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Peripheral Neuropathiesin ChildrenProf. M. A. M. SalihThe paper provides an update on acute and chronic forms of peripheral neuropathiesin children. Acute forms result in acute flaccial paralysis and include neuropathiesof infectious diseases such as diphtheria, brucellosis and neuroborreliosis. They alsoinclude acute toxic neuropathies due to heavy metals (lead and mercury) and organophosphates.Following success in controlling immunizable diseases in childhood, theimmune-mediated neuropathy, Guillain-Barre syndrome, is gaining significant importance.The review will highlight the subtypes of Guillaine Barre syndrome (includingMiller Fisher syndrome), their pathogenesis and recommended protocols for theirmanagement.Chronic forms, on the other hand, encompass the inherited diseases of the peripheralnerves. Of these, the autosomal recessive (AR) types of Charcot-Marie-Tooth (CMT)are relatively more prevalent in North Africa and the Arabian Peninsula because ofthe high rate of consanguinity. This contrasts with the mainly dominant forms seenin Europe and the US. Two major phenotypes have been distinguished, in which theneuropathy is either demyelinating (CMTl) or axonal (CMT2). Several new entitieswere described in highly inbred Saudi Arabian and North African countries. Currently,more than 9 loci and 6 genes have been identified.In a collaborative research, we described the first identified gene causing an AR type ofCMT. The gene (Myotubularin-related 2 gene, MTMR2) and its mutations that lead toan AR severe demyelinating neuropathy, was identified in one Italian kindred and twoSaudi Arabian families. This gene, located on chromosome 11q22, was found to encodethe myotubularin related protein2. Further studies on the Saudi and Italian familiesrevealed that MTMR2 interacts with neurofilament light chain protein (NF-L), thedeficiency of which causes another axonal form of CMT (CMT2E). The data furthersupported the notion that hereditary demyelinating and axonal neuropathies may representdifferential clinical manifestations of a common pathological mechanism.Other phenotypically novel myelinopathies, axonopathies and other complex forms ofCMT that have been described in North African and Saudi Arabian populations awaitto have their genetic loci unravelled. In another joint study, we described a new genethat causes spinocerebellar ataxia associated with axonal neuropathy (SCAN 1). Thegene, Tyrosyl-DNA phosphodiesterase 1 (TDP 1) may cause SCAN I either by interferingwith DNA transcription or by inducing apoptosis in postmitolic neurons.