Résumé :
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Communication n° 237 Introduction : In frame deletions of exons encoding the central rod domain of dystrophin have been associated with a highly variable phenotype, including asymptomatic individuals. Cae report - We report on a 4-year-old child suffering from transient episodes of limping at the age of 2 and falls since the age of 3. Clinical examination did not show muscle weakness. CPK levels were increased (1300 UI). The electromyogram was normal. Muscle biopsy showed a rhabdomyolysis without features of muscular dystrophy. Immunolabelling for dystrophin, merosin and dysferlin were normal. The hypothesis of a dystrophinopathy with normal expression of the dystrophin complex was raised. Results : Multiplex PCR of the dystrophin gene showed a deletion of exons 50 and 51. This deletion was in frame, and was predicted to be associated to a Becker type of dystrophinopathy. The use of intragenic markers and quantitative PCR suggested that the deletion was inherited from the mother. This was confirmed by testing the maternal grand-parents that revealed that the asymptomatic 69-year-old grand father was a carrier. Family study showed that three additional healthy males, whose ages ranged from 28 to 55 years, also carried the mutation. In light of these family data, genetic counselling was more reassuring. Cardiac echography of the patient was normal and he became spontaneously asymptomatic. The mutation carrier maternal aunt of the patient was pregnant and decided to continue the pregnancy. Conclusions : This observation emphasize the importance of family data, and especially of testing males from the maternal lineage, in genetic counselling for dystrophinopathies associated with moderate or atypical features.
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