CHAT and congenital myasthenic syndrome: While bone involvement in MG is well described in adults, particularly in GC users, two variants of MG characterized by bone damage occurring in embryonic and postnatal periods, such as congenital and neonatal myasthenia (NM), have been identified: congenital myasthenia is an autosomal recessive inherited disorder of the childhood, resulting from choline acetyltransferase (ChAT) deficiency and postsynaptic anomalies.