Reliability of a visual test for the rapid detection of mucopolysaccharidoses: GAG-test(®).

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders, characterized by the deficiency/absence of one of the enzymes involved in the intralysosomal degradation of glycosaminoglycans (GAGs). The quantitative determination of urinary GAGs using dimethylmethylene blue (DMB) shows high reliability. However, the logistics and staff for this method are not always available in primary care centers. Sending urine samples to reference laboratories increases the cost and delays the diagnosis. Thus, the aim of this article is to develop and evaluate a simple and low-cost visual test (GAG-test(®)) for the screening of urine samples from patients under suspicion of suffering from MPS. The purpose is to narrow down the number of samples to be assayed through the quantitative method. A measure of 50 µl urine was added to 2 ml DMB solution. A color change from dark blue to purple indicates an excess of GAGs. The quantitative analyses showed a significant difference between controls' and patients' concentrations (P<0.05). After optimization of the composition, positive and negative results obtained with the qualitative test were able to discriminate between normal urines and those from patients suffering from mucopolysaccharidosis. Therefore, GAG-test(®) has proved to be a useful tool for the prior diagnosis of patients suffering from mucopolysaccharidosis, reducing the number of individuals with whom investigations should be continued.

Update on lysosomal acid lipase deficiency: Diagnosis, treatment and patient management. / Actualización en deficiencia de lipasa ácida lisosomal: diagnóstico, tratamiento y seguimiento de los pacientes.

Lysosomal acid lipase deficiency (LALD) is an ultra-rare disease caused by a congenital disorder of the lipid metabolism, characterized by the deposition of cholesterol esters and triglycerides in the organism. In patients with no enzyme function, the disease develops during the perinatal period and is invariably associated with death during the first year of life. In all other cases, the phenotype is heterogeneous, although most patients develop chronic liver diseases and may also develop an early cardiovascular disease. Treatment for LALD has classically included the use of supportive measures that do not prevent the progression of the disease. In 2015, regulatory agencies approved the use of a human recombinant LAL for the treatment of LALD. This long-term enzyme replacement therapy has been associated with significant improvements in the hepatic and lipid profiles of patients with LALD, increasing survival rates in infants with a rapidly progressive disease. Both the severity of LALD and the availability of a specific treatment highlight the need to identify these patients in clinical settings, although its low prevalence and the existing clinical overlap with other more frequent pathologies limit its diagnosis. In this paper we set out practical recommendations to identify and monitor patients with LALD, including a diagnostic algorithm, along with an updated treatment.