Female Duchenne

Abstract

Objective: Duchenne muscular dystrophy (DMD) is a X-linked recessive disease caused by mutations in dystrophin gene and is characterized by progressive muscle degeneration and weakness resulting in poor disease outcome. The disease primarily affects boys. Females are usually only asymptomatic carriers of mutations. Manifesting carriers are those with muscle weakness and/or dilated cardiomyopathy and asymptomatic are considered those with elevated levels of creatine kinase, and/or minor myopathic signs such as myalgia or muscle cramps. Methods: Our patient is a girl in which disease manifested at the age of 13, with muscle weakness and exercise tolerance. During the last two years her problems became more pronounced and we started diagnostic workup under the suspicion of neuromuscular disease. Besides the clear signs of muscle weakness, particularly expressed in the proximal muscles of the lower extremities with positive Gowers sign, she had hypertrophy of the calves. Repeated cardiac examination was normal. Results: We performed initial laboratory testing and observed elevated creatine kinase (CK) 10 times more than the reference value. EMG analysis was of regular neurographic parameters but needle EMG showed pronounced spontaneous outbreak with myopathic pattern. We performed muscle biopsy and histological examination revealed the destructive myopathic process and immunohistochemistry complete absence of dystrophin expression. MLPA revealed a heterozygous deletion of exon 3 and 4 of dystrophin gene. Conclusion: Our female patient most likely has de novo mutation of dystrophin gene that led to expression of symptoms at an earlier age than the average mentioned in literature, symptoms are progressive, and the girl is already difficult to stay ambulatory and we think that she has atypical form of dystrophinopathy with complete absence of dystrophin in muscle biopsy. Nowadays, for our patient besides genetic counseling it is very important to consider medicamentous treatment.