There is a congenital syndrome in the miniature dachshund, which resolves with age. The weakness may be progressive, and presence of megaesophagus will predispose to aspiration pneumonia. However, desensitization to the drug occurs over time. If there is a deficiency of AChRs and not complete absence, anticholinesterase therapy may be effective. Treatment response depends upon the underlying cause of congenital MG. Since an immune response is not involved in congenital MG, serologic testing for AChR antibody is negative and should not be performed. A biopsy of the external intercostal muscle collected origin to insertion can be used to quantify a reduced number or lack of AChRs at the neuromuscular junction. There may not be a response to the edrophonium chloride test if there is complete absence of receptors.
1074ĭiagnosis is based on signalment and clinical signs of fatigue during ambulation. 1068,1072,1073 Congenital myasthenia syndrome due to a mutation in the gene encoding the epsilon subunit ( bovCHRNE) of the AChR has been documented as an autosomal recessive trait in Red Brahman cattle in South Africa. 1072 Autosomal recessive inheritance has been determined for the Jack Russell and smooth fox terriers and the Gammel Dansk honsehund. Myasthenic syndrome, in which there is a presynaptic defect in the release of ACh, has been described in the Gammel Dansk honsehund dog. 1070,1071 The congenital form is caused by a deficiency of AChR at the postsynaptic membrane, without evidence of autoimmunity. 1069 Congenital MG has been described in few cats. Marc Kent DVM, BA, DACVIM, in Handbook of Veterinary Neurology (Fifth Edition), 2011 Anomalies Congenital Myasthenia GravisĬongenital MG, a rare disease, has been mainly documented in young dogs including English springer spaniels, 1066 dachshunds, 1067 Jack Russell terriers, 1068 and smooth fox terriers.