[Familial amyloid neuropathies].

Recent advances in molecular biology have given improved knowledge of familial amyloidotic polyneuropathies (FAP). FAP, originally described in Portuguese patients have been observed in many countries. These neuropathies are characterized by a sensory motor deficit beginning in the lower limbs and associated with autonomic nervous system involvement and tropic lesions of the feet in a few patients. FAP are associated with alterations or the transthyretin (TTR) gene located on chromosome 18, resulting in variants of the molecule. In a few cases a carpal tunnel syndrome is the presenting feature with a secondary sensory motor neuropathy. Sensory motor neuropathy is associated with renal failure in FAP where the amyloid deposits are composed of a variant of the apolipoprotein A1 molecule. the gene for apolipoprotein A1 is on chromosome 11. In FAP, originally described in Finland, clinical features include lattice corneal dystrophy and cranial neuropathy. The amyloid deposits contain a variant of plasma gelsolin, the gene of which is located on chromosome 9. The course of these FAPs is serious, and patients are bedridden after 10 years. At present, there is no specific therapy; however, liver transplantation could be a possible treatment. Molecular biology identifying genetic mutations allows the detection of gene carriers.