<prompt> Dystrophic gene mutation leads to :Myasthenia gravisMotor neuron diseasePoliomyelitisDuchenne muscular dystrophy  <response>: Answer is D Duchenne Muscular Dystrophy : Duchenne muscular dystrophy is caused by a mutation in the gene responsible far producing dystrophin. Progressive Muscle Dystrophies Type Inherita nce Defective geneProtein Onset age Clinical features Other Organ systems involved Duchenne XR Dystrophin Before 5 years Progressive weakness of girdle muscles Cardiomyopathy Mental impairment Unable to walk after age 12 Progressive kyphoscoliosis Respiratory failure in second or third decade Becker XR Dystrophin Early childhood to adult Progressive weakness of girdle muscles Able to walk after age 15 Cardiomyopathy Respiratory failure may develop by fouh decade Limb -girdle ADAR Several Early childhood to early adult Slow progressive weakness of shoulder and hip girdle muscles Cardiomyopathy Emery- XRAD EmerinLamins Childhood to Elbow contractures humeral Cardiomyopathy Dreifuss AC adult and peroneal weakness Congenital AR Several At bih or within first few month Hypotonia, contractures , delayed milestones Progression to respiratory failure in some, static course in others CNS abnormalities hypomyelination malformation Eye abnormalities Myotonic AD DM1 : Usually second Slowly progressive weakness Cardiac conduction DM 1, DM2 Expansion decade may be of face, shoulder girdle and defects, mental CTG repeat DM2 : infancy if mother foot dorsiflexion Preferential proximal impairments cataracts, frontal baldness, gonadal Expansion CCTG repeat affected DM I only weakness in DM2 atrophy Facioscapu- lohumeral AD Deletion, Distal 4q Before age 20 Slowly progressive weakness of face, shoulder girdle and foot dorsiflexion Deafness, Coats eye disease Oculopharyng eal AD Expansion, poly A-RNA binding protein 5h to 6h decade Slowly progressive weakness of extraocular, pharyngeal and limb muscles 