Clinical, biochemical and molecular characterization of prosaposin deficiency

Prosaposin (PSAP) deficiency is an ultra-rare, fatal infantile lysosomal storage disorder (LSD) caused by variants in the PSAP gene, with 7 subjects reported so far. Here, we provide the clinical, biochemical and molecular characterization of two additional PSAP deficiency cases. Lysoplex, a targeted resequencing approach was utilized to identify the variant in the first patient, while quantification of plasma lysosphingolipids (lysoSLs), assessed by liquid chromatography mass spectrometry (LC-MS/MS) and brain magnetic resonance imaging (MRI), followed by Sanger sequencing allowed to attain diagnosis in the second case. Functional studies were carried out on patients' fibroblast lines to explore the functional impact of variants. The two patients were homozygous for two different truncating PSAP mutations (c.895G>T, p.Glu299*; c.834_835delGA, p.Glu278Aspfs*27). Both variants led to a complete lack of processed transcript. LC-MS/MS and brain MRI analyses consistently provided a distinctive profile in the two children. Quantification of specific plasma lysoSLs revealed elevated levels of globotriaosylsphingosine (lysoGb3) and glucosylsphingosine (GlSph), and accumulation of autophagosomes, due to a decreased autophagic flux, was observed. This report documents the successfully use of plasma lysoSLs profiling in the PSAP deficiency diagnosis, as a reliable and informative tool to obtain a preliminary information in infantile cases with complex traits displaying severe neurological signs and visceral involvement.Prosaposin (PSAP) deficiency is an ultra-rare, fatal infantile lysosomal storage disorder (LSD) caused by variants in the PSAP gene, with seven subjects reported so far. Here, we provide the clinical, biochemical and molecular characterization of two additional PSAP deficiency cases. Lysoplex, a targeted resequencing approach was utilized to identify the variant in the first patient, while quantification of plasma lysosphingolipids (lysoSLs), assessed by liquid chromatography mass spectrometry (LC-MS/MS) and brain magnetic resonance imaging (MRI), followed by Sanger sequencing allowed to attain diagnosis in the second case. Functional studies were carried out on patients' fibroblast lines to explore the functional impact of variants. The two patients were homozygous for two different truncating PSAP mutations (c.895G>T, p.Glu299*; c.834_835delGA, p.Glu278Aspfs*27). Both variants led to a complete lack of processed transcript. LC-MS/MS and brain MRI analyses consistently provided a distinctive profile in the two children. Quantification of specific plasma lysoSLs revealed elevated levels of globotriaosylsphingosine (LysoGb3) and glucosylsphingosine (GlSph), and accumulation of autophagosomes, due to a decreased autophagic flux, was observed. This report documents the successful use of plasma lysoSLs profiling in the PSAP deficiency diagnosis, as a reliable and informative tool to obtain a preliminary information in infantile cases with complex traits displaying severe neurological signs and visceral involvement

Quality of Life (QoL) assessment in a cohort of patients with Phenylketonuria

Background: Phenylketonuria (PKU) is a chronic inborn error of amino acid metabolism that requires lifelong follow-up and intervention, which may represent strains on Quality of Life (QoL). This observational study evaluated QoL in a cohort of PKU patients, using updated and detailed instruments. Methods: 22 patients with mild PKU respondent to BH4 and 21 patients with classical PKU treated with diet were recruited in this study. Adult patients completed WHOQOL questionnaire-100 (WHOQOL-100) and pediatric patients the Pediatric QoL inventory (PedsQL™). Psychiatric and mood disorders were also evaluated using TAD or BDI and STAI-Y inventories. A multivariable linear regression model was fitted to investigate the predictors of QoL, including age, sex, treatment type, length of current treatment, educational level and employment status (only for adults) as covariates. Results were presented as regression coefficients with 95% confidence interval. Results: Global QoL scores were within normal range both in patients with mild and classical disease but global QoL scores were significantly higher in patients with mild PKU under BH4 treatment as compared to those affected by classical disease who were under diet regimen. Furthermore, QoL significantly increased in long treated PKU patients. Among adult patients, QoL scores were significantly lower in males, in patients with lower education and in those employed or unemployed as compared to students (baseline). Conclusions: Both diet and medical treatment based upon BH4 seem to be associated with higher QoL in the long run. However, patients with mild PKU can rely on BH4 to achieve a higher Phe tolerance and a better compliance to therapy due to diet relaxation/avoidance. Some specific categories of patients with a lower QoL should be investigated more in depth, engaging with those at risk of lower treatment compliance. The questionnaires employed in the present study seemed to be able to effectively detect criticalities in QoL assessment and represent an advance from previous inventories employed in the past

Quality of Life (QoL) assessment in a cohort of patients with Phenylketonuria

Background: Phenylketonuria (PKU) is a chronic inborn error of amino acid metabolism that requires lifelong follow-up and intervention, which may represent strains on Quality of Life (QoL). This observational study evaluated QoL in a cohort of PKU patients, using updated and detailed instruments. Methods: 22 patients with mild PKU respondent to BH<inf>4</inf> and 21 patients with classical PKU treated with diet were recruited in this study. Adult patients completed WHOQOL questionnaire-100 (WHOQOL-100) and pediatric patients the Pediatric QoL inventory (PedsQL^™). Psychiatric and mood disorders were also evaluated using TAD or BDI and STAI-Y inventories. A multivariable linear regression model was fitted to investigate the predictors of QoL, including age, sex, treatment type, length of current treatment, educational level and employment status (only for adults) as covariates. Results were presented as regression coefficients with 95% confidence interval. Results: Global QoL scores were within normal range both in patients with mild and classical disease but global QoL scores were significantly higher in patients with mild PKU under BH<inf>4</inf> treatment as compared to those affected by classical disease who were under diet regimen. Furthermore, QoL significantly increased in long treated PKU patients. Among adult patients, QoL scores were significantly lower in males, in patients with lower education and in those employed or unemployed as compared to students (baseline). Conclusions: Both diet and medical treatment based upon BH<inf>4</inf> seem to be associated with higher QoL in the long run. However, patients with mild PKU can rely on BH<inf>4</inf> to achieve a higher Phe tolerance and a better compliance to therapy due to diet relaxation/avoidance. Some specific categories of patients with a lower QoL should be investigated more in depth, engaging with those at risk of lower treatment compliance. The questionnaires employed in the present study seemed to be able to effectively detect criticalities in QoL assessment and represent an advance from previous inventories employed in the past.A series of secondary diaryl and dialkyl nitrosamines have been synthesised and tested as substrates and/or inhibitors of highly purified acetyl-cholinesterase from Torpedo fuscomaculata. None were found to act as substrate, but many could selectively inhibit the enzyme. Kinetic analysis has shown that all the nitrosamines act as reversible competitive inhibitors with respect to the substrate, acetylthiocholine chloride; with time they act as irreversible covalent inhibitors. Scatchard analysis indicates that aliphatic nitrosamines have a weaker affinity for the enzyme compared to the aromatic and heterocyclic nitrosamines. In all cases the number of binding sites was four. Pseudo first-order kinetics are observed with the rate constant being proportional to the concentration of the nitrosamine and the order of reaction being equal to one. © 1994 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

Current insights into familial spastic paraparesis: new advances in an old disease

Hereditary spastic paraparesis (HSP) comprises a clinically and genetically heterogeneous group of disorders characterized by progressive spasticity and hyperreflexia of the lower limbs. The past few years have witnessed an exponential increase in knowledge of this disease and we can now list 19 loci mapped on the human genome and eight genes cloned. However, this wider knowledge of the molecular basis of HSP has had limited impact on clinical practice: the use of antispastic drugs and regular physiotherapy still remain crucial in the therapeutic management of patients. Nonetheless, the identification of new genes mutated in HSP furthers comprehension of the pathomechanisms involved and helps in genetic counseling, especially of asymptomatic individuals who request molecular analyses