Diagnosis of transmissible spongiform encephalopathies in Spain. Population perspective

OBJECTIVES: To describe specific aspects of the diagnostic process of transmissible spongiform encephalopathies in Spain and to evaluate the 14-3-3 protein test in cerebrospinal fluid. METHODS: The annual pattern of diagnostic certainty as well as those of demand and results of biochemical and genetic studies were studied using two sets of patients, those diagnosed for the 1993-1998 period, notified to a National Creutzfeldt-Jakob Disease Register (NCDJR), and those referred to the Tissue Bank for Neurological Research Laboratory (TBNRL). The 14-3-3 protein test was validated taking as a reference two clinical populations. RESULTS: Two-hundred and four Creutzfeldt-Jakob disease cases were registered at the NCDJR: 39 out of them and 28 other patients had been studied at the TBNRL. The proportion of definite Creutzfeldt-Jakob Disease cases decreased since 1996. Among those registered in 1997-1998, 35.5%, 36% and 20% had undergone 14-3-3 protein in LCR, histopathologic and genetic studies. The 14-3-3 test grave, for definite, sporadic Creutzfeldt-Jakob disease as compared for patients with other dementing disorders, the following data: 12/13 sensitivity; 33/35 specificity; and 12/14 and 33/34 predictive values of positive and negative test. Two familial cases were diagnosed by identification of mutations in the TBNRL. CONCLUSIONS: The results suggest that: a) the diagnostic certainty of Creutzfeldt-Jakob disease in Spain decreased due to a drop in autopsy rates; b) the 14-3-3 cerebrospinal fluid test has a high diagnostic value, and its use diffused rapid but incompletely; c) genetic studies are useful in some cases, and d) Creutzfeldt-Jakob disease undereporting may be considerable. Creutzfeldt-Jakob disease diagnosis and surveillance, are closely related and being consolidated in Spain.