[Genetics and molecular aspects of dystrophinopathies]

Diagnosis and management of Becker muscular dystrophy: the French guidelines

Becker muscular dystrophy (BMD) is one of the most frequent among neuromuscular diseases, affecting approximately 1 in 18,000 male births. It is linked to a genetic mutation on the X chromosome. In contrast to Duchenne muscular dystrophy, for which improved care and management have changed the prognosis and life expectancy of patients, few guidelines have been published for management of BMD. Many clinicians are inexperienced in managing the complications of this disease. In France, a committee of experts from a wide range of disciplines met in 2019 to establish recommendations, with the goal of improving care of patients with BMD. Here, we present the tools to provide diagnosis of BMD as quickly as possible and for differential diagnoses. Then, we describe the multidisciplinary approach essential for optimum management of BMD. We give recommendations for the initial assessment and follow-up of the neurological, respiratory, cardiac, and orthopedic consequences of males who present with BMD. Finally, we describe the optimal therapeutic management of these complications. We also provide guidance on cardiac management for female carriers.

[Pathogenesis of cognitive disorders in patients with Duchenne muscular dystrophy]

AIM

Clarification of the pathogenesis of cognitive disorders in patients with Duchenne muscular dystrophy in the clinical laboratory and molecular genetic study.

MATERIAL AND METHODS

Thirty-six male patients with Duchenne muscular dystrophy (DMD), aged from 5 to 22 years (mean age 13.7 years), were examined. The control group consisted of 30 healthy people (7-22 years old, mean age 13.8). The clinical, molecular-genetic and laboratory study was conducted. The search for mutations in the dystrophin gene was carried out using multiplex PCR and multiplex ligation-dependent probe amplification. The laboratory study included determination of neurotrophins: brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and ciliary neurotrophic factor (CNTF) using immunoenzyme method in serum.

RESULTS AND CONCLUSION

Severe cognitive impairment was found in 33% of patients with DMD. The distribution of mutations in the DMD gene was not uniform, most often the mutations were found in the region from exon 43 to exon 50. Serum concentration of NGF in patients with DMD was higher than in the control group (2391 pg/ml [1587; 4136] and 553 pg / ml [314; 864], respectively (p<0.001)). In the group of patients with cognitive disorders, there was a decreased concentration of BGF (23 670 [21 700; 30 720] pg/ml (p<0.001)). In patients with BGF concentration less than 31 000 pg/ml, the chances of cognitive disorders were more than 10 times higher (p<0.001, odds ratio OR=12.0, 95% CI [1.9-76.4]). Thus, biochemical mechanisms, such as NGF overexpression and BGF deficiency, are involved in the development of cognitive disorders in patients with DMD.