.8 per 100,000 people (95 CI 3.6–6.3 per 100,000 people) and 1.6 per 100,000 people (95 CI 1.1–2.4 per 100,000 people), respectively.

Conclusion

Knowing the precise prevalence of a genetic disorder helps to more accurately predict the likelihood of preventing its occurrence in families. The global prevalence of DMD and BMD was very high, indicating the urgent need for more attention to prenatal screening and genetic counseling for families with a positive history.

Epidemiology, healthcare resource utilization and healthcare costs for spinal muscular atrophy in Alberta, Canada

AIMS

Spinal muscular atrophy (SMA) is a progressive neuromuscular disease associated with the degeneration of motor neurons in the brainstem and spinal cord. Studies examining the epidemiology and economic impact of SMA are limited in Canada. This study aimed to estimate the epidemiology as well as healthcare resource utilization (HRU) and healthcare costs for children with SMA in Alberta, Canada.

MATERIALS AND METHODS

We conducted a retrospective study using anonymized data from administrative healthcare databases provided by Alberta Health. Data from 1 April 2010 to 31 March 2018, were extracted for patients <18 years of age identified with SMA. Five-year incidence and prevalence were calculated for cases identified between 1 April 2012 and 31 March 2017. HRU and healthcare costs were assessed one year after SMA diagnosis, including hospitalizations, physician visits, ambulatory care visits and long-term care admissions.

RESULTS

The five-year incidence and prevalence of pediatric onset SMA were 1.03 per 100,000 person-years and 9.97 per 100,000 persons, respectively. General practitioner, specialist, and ambulatory care visits were common among children with SMA in the first-year post-diagnosis. The mean (SD) total annual direct cost per patient in the first-year post-diagnosis was $29,774 ($38,407); hospitalizations accounted for 41.7% of these costs ($12,412 [$21,170]), followed by practitioner visits at 32.3% ($9,615 [$13,054]), and ambulatory care visits at 26.0% ($7,746 [$9,988]).

CONCLUSIONS

Children with SMA experience substantial HRU, particularly for hospitalizations and practitioner visits, following diagnosis. Given the high costs of SMA, timely access to effective treatment strategies, such as the novel survival motor neuron (SMN)-restoring treatments recently approved for use, are needed to improve health outcomes and HRU.

The prevalence of hereditary neuromuscular disorders in Northern Norway

AIM

To investigate the point prevalence of hereditary neuromuscular disorders on January 1, 2020 in Northern Norway.

METHODS

From January 1, 1999, until January 1, 2020, we screened medical and genetic hospital records in Northern Norway for hereditary neuromuscular disorders.

RESULTS

We identified 542 patients with a hereditary neuromuscular disorder living in Northern Norway, giving a point prevalence of 111.9/100,000 on January 1, 2020. The prevalence of children (<18 years old) and adults (≥18 years old) were 57.8/100,000 and 125.1/100,000, respectively. Inherited neuropathies had a prevalence of 38.8/100,000. Charcot-Marie-Tooth and hereditary neuropathy with liability to pressure palsies had a prevalence of 29.9/100,000 and 8.3/100,000, respectively. We calculated a prevalence of 3.7/100,000 for spinal muscular atrophies and 2.4/100,000 for Kennedy disease. Inherited myopathies were found in 67.7/100,000. Among these, we registered 13.4/100,000 myotonic dystrophy type 1, 6.8/100,000 myotonic dystrophy type 2, 7.3/100,000 Duchenne muscular dystrophy, 1.6/100,000 Becker muscular dystrophy, 3.7/100,000 facioscapulohumeral muscular dystrophy, 12.8/100,000 limb-girdle muscular dystrophy, 2.5/100,000 hypokalemic periodic paralysis and 11.4/100,000 myotonia congenita.

CONCLUSION

Our total prevalence was higher than previously hypothesized in European population-based studies. The prevalence was especially high for myotonia congenita and limb-girdle muscular dystrophy. The prevalence of Charcot-Marie-Tooth polyneuropathy was higher than in most European studies, but lower than previously reported in epidemiological studies in other regions of Norway.