Determinación y jerarquización de signos clínicos para diagnóstico temprano de xantomatosis cerebrotendinosa / Determination and hierarchy of clinical signs for early detection of cerebrotendinous xanthomatosis

ABSTRACT

Background: Cerebrotendinous Xanthomatosis (CTX) is an autosomal recessive disease caused by mutations in the CYP27A1 gene resulting in a decreased synthesis of bile acids. An early diagnosis and treatment would reduce the longterm complications observed in this disease. Aim: To identify and hierarchize initial clinical signs of CTX to establish an early diagnostic suspicion index. Material and Methods: Clinical information was collected from 387 patients diagnosed with CTX, published in MEDLINE between 1968 and 2016. Clinical manifestations were identified, determining their prevalence and age of onset. Sensitivity, specificity and the positive Likelihood ratio (LR+) was calculated for each clinical sign evaluated. Results: The average ages for early symptoms' onset and CTX diagnosis were 13.3 ± 10.6 years and 34.6 ± 12.6 years respectively. The early clinical signs and their respective LR+ were juvenile cataracts (143), epilepsy (81), chronic diarrhea (15.6) and psychomotor development delay (3.4). The presence of consanguinity among parents resulted in a LR+ of 31. The combination of two early signs increased the post-test probability to 30%. If the early diagnostic criteria would have been applied in three Chilean patients with diagnosis of CTX, their disease would have been diagnosed from 12 to 25 years earlier. Conclusions: The use of a hierarchical system of predictive clinical signs allows an early screening of CTX, which may avoid the natural progression of the disease using an appropriate treatment.